U.S. patent application number 14/420300 was filed with the patent office on 2015-07-23 for coated tool.
This patent application is currently assigned to TUNGALOY CORPORATION. The applicant listed for this patent is Shota Asari, Masakazu Kikuchi. Invention is credited to Shota Asari, Masakazu Kikuchi.
Application Number | 20150203956 14/420300 |
Document ID | / |
Family ID | 50068270 |
Filed Date | 2015-07-23 |
United States Patent
Application |
20150203956 |
Kind Code |
A1 |
Asari; Shota ; et
al. |
July 23, 2015 |
Coated Tool
Abstract
A coated tool includes a substrate and a coating layer disposed
on a surface of the substrate. The coating layer includes a first
stack structure (3) and a second stack structure (4). The first
stack structure has two or more kinds of layers with different
compositions periodically stacked with an average layer thickness
of 60-500 nm. The second stack structure has two or more kinds of
layers with different compositions periodically stacked with an
average layer thickness of 2 nm to less than 60 nm. The layers in
each stack structure include at least one selected from the group
consisting of metal elements Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al,
Si, Sr, Y, Sn and Bi; and compounds including at least one of these
metal elements and at least one non-metal element selected from
carbon, nitrogen, oxygen and boron.
Inventors: |
Asari; Shota; (Iwaki-shi,
JP) ; Kikuchi; Masakazu; (Iwaki-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Asari; Shota
Kikuchi; Masakazu |
Iwaki-shi
Iwaki-shi |
|
JP
JP |
|
|
Assignee: |
TUNGALOY CORPORATION
Iwaki-shi, Fukushima
JP
|
Family ID: |
50068270 |
Appl. No.: |
14/420300 |
Filed: |
August 12, 2013 |
PCT Filed: |
August 12, 2013 |
PCT NO: |
PCT/JP2013/071753 |
371 Date: |
February 6, 2015 |
Current U.S.
Class: |
428/216 |
Current CPC
Class: |
C23C 14/0641 20130101;
Y10T 428/24975 20150115; C23C 28/042 20130101; C23C 30/005
20130101; C23C 28/044 20130101; C23C 28/42 20130101; C23C 14/32
20130101; C23C 14/325 20130101 |
International
Class: |
C23C 14/06 20060101
C23C014/06; C23C 14/32 20060101 C23C014/32 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 10, 2012 |
JP |
2012-177843 |
Aug 24, 2012 |
JP |
2012-185370 |
Claims
1. A coated tool comprising a substrate and a coating layer
disposed on a surface of the substrate, the coating layer including
a first stack structure and a second stack structure, the first
stack structure having a structure in which two or more kinds of
layers with different compositions are periodically stacked wherein
the average layer thickness of each of the layers is 60 nm to 500
nm, the second stack structure having a structure in which two or
more kinds of layers with different compositions are periodically
stacked wherein the average layer thickness of each of the layers
is 2 nm to less than 60 nm, the layers constituting the first stack
structure and the layers constituting the second stack structure
including at least one selected from the group consisting of a
metal including at least one metal element selected from Ti, Zr,
Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, Sr, Y, Sn and Bi; and compounds
including at least one of these metal elements and at least one
non-metal element selected from carbon, nitrogen, oxygen and
boron.
2. The coated tool according to claim 1, wherein the first stack
structure is an alternate stack structure including two kinds of
layers with different compositions stacked alternately each in two
or more layers.
3. The coated tool according to claim 1, wherein the second stack
structure is an alternate stack structure including two kinds of
layers with different compositions stacked alternately each in two
or more layers.
4. The coated tool according to claim 1, wherein the coating layer
includes a structure including the first stack structures and the
second stack structures stacked alternately and continuously each
in two or more structures.
5. The coated tool according to claim 1 any one of claims 1 to 4,
wherein (T.sub.1-T.sub.2) is 20 nm to 996 nm wherein T.sub.1 is the
average value of the stacking periods in the first stack structure
and T.sub.2 is the average value of the stacking periods in the
second stack structure.
6. The coated tool according to claim 1, wherein the layers
constituting the first stack structure and the layers constituting
the second stack structure each include at least one selected from
the group consisting of metals including at least two metal
elements selected from Ti, Nb, Ta, Cr, W, Al, Si, Sr and Y; and
compounds including at least two of these metal elements and at
least one non-metal element selected from carbon, nitrogen, oxygen
and boron.
7. The coated tool according to claim 1, wherein the metal elements
present in the layers constituting the first stack structure are
identical among the layers constituting the first stack structure
and include one or more metal elements having a difference in
absolute value of 5 at % or more between the ratio thereof relative
to the total of the metal elements present in one layer
constituting the first stack structure and the ratio of the
identical metal element relative to the total of the metal elements
present in a layer constituting the first stack structure which
layer is adjacent to the one layer.
8. The coated tool according to claim 1, wherein the metal elements
present in the layers constituting the second stack structure are
identical among the layers constituting the second stack structure
and include one or more metal elements having a difference in
absolute value of 5 at % or more between the ratio thereof relative
to the total of the metal elements present in one layer
constituting the second stack structure and the ratio of the
identical metal element relative to the total of the metal elements
present in a layer constituting the second stack structure which
layer is adjacent to the one layer.
9. The coated tool according to claim 1, wherein one layer
constituting the first stack structure contains one or more metal
elements different from the metal element or elements present in a
layer constituting the first stack structure which layer is
adjacent to the one layer.
10. The coated tool according to claim 1, wherein one layer
constituting the second stack structure contains one or more metal
elements different from the metal element or elements present in a
layer constituting the second stack structure which layer is
adjacent to the one layer.
11. The coated tool according to claim 1, wherein the average total
layer thickness of the entirety of the coating layer is 0.22 to 12
.mu.m.
12. The coated tool according to claim 1, wherein the average
thickness of the first stack structure is 0.2 to 6 .mu.m.
13. The coated tool according to claim 1, wherein the average
thickness of the second stack structure is 0.02 to 6 .mu.m.
14. The coated tool according to claim 2, wherein the coating layer
includes a structure including the first stack structures and the
second stack structures stacked alternately and continuously each
in two or more structures.
15. The coated tool according to claim 3, wherein the coating layer
includes a structure including the first stack structures and the
second stack structures stacked alternately and continuously each
in two or more structures.
16. The coated tool according to claim 4, wherein the layers
constituting the first stack structure and the layers constituting
the second stack structure each include at least one selected from
the group consisting of metals including at least two metal
elements selected from Ti, Nb, Ta, Cr, W, Al, Si, Sr and Y; and
compounds including at least two of these metal elements and at
least one non-metal element selected from carbon, nitrogen, oxygen
and boron.
17. The coated tool according to claim 4, wherein the metal
elements present in the layers constituting the first stack
structure are identical among the layers constituting the first
stack structure and include one or more metal elements having a
difference in absolute value of 5 at % or more between the ratio
thereof relative to the total of the metal elements present in one
layer constituting the first stack structure and the ratio of the
identical metal element relative to the total of the metal elements
present in a layer constituting the first stack structure which
layer is adjacent to the one layer.
18. The coated tool according to claim 16, wherein the metal
elements present in the layers constituting the first stack
structure are identical among the layers constituting the first
stack structure and include one or more metal elements having a
difference in absolute value of 5 at % or more between the ratio
thereof relative to the total of the metal elements present in one
layer constituting the first stack structure and the ratio of the
identical metal element relative to the total of the metal elements
present in a layer constituting the first stack structure which
layer is adjacent to the one layer.
19. The coated tool according to claim 4, wherein the metal
elements present in the layers constituting the second stack
structure are identical among the layers constituting the second
stack structure and include one or more metal elements having a
difference in absolute value of 5 at % or more between the ratio
thereof relative to the total of the metal elements present in one
layer constituting the second stack structure and the ratio of the
identical metal element relative to the total of the metal elements
present in a layer constituting the second stack structure which
layer is adjacent to the one layer.
20. The coated tool according to claim 16, wherein the metal
elements present in the layers constituting the second stack
structure are identical among the layers constituting the second
stack structure and include one or more metal elements having a
difference in absolute value of 5 at % or more between the ratio
thereof relative to the total of the metal elements present in one
layer constituting the second stack structure and the ratio of the
identical metal element relative to the total of the metal elements
present in a layer constituting the second stack structure which
layer is adjacent to the one layer.
Description
TECHNICAL FIELD
[0001] The present invention relates to coated tools.
BACKGROUND ART
[0002] With a recent increase in the demands for enhanced
efficiencies in cutting, there has been a need for a longer life of
cutting tools than heretofore available. Consequently, the
requirement on the properties of tool materials which has become
ever more important is that wear resistance and fracture resistance
associated with the life of cutting tools be enhanced. In order to
obtain enhancements in these properties, coated tools are used in
which an alternate film stack of coating films is disposed on a
substrate.
[0003] Various techniques have been proposed to improve properties
of such alternate film stacks. For example, Patent Literature 1
proposes a highly wear resistant cutting tool in which a specific
metal element or a compound thereof and a specific alloy compound
are stacked with a stacking period of 0.4 nm to 50 nm on the
surface of a base material.
[0004] Patent Literature 2 proposes a cutting tool exhibiting
excellent wear resistance even under heavy cutting conditions. This
tool is such that the surface of a base is coated with 4 or more
layers having an average total layer thickness of 2 to 10 pm which
are in the form of an alternate stack of first thin layers of a
composite nitride represented by the composition formula
(Ti.sub.1-xAl.sub.x)N (x in atomic ratio: 0.30 to 0.70) and second
thin layers containing an aluminum oxide phase in a ratio of 35 to
65 mass % relative to the total of the mass thereof and the mass of
a titanium nitride phase, the average layer thickness of the
individual layers being 0.2 to 1 .mu.m.
[0005] Patent Literature 3 proposes a cutting tool with excellent
wear resistance and welding resistance which is such that 100-5000
nm stack layers including a periodic stack of layers with
thicknesses of 1 to 50 nm, and 100-5000 nm single layers are
alternately stacked in 10 or more layers on top of one another on a
hard base material.
PRIOR ART REFERENCES
Patent Literatures
[0006] Patent Literature 1: Japanese Patent Application Kokai
Publication No. H07-205361 [0007] Patent Literature 2: Japanese
Patent Application Kokai Publication No. 2003-200306 [0008] Patent
Literature 3: Japanese Patent Application Kokai Publication No.
H11-12718
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0009] In recent cutting, tools are subjected to more marked
increases in speed, feed and cut-in depth. Consequently, it is more
frequently the case that cracks that have occurred on the surface
of tools due to the load applied to the cutting edges during the
cutting reach the substrates, or cracks that have occurred in the
substrates due to sharp changes in the temperature of the cutting
edges penetrate into the coating layers, resulting in the fracture
of the tools.
[0010] Although the cutting tool of the invention of Patent
Literature 1 which includes a stack of thin layers with a stacking
period of 0.4 to 50 nm exhibits high wear resistance, the tool is
problematically prone to be fractured under the circumstances
described above. The cutting tool of the invention of Patent
Literature 2 which includes an alternate stack of layers with a
large individual average layer thickness has a problem in that the
hardness of the coating films is so insufficient that the tool
exhibits poor wear resistance. In the cutting tool of the invention
of Patent Literature 3 which has a stacked structure formed of
stack layers of thin films and single layers, the fracture
resistance is insufficient and the tool cannot more often satisfy
the required performance described hereinabove.
[0011] The present invention has been made to solve these problems.
It is therefore an object of the invention to provide long-life
coated tools which are enhanced in fracture resistance without any
decrease in wear resistance.
Means to Solve the Problems
[0012] The present inventors carried out studies on the extension
of the life of coated tools. The present inventors have then found
that fracture resistance may be enhanced without causing a decrease
in wear resistance by improving the layer configurations and the
compositions of coating layers. As a result, the extension of the
life of coated tools has been realized.
[0013] Specifically, the present invention may be summarized as
follows.
[0014] (1) A coated tool comprising a substrate and a coating layer
disposed on a surface of the substrate, the coating layer including
a first stack structure and a second stack structure, the first
stack structure having a structure in which two or more kinds of
layers with different compositions are periodically stacked wherein
the average layer thickness of each of the layers is 60 nm to 500
nm, the second stack structure having a structure in which two or
more kinds of layers with different compositions are periodically
stacked wherein the average layer thickness of each of the layers
is 2 nm to less than 60 nm, the layers constituting the first stack
structure and the layers constituting the second stack structure
including at least one selected from the group consisting of a
metal including at least one metal element selected from Ti, Zr,
Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, Sr, Y, Sn and Bi; and compounds
including at least one of these metal elements and at least one
non-metal element selected from carbon, nitrogen, oxygen and
boron.
[0015] (2) The coated tool of (1), wherein the first stack
structure is an alternate stack structure including two kinds of
layers with different compositions stacked alternately each in two
or more layers.
[0016] (3) The coated tool of (1) or (2), wherein the second stack
structure is an alternate stack structure including two kinds of
layers with different compositions stacked alternately each in two
or more layers.
[0017] (4) The coated tool of any of (1) to (3), wherein the
coating layer includes a structure including the first stack
structures and the second stack structures stacked alternately and
continuously each in two or more layers.
[0018] (5) The coated tool of any of (1) to (4), wherein
(T.sub.1-T.sub.2) is 20 nm to 996 nm wherein T.sub.1 is the average
value of the stacking periods in the first stack structure and
T.sub.2 is the average value of the stacking periods in the second
stack structure.
[0019] (6) The coated tool of any of (1) to (5), wherein the layers
constituting the first stack structure and the layers constituting
the second stack structure each include at least one selected from
the group consisting of metals including at least two metal
elements selected from Ti, Nb, Ta, Cr, W, Al, Si, Sr and Y; and
compounds including at least two of these metal elements and at
least one non-metal element selected from carbon, nitrogen, oxygen
and boron.
[0020] (7) The coated tool of any of (1) to (6), wherein the metal
elements present in the layers constituting the first stack
structure are identical among the layers constituting the first
stack structure and include one or more metal elements having a
difference in absolute value of 5 at % or more between the ratio
thereof relative to the total of the metal elements present in one
layer constituting the first stack structure and the ratio of the
identical metal element relative to the total of the metal elements
present in a layer constituting the first stack structure which
layer is adjacent to the one layer.
[0021] (8) The coated tool of any of (1) to (7), wherein the metal
elements present in the layers constituting the second stack
structure are identical among the layers constituting the second
stack structure and include one or more metal elements having a
difference in absolute value of 5 at % or more between the ratio
thereof relative to the total of the metal elements present in one
layer constituting the second stack structure and the ratio of the
identical metal element relative to the total of the metal elements
present in a layer constituting the second stack structure which
layer is adjacent to the one layer.
[0022] (9) The coated tool of any of (1) to (6), wherein one layer
constituting the first stack structure contains one or more metal
elements different from the metal element or elements present in a
layer constituting the first stack structure which layer is
adjacent to the one layer.
[0023] (10) The coated tool of any of (1) to (6) and (9), wherein
one layer constituting the second stack structure contains one or
more metal elements different from the metal element or elements
present in a layer constituting the second stack structure which
layer is adjacent to the one layer.
[0024] (11) The coated tool of any of (1) to (10), wherein the
average total layer thickness of the entirety of the coating layer
is 0.22 to 12 .mu.m.
[0025] (12) The coated tool of any of (1) to (11), wherein the
average thickness of the first stack structure is 0.2 to 6
.mu.m.
[0026] (13) The coated tool of any of (1) to (12), wherein the
average thickness of the second stack structure is 0.02 to 6
.mu.m.
Effects of the Invention
[0027] The coated tools of the present invention have excellent
wear resistance and fracture resistance to achieve a longer tool
life than heretofore possible.
BRIEF DESCRIPTION OF DRAWING
[0028] FIG. 1 is an example of schematic views illustrating a
sectional structure of a coated tool of the present invention.
DESCRIOTION OF EMBODIMENTS
[0029] A coated tool of the present invention includes a substrate
and a coating layer disposed on a surface of the substrate. The
substrates in the present invention are not particularly limited,
and any substrates of coated tools may be used. Examples thereof
include cemented carbides, cermets, ceramics, sintered cubic boron
nitrides, sintered diamonds and high-speed steels. In particular,
cemented carbide substrates are more preferable due to excellent
wear resistance and fracture resistance.
[0030] Wear resistance tends to be decreased if the average total
layer thickness of the entirety of the coating layer in the coated
tool of the present invention is less than 0.22 .mu.m. A decrease
in fracture resistance tends to be caused if the average total
layer thickness of the entirety of the coating layer exceeds 12
.mu.m. It is therefore preferable that the average total layer
thickness of the entirety of the coating layer be 0.22 to 12 .mu.m.
In particular, the average total layer thickness of the entirety of
the coating layer is more preferably 1.0 to 8.0 .mu.m.
[0031] As described hereinabove, the coating layer in the coated
tool of the present invention includes a specific first stack
structure and a specific second stack structure. Each of the layers
constituting the first stack structure includes at least one
selected from the group consisting of:
[0032] a metal including at least one metal element selected from
Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, Sr, Y, Sn and Bi; and
[0033] compounds including at least one of these metal elements and
at least one non-metal element selected from carbon, nitrogen,
oxygen and boron. Such layers exhibit excellent wear
resistance.
[0034] In particular, it is more preferable that the layers
constituting the first stack structure include at least one
selected from the group consisting of:
[0035] metals including at least two metal elements selected from
Ti, Nb, Ta, Cr, W, Al, Si, Sr and Y; and
[0036] compounds including at least two of these metal elements and
at least one non-metal element selected from carbon, nitrogen,
oxygen and boron. This configuration adds hardness. Specific
examples of the metals or the compounds for forming the constituent
layers in the first stack structure include
(Al.sub.0.50Ti.sub.0.50)N, (Al.sub.0.60Ti.sub.0.40)N,
(Al.sub.0.67Ti.sub.0.33)N, (Al.sub.0.67Ti.sub.0.33)CN,
(Al.sub.0.45Ti.sub.0.45Si.sub.0.10)N,
(Al.sub.0.45Ti.sub.0.45Y.sub.0.10)N,
(Al.sub.0.50Ti.sub.0.30Cr.sub.0.20)N,
(Al.sub.0.50Ti.sub.0.45Nb.sub.0.05)N,
(Al.sub.0.50Ti.sub.0.45Ta.sub.0.05)N,
(Al.sub.0.50Ti.sub.0.45W.sub.0.05)N, (Ti.sub.0.90Si.sub.0.10)N and
Al.sub.0.50Cr.sub.0.50)N.
[0037] In the coating layer in the coated tool of the present
invention, the first stack structure has a structure in which two
or more kinds of layers including any of these metals or compounds
are periodically stacked on top of one another with each layer
having an average layer thickness of 60 nm to 500 nm. This stack
structure having a specific periodicity includes two or more kinds
of layers with different compositions. To prevent the penetration
of cracks and to obtain enhanced fracture resistance, it is
preferable that these layers with different compositions be stacked
alternately each in two or more layers.
[0038] In the invention, the thickness of the minimum unit whose
repetition makes up the stack is written as the "stacking period".
The stacking period will be explained below with reference to FIG.
1 which is an example of schematic views illustrating a sectional
structure of a coated tool of the invention. When, for example, the
stack consists of the repetition of Layer A1 (5), Layer B1 (6),
Layer C1 and Layer D1 having different compositions in the order of
Layer A1 Layer B1.fwdarw.Layer C1.fwdarw.Layer D1.fwdarw.Layer
A1.fwdarw.Layer B1.fwdarw.Layer C1.fwdarw.Layer D1.fwdarw. . . .
from the substrate 1 toward the surface of the coating layer 2, the
total of the layer thicknesses of Layer A1 to Layer D1 is defined
as the "stacking period". In the case where the stack consists of
the repetition of Layer A1 (5) and Layer B1 (6) having different
compositions in the order of Layer A1.fwdarw.Layer B1.fwdarw.Layer
A1.fwdarw.Layer B1.fwdarw.Layer A1.fwdarw.Layer B1.fwdarw. . . .
from the substrate 1 toward the surface of the coating layer 2, the
"stacking period" indicates the total of the layer thickness of
Layer A1 and the layer thickness of Layer B1.
[0039] With the configuration in which the layers having different
compositions and respective average layer thicknesses of 60 nm to
500 nm are stacked with the above periodicity, a crack that has
occurred in the surface of the coating layer during the use of the
coated tool is prevented from penetrating to the substrate.
Specifically, such a crack that has reached the first stack
structure is caused to advance in a direction parallel to the
interface between the layers with different compositions.
Advantageously, this effect is further enhanced when an alternate
stack structure is adopted in which two kinds of layers having
different compositions are stacked alternately each in two or more
layers. Specifically, the first stack structure is preferably an
alternate stack structure in which Layers A1 and Layers B1 with
different compositions are stacked alternately each in two or more
layers in the order of Layer A1.fwdarw.Layer B1.fwdarw.Layer
A1.fwdarw.Layer B1.fwdarw. . . . from the substrate toward the
surface of the coating layer.
[0040] Regarding each of the layers constituting the first stack
structure in the coating layer in the coated tool of the present
invention, any average layer thickness of each layer that is less
than 60 nm results in a decrease in the effect of preventing the
penetration of cracks to the substrate. On the other hand, fracture
resistance is reduced if the average layer thickness exceeds 500
nm. Thus, the average layer thickness of each of the layers
constituting the first stack structure is limited to 60 nm to 500
nm. More preferably, the average layer thickness of each of the
layers constituting the first stack structure is 60 nm to 250
nm.
[0041] If the average thickness of the first stack structure is
less than 0.2 .mu.m, the first stack structure has so small a
number of repetitions of the periodic stacking of the layers with
different compositions that the first stack structure tends to
decrease the effect of suppressing the penetration of cracks to the
substrate. On the other hand, any average thickness exceeding 6
.mu.m results in an increase in the residual compressive stress in
the entirety of the coating layer, and consequently the coating
layer is prone to be separated or fractured, namely, tends to
exhibit poor fracture resistance. Thus, the average thickness of
the first stack structure in the present invention is more
preferably 0.2 to 6 .mu.m.
[0042] As described hereinabove, the coating layer in the coated
tool of the invention includes a second stack structure. The layers
constituting the second stack structure include at least one
selected from the group consisting of:
[0043] a metal including at least one metal element selected from
Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, Sr, Y, Sn and Bi; and
[0044] compounds including at least one of these metal elements and
at least one non-metal element selected from carbon, nitrogen,
oxygen and boron. Such layers exhibit excellent wear
resistance.
[0045] In particular, it is more preferable that the layers
constituting the second stack structure include at least one
selected from the group consisting of:
[0046] metals including at least two metal elements selected from
Ti, Nb, Ta, Cr, W, Al, Si, Sr and Y; and
[0047] compounds including at least two of these metal elements and
at least one non-metal element selected from carbon, nitrogen,
oxygen and boron. This configuration adds hardness. Specific
examples of the metals or the compounds for forming the constituent
layers in the second stack structure include
(Al.sub.0.50Ti.sub.0.50)N, (Al.sub.0.60Ti.sub.0.40)N,
(Al.sub.0.67Ti.sub.0.33)N, (Al.sub.0.67Ti.sub.0.33)CN,
(Al.sub.0.45Ti.sub.0.45Si.sub.0.10)N,
(Al.sub.0.45Ti.sub.0.45Y.sub.0.10)N,
(Al.sub.0.50Ti.sub.0.30Cr.sub.0.20)N,
(Al.sub.0.50Ti.sub.0.45Nb.sub.0.05)N,
(Al.sub.0.50Ti.sub.0.45Ta.sub.0.05)N,
(Al.sub.0.50Ti.sub.0.45W.sub.0.05)N, (Ti.sub.0.90Si.sub.0.10)N and
(Al.sub.0.50Cr.sub.0.50)N.
[0048] The second stack structure in the present invention has a
structure in which two or more kinds of layers including any of
these metals or compounds are periodically stacked on top of one
another with each layer having an average layer thickness of 2 nm
to less than 60 nm. This stack structure having a specific
periodicity includes two or more kinds of layers with different
compositions. To ensure high hardness and to obtain enhanced wear
resistance, it is preferable that the second stack structure be an
alternate stack structure in which these layers with different
compositions are stacked alternately each in two or more
layers.
[0049] In the second stack structure, similarly as described above,
the thickness of the minimum unit whose repetition makes up the
stack is written as the "stacking period". Referring to FIG. 1 as
an example, when the stack consists of the repetition of Layer A2
(7), Layer B2 (8), Layer C2 and Layer D2 having different
compositions in the order of Layer A2.fwdarw.Layer B2.fwdarw.Layer
C2.fwdarw.Layer D2.fwdarw.Layer A2.fwdarw.Layer B2.fwdarw.Layer
C2.fwdarw.Layer D2.fwdarw. . . . from the substrate 1 toward the
surface of the coating layer 2, the total of the layer thicknesses
of Layer A2 to Layer D2 is defined as the "stacking period". In the
case where the stack consists of the repetition of Layer A2 (7) and
Layer B2 (8) having different compositions in the order of Layer
A2.fwdarw.Layer B2.fwdarw.Layer A2.fwdarw.Layer B2.fwdarw.Layer
A2.fwdarw.Layer B2.fwdarw. . . . from the substrate 1 toward the
surface of the coating layer 2, the "stacking period" indicates the
total of the layer thickness of Layer A2 and the layer thickness of
Layer B2.
[0050] With the configuration in which the layers having different
compositions and respective average layer thicknesses of 2 nm to
less than 60 nm are stacked with the above periodicity, the second
stack structure in the coated tool of the present invention attains
high hardness to achieve an enhancement in wear resistance.
Advantageously, this effect is further enhanced when an alternate
stack structure is adopted in which two kinds of layers having
different compositions are stacked alternately each in two or more
layers. Specifically, the second stack structure is more preferably
an alternate stack structure in which Layers A2 and Layers B2 with
different compositions are stacked alternately each in two or more
layers in the order of Layer A2.fwdarw.Layer B2.fwdarw.Layer
A2.fwdarw.Layer B2.fwdarw. . . . from the substrate toward the
surface of the coating layer.
[0051] If the average layer thickness of each of the layers
constituting the second stack structure is less than 2 nm, a
difficulty is encountered in forming the layer with a uniform
thickness. If the average layer thickness of each of the layers
constituting the second stack structure is 60 nm or more, hardness
is reduced to cause a decrease in wear resistance. Further, such a
second stack structure has little difference in layer thickness
from the first stack structure with the result that it is hard to
fully achieve the effect of suppressing the penetration of cracks
to the substrate by causing a crack to advance in a direction
parallel to the interface between the first stack structure and the
second stack structure. Thus, the average layer thickness of each
of the layers constituting the second stack structure in the
present invention is limited to 2 nm to less than 60 nm. From the
above viewpoints, the average layer thickness of each of the layers
constituting the second stack structure is more preferably 5 nm to
30 nm.
[0052] If the average thickness of the second stack structure is
less than 0.02 .mu.m, the second stack structure has so small a
number of repetitions of the periodic stacking of the layers that
the enhancement in hardness cannot be obtained. On the other hand,
any average thickness of the second stack structure exceeding 6
.mu.m results in an increase in the residual compressive stress in
the second stack structure, and consequently the coating layer is
prone to be separated or fractured, namely, tends to exhibit poor
fracture resistance. Thus, the average thickness of the second
stack structure is preferably 0.02 to 6 .mu.m.
[0053] The coated tool of the present invention preferably has a
difference between T.sub.1 and T.sub.2 (T.sub.1-T.sub.2) of 20 to
996 nm wherein T.sub.1 is the average value of the stacking periods
in the first stack structure and T.sub.2 is the average value of
the stacking periods in the second stack structure. If the
difference (T.sub.1-T.sub.2) is less than 20 nm, the coated tool
tends to decrease its effect of suppressing the penetration of
cracks to the substrate by causing a crack to advance in a
direction parallel to the interface between the first stack
structure and the second stack structure. If, on the other hand,
the difference between T.sub.1 and T.sub.2 (T.sub.1-T.sub.2)
exceeds 996 nm, the average thickness of the first stack structure
is so large that fracture resistance tends to be decreased. In
particular, the difference between T.sub.1 and T.sub.2
(T.sub.1-T.sub.2) is more preferably 20 to 500 nm, and still more
preferably 20 to 250 nm.
[0054] Provided that the unit "Layer A2.fwdarw.Layer B2" is
repeatedly stacked on top of one another 100 times, the average
value of the stacking periods is calculated by obtaining the total
of the stacking periods of the 100 repeating units "Layer
A2.fwdarw.Layer B2.fwdarw.Layer A2.fwdarw.Layer B2.fwdarw.Layer
A2.fwdarw.Layer B2.fwdarw. . . . " and dividing the total of the
stacking periods by the number of repetitions, namely, 100.
[0055] In a preferred embodiment of the coated tool of the present
invention, the metal elements present in the layers constituting
the first stack structure are identical among the layers
constituting the first stack structure and include one or more
metal elements having a difference in absolute value of 5 at % or
more between the ratio thereof relative to the total of the metal
elements present in one layer constituting the first stack
structure and the ratio of the identical metal element relative to
the total of the metal elements present in another layer
constituting the first stack structure which is adjacent to the one
layer.
[0056] With this configuration, misalignment of crystal lattices
may be obtained at the interface between adjacent layers
constituting the first stack structure without causing any decrease
in adhesion between the layers. Consequently, the structure may
easily cause a crack to advance in a direction parallel to the
interface between the layers constituting the first stack
structure, and is therefore more advantageous in that the effect of
suppressing the penetration of cracks to the substrate is
enhanced.
[0057] The phrase that the metal elements "include one or more
metal elements which have a difference in absolute value of 5 at %
or more" will be described. When, for example, the first stack
structure includes (Al.sub.0.55Ti.sub.0.45)N layers and
(Al.sub.0.67Ti.sub.0.33)N layers, the two kinds of layers include
identical metal elements, namely, Al element and Ti element. The
ratio of the Al element present in the (Al.sub.0.55Ti.sub.0.45)N
layer is 55 at % relative to the total of the metal elements, and
the ratio of the Al element present in the
(Al.sub.0.67Ti.sub.0.33)N layer is 67 at % relative to the total of
the metal elements. Thus, the difference in the ratio of the Al
element between the two layers is 12 at %, satisfying the above
requirement. Further, (Al.sub.0.49Ti.sub.0.39Cr.sub.0.12)N layers
and (Al.sub.0.56Ti.sub.0.36Cr.sub.0.08)N layers will be discussed.
These two kinds of layers include identical metal elements, namely,
Al element, Ti element and Cr element. Although the difference in
the ratio of the Ti element between the two layers is 3 at % and
the difference in the ratio of the Cr element between the two
layers is 4 at %, namely, the differences for both elements are
less than 5 at %, the structure satisfies the requirement because
the difference in the Al ratio between the two layers is 7 at
%.
[0058] In the present invention, nitrides are sometimes written as
(M.sub.aL.sub.b)N with the letter a indicating the atomic ratio of
the element M and the letter b indicating the atomic ratio of the
element L relative to the total of the metal elements. For example,
(Al.sub.0.55Ti.sub.0.45)N means that the atomic ratio of the Al
element relative to the total of the metal elements is 0.55 and the
atomic ratio of the Ti element relative to the total of the metal
elements is 0.45, namely, the ratio of the Al element relative to
the total of the metal elements is 55 at % and the ratio of the Ti
element relative to the total of the metal elements is 45 at %.
[0059] In a preferred embodiment of the coated tool of the present
invention, the metal elements present in the layers constituting
the second stack structure are identical among the layers
constituting the second stack structure and include one or more
metal elements having a difference in absolute value of 5 at % or
more between the ratio thereof relative to the total of the metal
elements present in one layer constituting the second stack
structure and the ratio of the identical metal element relative to
the total of the metal elements present in another layer
constituting the second stack structure which is adjacent to the
one layer.
[0060] With this configuration, misalignment of crystal lattices
may be obtained at the interface between adjacent layers
constituting the second stack structure without causing any
decrease in adhesion between the layers. Consequently, the
structure may easily cause a crack to advance in a direction
parallel to the interface between the layers constituting the
second stack structure, and is therefore more advantageous in that
the effect of suppressing the penetration of cracks to the
substrate is enhanced. The meaning of the phrase that the metal
elements "include one or more metal elements which have a
difference in absolute value of 5 at % or more" is the same as
described above with respect to the first stack structure.
[0061] In another embodiment of the coated tool of the present
invention, it is more preferable that one layer constituting the
first stack structure and another layer constituting the first
stack structure which is adjacent to the one layer include one or
more metal elements different between the layers. With such a
configuration, crystal lattices may be misaligned at the interface
between the layers and consequently the structure may easily cause
a crack to advance in a direction parallel to the interface between
the layers, thus achieving an enhancement in the effect of
suppressing the penetration of cracks to the substrate. When, for
example, the first stack structure includes
(Al.sub.0.50Ti.sub.0.50)N layers and
(Al.sub.0.50Ti.sub.0.30Cr.sub.0.20)N layers, the comparison of the
metal elements present in these two kinds of layers shows that the
Al element and the Ti element are contained in the two layers while
the Cr element is present only in one of the layers. That is, the
above requirement is satisfied. Further, when the first stack
structure includes (Al.sub.0.50Cr.sub.0.50)N layers and
(Al.sub.0.67Ti.sub.0.33)N layers, the comparison of the metal
elements present in these two kinds of layers shows that the Al
element is contained in the two layers while the Cr element is
present only in one of the layers and the Ti element is present
only in the other of the layers. Thus, the above requirement is
satisfied.
[0062] Similarly, in the coated tool of the present invention, it
is more preferable that one layer constituting the second stack
structure and another layer constituting the second stack structure
which is adjacent to the one layer include one or more metal
elements different between the layers. With such a configuration,
crystal lattices may be misaligned at the interface between the
layers and consequently the structure may easily cause a crack to
advance in a direction parallel to the interface between the
layers, thus achieving an enhancement in the effect of suppressing
the penetration of cracks to the substrate.
[0063] In the coated tool of the present invention, the coating
layer includes the first stack structure having excellent fracture
resistance and the second stack structure having excellent wear
resistance. As a result, the coated tool exhibits excellent
fracture resistance and wear resistance. The coating layer may
include an upper layer on the surface of the coating layer on the
side opposite to the substrate through the first stack structure
and the second stack structure. Further, the coating layer may
include a lower layer at a closer side to the substrate than the
first and second stack structures. Furthermore, the coating layer
may include an intermediate layer between the first stack structure
and the second stack structure.
[0064] The configurations of these upper layers, intermediate
layers and lower layers are not particularly limited and any of
coating layers provided in coated tools may be used. In particular,
enhanced wear resistance may be advantageously obtained by adopting
a single layer configuration or a non-periodic multilayer
configuration including at least one selected from the group
consisting of a metal including at least one metal element selected
from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, Sr, Y, Sn and Bi;
and compounds including at least one of these metal elements and at
least one non-metal element selected from carbon, nitrogen, oxygen
and boron.
[0065] In a more preferred embodiment, the first stack structures
and the second stack structures are stacked alternately and
continuously each in two or more layers. With this configuration,
the structure may easily cause a crack to advance in a direction
parallel to the interface between the first stack structure and the
second stack structure, and thus effectively suppresses the
penetration of cracks to the substrate, namely, achieves enhanced
fracture resistance. The positional relationship between the first
stack structure and the second stack structure is not limited and
may be such that the first stack structure is closest to the
substrate and the second stack structure is closest to the surface
of the coating layer on the side opposite to the substrate or may
be such that the second stack structure is closest to the substrate
and the first stack structure is closest to the surface of the
coating layer on the side opposite to the substrate. Alternatively,
the first stack structure or the second stack structure may be
disposed closest to both the substrate and the surface of the
coating layer on the side opposite to the substrate. Based on the
fact that the residual compressive stress in the first stack
structure is lower than the residual compressive stress in the
second stack structure, it is more preferable that the first stack
structure be disposed closest to the substrate and the second stack
structure be disposed closest to the surface. In this case, the
coating layer tends to exhibit enhanced separation resistance.
[0066] The coating layer in the coated tool of the present
invention may be produced by any methods without limitation. For
example, a physical deposition method such as an ion plating
method, an arc ion plating method, a sputtering method or an ion
mixing method may be used to form layers such as the aforementioned
first stack structure and second stack structure onto the
substrate. In particular, the arc ion plating method is more
preferable because of excellent adhesion between the coating layer
and the substrate.
[0067] The coated tool of the present invention may be obtained by
forming the layers onto the surface of the substrate by a
conventional coating method. An exemplary production method is
described below.
[0068] A substrate processed into a shape of a tool is placed in a
reaction vessel of a physical deposition apparatus, and a vacuum is
produced by evacuating the inside of the reaction vessel to a
pressure of 1.times.10.sup.-2 Pa or below. After the vacuum has
been generated, the temperature of the substrate is raised to 200
to 800.degree. C. with a heater disposed in the reaction vessel.
After the heating, Ar gas is introduced into the reaction vessel to
raise the pressure to 0.5 to 5.0 Pa. In the Ar gas atmosphere at a
pressure of 0.5 to 5.0 Pa, a bias voltage of -200 to -1000 V is
applied to the substrate and a current of 5 to 20 A is passed
through a tungsten filament disposed in the reaction vessel,
thereby treating the surface of the substrate by ion bombardment of
the Ar gas. After the surface of the substrate has been treated by
ion bombardment, a vacuum is drawn to a pressure of
1.times.10.sup.-2 Pa or below.
[0069] Next, a reaction gas such as nitrogen gas is introduced into
the reaction vessel to increase the pressure inside the reaction
vessel to 0.5 to 5.0 Pa. A bias voltage of -10 to -150 V is applied
to the substrate, and metal deposition sources in accordance with
the metal components of the respective layers are vaporized by arc
discharge, thereby forming layers on the surface of the substrate.
In the case where two or more kinds of separately-arranged metal
deposition sources are vaporized at the same time by arc discharge
and layers for constituting the first stack structure or the second
stack structure are formed while rotating a rotatable table on
which the substrate has been fixed, the layer thicknesses of the
respective layers for constituting the first stack structure or the
second stack structure may be controlled by adjusting the
rotational speed of the rotatable table supporting the substrate in
the reaction vessel. When two or more kinds of metal deposition
sources are vaporized alternately by arc discharge to form layers
for constituting the first stack structure or the second stack
structure, the layer thicknesses of the respective layers for
constituting the first stack structure or the second stack
structure may be controlled by adjusting the arc discharge time for
the respective metal deposition sources.
[0070] The layer thicknesses of the respective layers constituting
the coating layer in the coated tool of the present invention may
be measured by analyzing the sectional structure of the coated tool
with a device such as an optical microscope, a scanning electron
microscope (SEM) or a transmission electron microscope (TEM). The
average layer thickness of each of the layers in the coated tool of
the present invention may be obtained by measuring the layer
thickness of each layer with respect to cross sections sampled from
3 or more regions approximately 50 .mu.m from the cutting edge of
the surface opposed to the metal deposition source toward the
center of the surface, and calculating the average value of the
obtained layer thicknesses.
[0071] The composition of each of the layers in the coated tool of
the present invention may be measured by analyzing the sectional
structure of the coated tool of the present invention with a device
such as an energy dispersive X-ray spectrometer (EDS) or a
wavelength dispersive X-ray spectrometer (WDS).
[0072] Specific examples of the coated tools of the present
invention include cutting inserts, drills and end mills.
EXAMPLES
Example 1
[0073] A cemented carbide corresponding to P10 in the shape of ISO
SEEN 1203 insert was provided as a substrate. Metal deposition
sources were arranged in a reaction vessel of an arc ion plating
apparatus so as to design layers having compositions described in
any of Tables 1 to 3. The substrate was fixed to a fixing hardware
of a rotatable table disposed in the reaction vessel.
[0074] Thereafter, a vacuum was produced by evacuating the inside
of the reaction vessel to a pressure of 5.0.times.10.sup.-3 Pa or
below. After the vacuum had been generated, the substrate was
heated to a temperature of 500.degree. C. with a heater disposed in
the reaction vessel. After the heating, Ar gas was introduced into
the reaction vessel to raise the pressure to 5.0 Pa.
[0075] In the Ar gas atmosphere at a pressure of 5.0 Pa, a bias
voltage of -1000 V was applied to the substrate and a current of 10
A was passed through a tungsten filament disposed in the reaction
vessel, thereby treating the surface of the substrate by ion
bombardment of the Ar gas for 30 minutes. After the completion of
the ion bombardment treatment, the inside of the reaction vessel
was evacuated to draw a vacuum to a pressure of 5.0.times.10.sup.-3
Pa or below.
[0076] After the vacuum had been produced, nitrogen gas was
introduced into the reaction vessel to create a nitrogen gas
atmosphere having a pressure of 2.7 Pa. A bias voltage of -50 V was
applied to the substrate, and an arc current of 200 A was passed to
produce arc discharge and thereby to vaporize the metal deposition
sources, thus forming the respective layers.
[0077] In the formation of Layers A1 and Layers B1 in Inventive
Products 1 to 11, the metal deposition source for Layers A1 and the
metal deposition source for Layers B1 were alternately vaporized by
arc discharge to form Layers A1 and Layers B1. During this process,
the layer thicknesses of Layers A1 and Layers B1 were controlled by
adjusting the respective arc discharge times. In the fabrication of
Comparative Product 1, Layers X and Layers Y with large layer
thicknesses were formed in the similar manner by alternately
vaporizing the metal deposition source for Layers X and the metal
deposition source for Layers Y by arc discharge. During this
process, the layer thicknesses of Layers X and Layers Y were
controlled by adjusting the respective arc discharge times.
[0078] In the formation of Layers A2 and Layers B2 in Inventive
Products 1 to 11, the metal deposition source for Layers A2 and the
metal deposition source for Layers B2 were simultaneously vaporized
by arc discharge to form Layers A2 and Layers B2. During this
process, the layer thicknesses of Layers A2 and Layers B2 were
controlled by adjusting the rotational speed of the rotatable table
in the range of 0.2 to 10 min.sup.-1. In the fabrication of
Comparative Product 2, Layers X and Layers Y with small layer
thicknesses were formed in the similar manner by simultaneously
vaporizing the metal deposition source for Layers X and the metal
deposition source for Layers Y by arc discharge. During this
process, the layer thicknesses of Layers X and Layers Y were
controlled by adjusting the rotational speed of the rotatable table
in the range of 0.2 to 10 min.sup.-1.
[0079] After the layers had been formed on the surface of the
substrate to the prescribed layer thicknesses, the heater was
turned off. After the sample temperature had decreased to
100.degree. C. or below, the sample was collected from the reaction
vessel.
TABLE-US-00001 TABLE 1 First stack structure Layers A1 + Layers B1
Second stack structure Layers A1 Layers B1 Average Layers A2
Average Average value of Average layer layer stacking Number of
Average layer Sample thickness thickness periods repetitions
thickness thickness No. Composition (nm) Composition (nm) T.sub.1
(nm) (times) (.mu.m) Composition (nm) Inv.
(Al.sub.0.50Ti.sub.0.50)N 100 (Al.sub.0.67Ti.sub.0.33)N 100 200 5
1.0 (Al.sub.0.50Ti.sub.0.50)N 10 Prod. 1 Inv.
(Al.sub.0.50Ti.sub.0.50)N 60 (Al.sub.0.67Ti.sub.0.33)N 60 120 10
1.2 (Al.sub.0.50Ti.sub.0.50)N 10 Prod. 2 Inv.
(Al.sub.0.50Ti.sub.0.50)N 250 (Al.sub.0.67Ti.sub.0.33)N 250 500 2
1.0 (Al.sub.0.50Ti.sub.0.50)N 10 Prod. 3 Inv.
(Al.sub.0.50Ti.sub.0.50)N 100 (Al.sub.0.67Ti.sub.0.33)N 100 200 10
2.0 (Al.sub.0.50Ti.sub.0.50)N 2 Prod. 4 Inv.
(Al.sub.0.50Ti.sub.0.50)N 100 (Al.sub.0.67Ti.sub.0.33)N 100 200 5
1.0 (Al.sub.0.50Ti.sub.0.50)N 45 Prod. 5 Inv.
(Al.sub.0.50Ti.sub.0.50)N 60 (Al.sub.0.67Ti.sub.0.33)N 60 120 3
0.36 (Al.sub.0.50Ti.sub.0.50)N 35 Prod. 6 Inv.
(Al.sub.0.50Ti.sub.0.50)N 250 (Al.sub.0.67Ti.sub.0.33)N 250 500 4
2.0 (Al.sub.0.50Ti.sub.0.50)N 2 Prod. 7 Inv.
(Al.sub.0.50Ti.sub.0.50)N 60 (Al.sub.0.67Ti.sub.0.33)N 60 120 3
0.36 (Al.sub.0.50Ti.sub.0.50)N 35 Prod. 8 Inv.
(Al.sub.0.50Ti.sub.0.50)N 250 (Al.sub.0.67Ti.sub.0.33)N 250 500 4
2.0 (Al.sub.0.50Ti.sub.0.50)N 2 Prod. 9 Inv.
(Al.sub.0.50Ti.sub.0.50)N 60 (Al.sub.0.67Ti.sub.0.33)N 60 120 3
0.36 (Al.sub.0.50Ti.sub.0.50)N 35 Prod. 10 Inv.
(Al.sub.0.50Ti.sub.0.50)N 250 (Al.sub.0.67Ti.sub.0.33)N 250 500 4
2.0 (Al.sub.0.50Ti.sub.0.50)N 2 Prod. 11 Second stack structure
Layers A2 + Layers B2 Layers B2 Average Average value of layer
stacking Number of Average Sample thickness periods repetitions
thickness T.sub.1 - T.sub.2 No. Composition (nm) T.sub.2 (nm)
(times) (.mu.m) (nm) Inv. (Al.sub.0.67Ti.sub.0.33)N 10 20 50 1.0
180 Prod. 1 Inv. (Al.sub.0.67Ti.sub.0.33)N 10 20 25 0.5 100 Prod. 2
Inv. (Al.sub.0.67Ti.sub.0.33)N 10 20 100 2.0 480 Prod. 3 Inv.
(Al.sub.0.67Ti.sub.0.33)N 2 4 100 0.4 196 Prod. 4 Inv.
(Al.sub.0.67Ti.sub.0.33)N 45 90 10 0.9 110 Prod. 5 Inv.
(Al.sub.0.67Ti.sub.0.33)N 35 70 30 2.1 50 Prod. 6 Inv.
(Al.sub.0.67Ti.sub.0.33)N 2 4 200 0.8 496 Prod. 7 Inv.
(Al.sub.0.67Ti.sub.0.33)N 35 70 30 2.1 50 Prod. 8 Inv.
(Al.sub.0.67Ti.sub.0.33)N 2 4 200 0.8 496 Prod. 9 Inv.
(Al.sub.0.67Ti.sub.0.33)N 35 70 30 2.1 50 Prod. 10 Inv.
(Al.sub.0.67Ti.sub.0.33)N 2 4 200 0.8 496 Prod. 11
TABLE-US-00002 TABLE 2 Coating layer First layer Fifth layer
(substrate side) Third layer (surface side) Lower layer Second
layer Intermediate layer Fourth layer Upper layer Total Average
Average Average Average Average layer Sample thick. Stack thick.
thick. Stack thick. thick. thick. No. Composition (.mu.m) structure
(.mu.m) Composition (.mu.m) structure (.mu.m) Composition (.mu.m)
(.mu.m) Inv. TiN 0.5 First 1.0 TiN 0.5 Second 1.0 TiN 0.5 3.5 Prod.
1 Inv. TiN 0.5 First 1.2 TiN 0.5 Second 0.5 TiN 0.5 3.2 Prod. 2
Inv. TiN 0.5 First 1.0 TiN 0.5 Second 2.0 TiN 0.5 4.5 Prod. 3 Inv.
TiN 0.5 First 2.0 TiN 0.5 Second 0.4 TiN 0.5 3.9 Prod. 4 Inv. TiN
0.5 First 1.0 TiN 0.5 Second 0.9 TiN 0.5 3.4 Prod. 5 Inv. TiN 0.5
First 0.36 TiN 0.5 Second 2.1 TiN 0.5 3.96 Prod. 6 Inv. TiN 0.5
First 2.0 TiN 0.5 Second 0.8 TiN 0.5 4.3 Prod. 7 Inv. (Ti.sub.0.60
Al.sub.0.40)N 0.5 First 0.36 (Ti.sub.0.60 Al.sub.0.40)N 0.5 Second
2.1 (Ti.sub.0.60 Al.sub.0.40)N 0.5 3.96 Prod. 8 Inv. (Ti.sub.0.60
Al.sub.0.40)N 0.5 First 2.0 (Ti.sub.0.60 Al.sub.0.40)N 0.5 Second
0.8 (Ti.sub.0.60 Al.sub.0.40)N 0.5 4.3 Prod. 9 Inv. (Ti.sub.0.85
Si.sub.0.15)N 0.5 First 0.36 (Ti.sub.0.85 Si.sub.0.15)N 0.5 Second
2.1 (Ti.sub.0.85 Si.sub.0.15)N 0.5 3.96 Prod. 10 Inv. (Ti.sub.0.85
Si.sub.0.15)N 0.5 First 2.0 (Ti.sub.0.85 Si.sub.0.15)N 0.5 Second
0.8 (Ti.sub.0.85 Si.sub.0.15)N 0.5 4.3 Prod. 11
*"First" and "Second" in the sections "Stacked structure" indicate
the first stack structure and the second stack structure in
Inventive Products with the corresponding numbers in Table 1.
TABLE-US-00003 TABLE 3 Coating layer Stack structure Layers X +
Layers Y Layers X Layers Y Average Average Average value of layer
layer stacking Number of Total layer Sample thickness thickness
periods repetitions thickness No. Composition (nm) Composition (nm)
T (nm) (times) (.mu.m) Comp. (Al.sub.0.50Ti.sub.0.50)N 100
(Al.sub.0.67Ti.sub.0.33)N 100 200 20 4.0 Prod. 1 Comp.
(Al.sub.0.50Ti.sub.0.50)N 10 (Al.sub.0.67Ti.sub.0.33)N 10 20 200
4.0 Prod. 2
[0080] The respective average layer thicknesses of the layers in
the samples obtained were determined by measuring the layer
thickness of each layer by TEM observation with respect to cross
sections sampled from 3 regions approximately 50 .mu.m from the
cutting edge of the surface of the coated tool opposed to the metal
deposition source toward the center of the surface, and calculating
the average value of the obtained layer thicknesses. The respective
compositions of the layers in the samples obtained were determined
by analyzing a cross section sampled from a region of from the
cutting edge of the surface of the coated tool opposed to the metal
deposition source to a distance of 50 .mu.m toward the center using
an EDS. The results are described in Tables 1 to 3. The
compositional ratios of the metal elements in the layers described
in Tables 1 to 3 indicate the atomic ratios of the metal elements
relative to the total of the metal elements in the metal compounds
forming the respective layers.
[0081] The fracture resistance of the samples obtained above was
evaluated by using the samples in face milling under the following
test conditions. The evaluation results are described in Table
4.
[0082] [Test Conditions]
[0083] Workpieces: SCM440
[0084] Workpiece shape: cuboid of 105 mm.times.200 mm.times.60 mm
(having 6 holes with a diameter of 30 mm in the 105 mm.times.200 mm
face to be milled of the cuboid)
[0085] Cutting rate: 250 m/min
[0086] Feed: 0.4 mm/tooth
[0087] Depth of cut: 2.0 mm
[0088] Cutting width: 105 mm
[0089] Coolant: none
[0090] Effective cutter diameter: 125 mm
[0091] Evaluation item: The length of cutting to the occurrence of
fracture of the sample (the occurrence of fracture in the cutting
blade of the sample) was measured.
TABLE-US-00004 TABLE 4 Length of Sample No. cutting (m) Inventive
Product 1 7.0 Inventive Product 2 6.2 Inventive Product 3 5.5
Inventive Product 4 6.9 Inventive Product 5 5.3 Inventive Product 6
4.7 Inventive Product 7 5.5 Inventive Product 8 4.8 Inventive
Product 9 6.5 Inventive Product 10 4.6 Inventive Product 11 5.3
Comparative Product 1 3.3 Comparative Product 2 3.6
[0092] The results in Table 4 show that Inventive Products achieved
a longer length of cutting and had a longer tool life than
Comparative Products which had an alternate stack structure
composed of layers with various uniform layer thicknesses.
Example 2
[0093] A cemented carbide corresponding to P10 in the shape of ISO
SEEN 1203 insert was provided as a substrate. Metal deposition
sources were arranged in a reaction vessel of an arc ion plating
apparatus so as to design layers having compositions described in
Table 5. Samples having layer configurations described in Tables 5
and 6 were fabricated by the same production method as in Example
1.
TABLE-US-00005 TABLE 5 First stack structure Layers A1 + Layers B1
Second stack structure Layers A1 Layers B1 Average Layers A2
Average Average value of Average layer layer stacking Number of
Average layer Sample thickness thickness periods repetitions
thickness thickness No. Composition (nm) Composition (nm) T.sub.1
(nm) (times) (.mu.m) Composition (nm) Inv.
(Al.sub.0.50Ti.sub.0.50)N 60 (Al.sub.0.67Ti.sub.0.33)N 60 120 5 0.6
(Al.sub.0.50Ti.sub.0.50)N 2 Prod. 12 Inv. (Al.sub.0.50Ti.sub.0.50)N
100 (Al.sub.0.67Ti.sub.0.33)N 100 200 10 2.0
(Al.sub.0.50Ti.sub.0.50)N 10 Prod. 13 Inv.
(Al.sub.0.50Ti.sub.0.50)N 250 (Al.sub.0.67Ti.sub.0.33)N 250 500 12
6.0 (Al.sub.0.50Ti.sub.0.50)N 10 Prod. 14 Inv.
(Al.sub.0.50Ti.sub.0.50)N 100 (Al.sub.0.67Ti.sub.0.33)N 100 200 5
1.0 (Al.sub.0.50Ti.sub.0.50)N 10 Prod. 15 Inv.
(Al.sub.0.50Ti.sub.0.50)N 60 (Al.sub.0.67Ti.sub.0.33)N 60 120 10
1.2 (Al.sub.0.50Ti.sub.0.50)N 10 Prod. 16 Inv.
(Al.sub.0.50Ti.sub.0.50)N 60 (Al.sub.0.67Ti.sub.0.33)N 60 120 10
1.2 (Al.sub.0.50Ti.sub.0.50)N 2 Prod. 17 Inv.
(Al.sub.0.50Ti.sub.0.50)N 250 (Al.sub.0.67Ti.sub.0.33)N 250 500 4
2.0 (Al.sub.0.50Ti.sub.0.50)N 10 Prod. 18 Inv.
(Al.sub.0.50Ti.sub.0.50)N 100 (Al.sub.0.67Ti.sub.0.33)N 100 200 5
1.0 (Al.sub.0.50Ti.sub.0.50)N 40 Prod. 19 Inv.
(Al.sub.0.50Ti.sub.0.50)N 100 (Al.sub.0.67Ti.sub.0.33)N 100 200 2
0.4 (Al.sub.0.50Ti.sub.0.50)N 10 Prod. 20 Inv.
(Al.sub.0.50Ti.sub.0.50)N 60 (Al.sub.0.67Ti.sub.0.33)N 60 120 10
1.2 (Al.sub.0.50Ti.sub.0.50)N 40 Prod. 21 Inv.
(Al.sub.0.50Ti.sub.0.50)N 250 (Al.sub.0.67Ti.sub.0.33)N 250 500 2
1.0 (Al.sub.0.50Ti.sub.0.50)N 2 Prod. 22 Second stack structure
Layers A2 + Layers B2 Layers B2 Average Average value of layer
stacking Number of Average Sample thickness periods repetitions
thickness T.sub.1 - T.sub.2 No. Composition (nm) T.sub.2 (nm)
(times) (.mu.m) (nm) Inv. (Al.sub.0.67Ti.sub.0.33)N 2 4 125 0.5 116
Prod. 12 Inv. (Al.sub.0.67Ti.sub.0.33)N 10 20 100 2.0 180 Prod. 13
Inv. (Al.sub.0.67Ti.sub.0.33)N 10 20 300 6.0 480 Prod. 14 Inv.
(Al.sub.0.67Ti.sub.0.33)N 10 20 50 1.0 180 Prod. 15 Inv.
(Al.sub.0.67Ti.sub.0.33)N 10 20 50 1.0 100 Prod. 16 Inv.
(Al.sub.0.67Ti.sub.0.33)N 2 4 250 1.0 116 Prod. 17 Inv.
(Al.sub.0.67Ti.sub.0.33)N 10 20 10 0.2 480 Prod. 18 Inv.
(Al.sub.0.67Ti.sub.0.33)N 40 80 13 1.04 120 Prod. 19 Inv.
(Al.sub.0.67Ti.sub.0.33)N 10 20 25 0.5 180 Prod. 20 Inv.
(Al.sub.0.67Ti.sub.0.33)N 40 80 5 0.4 40 Prod. 21 Inv.
(Al.sub.0.67Ti.sub.0.33)N 2 4 250 1.0 496 Prod. 22
TABLE-US-00006 TABLE 6 Coating layer First layer (substrate side)
Second layer Third layer Fourth layer Fifth layer Average Average
Average Average Average Sample Stack thick. Stack thick. Stack
thick. Stack thick. Stack thick. No structure (.mu.m) structure
(.mu.m) structure (.mu.m) structure (.mu.m) structure (.mu.m) Inv.
First 0.6 Second 0.5 -- -- -- -- -- -- Prod. 12 Inv. First 2.0
Second 2.0 -- -- -- -- -- -- Prod. 13 Inv. First 6.0 Second 6.0 --
-- -- -- -- -- Prod. 14 Inv. First 1.0 Second 1.0 First 1.0 Second
1.0 -- -- Prod. 15 Inv. First 1.2 Second 1.0 First 1.2 Second 1.0
-- -- Prod. 16 Inv. First 1.2 Second 1.0 First 1.2 Second 1.0 -- --
Prod. 17 Inv. First 2.0 Second 0.2 First 2.0 Second 0.2 -- -- Prod.
18 Inv. First 1.0 Second 1.04 First 1.0 Second 1.04 -- -- Prod. 19
Inv. First 0.4 Second 0.5 First 0.4 Second 0.5 First 0.4 Prod. 20
Inv. First 1.2 Second 0.4 First 1.2 Second 0.4 First 1.2 Prod. 21
Inv. First 1.0 Second 1.0 First 1.0 Second 1.0 First 1.0 Prod. 22
Coating layer Eighth layer Sixth layer Seventh layer (surface side)
Average Average Average Total layer Sample Stack thick. Stack
thick. Stack thick. thick. No structure (.mu.m) structure (.mu.m)
structure (.mu.m) (.mu.m) Inv. -- -- -- -- -- -- 1.1 Prod. 12 Inv.
-- -- -- -- -- -- 4.0 Prod. 13 Inv. -- -- -- -- -- -- 12.0 Prod. 14
Inv. -- -- -- -- -- -- 4.0 Prod. 15 Inv. -- -- -- -- -- -- 4.4
Prod. 16 Inv. -- -- -- -- -- -- 4.4 Prod. 17 Inv. -- -- -- -- -- --
4.4 Prod. 18 Inv. -- -- -- -- -- -- 4.08 Prod. 19 Inv. Second 0.5
-- -- -- -- 2.7 Prod. 20 Inv. Second 0.4 First 1.2 Second 0.4 6.4
Prod. 21 Inv. Second 1.0 First 1.0 Second 1.0 8.0 Prod. 22
*"First" and "Second" in the sections "Stacked structure" indicate
the first stack structure and the second stack structure in
Inventive Products with the corresponding numbers in Table 5.
[0094] The respective average layer thicknesses and the respective
compositions of the layers in the samples obtained were determined
in the same manner as in Example 1, the results being described in
Tables 5 and 6. Further, the fracture resistance of the samples
obtained was evaluated by using the samples in face milling under
the same test conditions as in Example 1. The evaluation results
are described in Table 7.
TABLE-US-00007 TABLE 7 Length of Sample No. cutting (m) Inventive
Product 12 7.5 Inventive Product 13 9.1 Inventive Product 14 6.6
Inventive Product 15 9.2 Inventive Product 16 8.8 Inventive Product
17 9.1 Inventive Product 18 6.6 Inventive Product 19 7.5 Inventive
Product 20 7.8 Inventive Product 21 7.2 Inventive Product 22 6.6
Comparative Product 1 3.3 Comparative Product 2 3.6
[0095] From Table 7, it has been shown that Inventive Products
achieved a longer length of cutting and had a longer tool life than
Comparative Products which had an alternate stack structure
composed of layers with various uniform layer thicknesses.
Example 3
[0096] A cemented carbide corresponding to P10 in the shape of ISO
SEEN 1203 insert was provided as a substrate. In the fabrication of
Inventive Products 23 and 25 to 35 and Comparative Products 3 and 5
to 15, metal deposition sources were arranged in a reaction vessel
of an arc ion plating apparatus so as to design layers having
compositions described in Tables 8 and 10, and samples having layer
configurations described in Tables 9 and 10 were fabricated by the
same production method as in Example 1.
[0097] In the fabrication of Inventive Product 24 and Comparative
Product 4, metal deposition sources were arranged in a reaction
vessel of an arc ion plating apparatus so as to design layers
having compositions described in Tables 8 and 10, and samples
having layer configurations described in Tables 9 and 10 were
fabricated in the same manner as in Example 1 except that the
atmosphere in the reaction vessel during the formation of layers
was created by feeding a mixed gas containing N.sub.2 gas and
CH.sub.4 gas in a partial pressure ratio N.sub.2:CH.sub.4=1:1 to a
pressure inside the reaction vessel of 2.7 Pa.
TABLE-US-00008 TABLE 8 First stack structure Layers A1 + Layers B1
Second stack structure Layers A1 Layers B1 Average Layers A2
Average Average value of Average layer layer stacking Number of
Average layer Sample thickness thickness periods repetitions
thickness thickness No. Composition (nm) Composition (nm) T.sub.1
(nm) (times) (.mu.m) Composition (nm) Inv.
(Al.sub.0.50Ti.sub.0.50)N 100 (Al.sub.0.60Ti.sub.0.40)N 100 200 5
1.0 (Al.sub.0.50Ti.sub.0.50)N 10 Prod. 23 Inv.
(Al.sub.0.50Ti.sub.0.50)CN 100 (Al.sub.0.67Ti.sub.0.33)CN 100 200 5
1.0 (Al.sub.0.50Ti.sub.0.50)CN 10 Prod. 24 Inv.
(Al.sub.0.50Ti.sub.0.50)N 100 (Al.sub.0.45Ti.sub.0.45Si.sub.0.10)N
100 200 5 1.0 (Al.sub.0.50Ti.sub.0.50)N 10 Prod. 25 Inv.
(Al.sub.0.50Ti.sub.0.50)N 100 (Al.sub.0.45Ti.sub.0.45Sr.sub.0.10)N
100 200 5 1.0 (Al.sub.0.50Ti.sub.0.50)N 10 Prod. 26 Inv.
(Al.sub.0.50Ti.sub.0.50)N 100 (Al.sub.0.45Ti.sub.0.45Y.sub.0.10)N
100 200 5 1.0 (Al.sub.0.50Ti.sub.0.50)N 10 Prod. 27 Inv.
(Al.sub.0.50Ti.sub.0.50)N 100 (Al.sub.0.50Ti.sub.0.30Cr.sub.0.20)N
100 200 5 1.0 (Al.sub.0.50Ti.sub.0.50)N 10 Prod. 28 Inv.
(Al.sub.0.50Ti.sub.0.50)N 100 (Al.sub.0.50Ti.sub.0.45Nb.sub.0.05)N
100 200 5 1.0 (Al.sub.0.50Ti.sub.0.50)N 10 Prod. 29 Inv.
(Al.sub.0.50Ti.sub.0.50)N 100 (Al.sub.0.50Ti.sub.0.45Ta.sub.0.05)N
100 200 5 1.0 (Al.sub.0.50Ti.sub.0.50)N 10 Prod. 30 Inv.
(Al.sub.0.50Ti.sub.0.50)N 100 (Al.sub.0.50Ti.sub.0.45W.sub.0.05)N
100 200 5 1.0 (Al.sub.0.50Ti.sub.0.50)N 10 Prod. 31 Inv.
(Al.sub.0.50Cr.sub.0.50)N 100 (Al.sub.0.67Ti.sub.0.33)N 100 200 5
1.0 (Al.sub.0.50Cr.sub.0.50)N 10 Prod. 32 Inv.
(Al.sub.0.50Cr.sub.0.50)N 100 (Ti.sub.0.90Si.sub.0.10)N 100 200 5
1.0 (Al.sub.0.50Cr.sub.0.50)N 10 Prod. 33 Inv.
(Ti.sub.0.50Cr.sub.0.50)N 100 (Al.sub.0.67Ti.sub.0.33)N 100 200 5
1.0 (Ti.sub.0.50Cr.sub.0.50)N 10 Prod. 34 Inv.
(Ti.sub.0.50Cr.sub.0.50)N 100 (Ti.sub.0.90Si.sub.0.10)N 100 200 5
1.0 (Ti.sub.0.50Cr.sub.0.50)N 10 Prod. 35 Second stack structure
Layers A2 + Layers B2 Layers B2 Average Average value of layer
stacking Number of Average Sample thickness periods repetitions
thickness T.sub.1 - T.sub.2 No. Composition (nm) T.sub.2 (nm)
(times) (.mu.m) (nm) Inv. (Al.sub.0.60Ti.sub.0.40)N 10 20 50 1.0
180 Prod. 23 Inv. (Al.sub.0.67Ti.sub.0.33)CN 10 20 50 1.0 180 Prod.
24 Inv. (Al.sub.0.45Ti.sub.0.45Si.sub.0.10)N 10 20 50 1.0 180 Prod.
25 Inv. (Al.sub.0.45Ti.sub.0.45Sr.sub.0.10)N 10 20 50 1.0 180 Prod.
26 Inv. (Al.sub.0.45Ti.sub.0.45Y.sub.0.10)N 10 20 50 1.0 180 Prod.
27 Inv. (Al.sub.0.50Ti.sub.0.30Cr.sub.0.20)N 10 20 50 1.0 180 Prod.
28 Inv. (Al.sub.0.50Ti.sub.0.45Nb.sub.0.05)N 10 20 50 1.0 180 Prod.
29 Inv. (Al.sub.0.50Ti.sub.0.45Ta.sub.0.05)N 10 20 50 1.0 180 Prod.
30 Inv. (Al.sub.0.50Ti.sub.0.45W.sub.0.05)N 10 20 50 1.0 180 Prod.
31 Inv. (Al.sub.0.67Ti.sub.0.33)N 10 20 50 1.0 180 Prod. 32 Inv.
(Ti.sub.0.90Si.sub.0.10)N 10 20 50 1.0 180 Prod. 33 Inv.
(Al.sub.0.67Ti.sub.0.33)N 10 20 50 1.0 180 Prod. 34 Inv.
(Ti.sub.0.90Si.sub.0.10)N 10 20 50 1.0 180 Prod. 35
TABLE-US-00009 TABLE 9 Coating layer First layer Fourth layer
(substrate side) Second layer Third layer (surface side) Average
Average Average Average Total layer Sample Stack thick. Stack
thick. Stack thick. Stack thick. thickness No. structure (.mu.m)
structure (.mu.m) structure (.mu.m) structure (.mu.m) (.mu.m) Inv.
First 1.0 Second 1.0 First 1.0 Second 1.0 4.0 Prod. 23 Inv. First
1.0 Second 1.0 First 1.0 Second 1.0 4.0 Prod. 24 Inv. First 1.0
Second 1.0 First 1.0 Second 1.0 4.0 Prod. 25 Inv. First 1.0 Second
1.0 First 1.0 Second 1.0 4.0 Prod. 26 Inv. First 1.0 Second 1.0
First 1.0 Second 1.0 4.0 Prod. 27 Inv. First 1.0 Second 1.0 First
1.0 Second 1.0 4.0 Prod. 28 Inv. First 1.0 Second 1.0 First 1.0
Second 1.0 4.0 Prod. 29 Inv. First 1.0 Second 1.0 First 1.0 Second
1.0 4.0 Prod. 30 Inv. First 1.0 Second 1.0 First 1.0 Second 1.0 4.0
Prod. 31 Inv. First 1.0 Second 1.0 First 1.0 Second 1.0 4.0 Prod.
32 Inv. First 1.0 Second 1.0 First 1.0 Second 1.0 4.0 Prod. 33 Inv.
First 1.0 Second 1.0 First 1.0 Second 1.0 4.0 Prod. 34 Inv. First
1.0 Second 1.0 First 1.0 Second 1.0 4.0 Prod. 35
*"First" and "Second" in the sections "Stacked structure" indicate
the first stack structure and the second stack structure in
Inventive Products with the corresponding numbers in Table 8.
TABLE-US-00010 TABLE 10 Coating layer Stack structure Layers X +
Layers Y Layers X Layers Y Average Average Average value of layer
layer stacking Number of Total layer Sample thickness thickness
periods repetitions thickness No. Composition (nm) Composition (nm)
T (nm) (times) (.mu.m) Comp. (Al.sub.0.50Ti.sub.0.50)N 10
(Al.sub.0.60Ti.sub.0.40)N 10 20 200 4.0 Prod. 3 Comp.
(Al.sub.0.50Ti.sub.0.50)CN 10 (Al.sub.0.67Ti.sub.0.33)CN 10 20 200
4.0 Prod. 4 Comp. (Al.sub.0.50Ti.sub.0.50)N 10
(Al.sub.0.45Ti.sub.0.45Si.sub.0.10)N 10 20 200 4.0 Prod. 5 Comp.
(Al.sub.0.50Ti.sub.0.50)N 10 (Al.sub.0.45Ti.sub.0.45Sr.sub.0.10)N
10 20 200 4.0 Prod. 6 Comp. (Al.sub.0.50Ti.sub.0.50)N 10
(Al.sub.0.45Ti.sub.0.45Y.sub.0.10)N 10 20 200 4.0 Prod. 7 Comp.
(Al.sub.0.50Ti.sub.0.50)N 10 (Al.sub.0.50Ti.sub.0.30Cr.sub.0.20)N
10 20 200 4.0 Prod. 8 Comp. (Al.sub.0.50Ti.sub.0.50)N 10
(Al.sub.0.50Ti.sub.0.45Nb.sub.0.05)N 10 20 200 4.0 Prod. 9 Comp.
(Al.sub.0.50Ti.sub.0.50)N 10 (Al.sub.0.50Ti.sub.0.45Ta.sub.0.05)N
10 20 200 4.0 Prod. 10 Comp. (Al.sub.0.50Ti.sub.0.50)N 10
(Al.sub.0.50Ti.sub.0.45W.sub.0.05)N 10 20 200 4.0 Prod. 11 Comp.
(Al.sub.0.50Cr.sub.0.50)N 10 (Al.sub.0.67Ti.sub.0.33)N 10 20 200
4.0 Prod. 12 Comp. (Al.sub.0.50Cr.sub.0.50)N 10
(Ti.sub.0.90Si.sub.0.10)N 10 20 200 4.0 Prod. 13 Comp.
(Ti.sub.0.50Cr.sub.0.50)N 10 (Al.sub.0.67Ti.sub.0.33)N 10 20 200
4.0 Prod. 14 Comp. (Ti.sub.0.50Cr.sub.0.50)N 10
(Ti.sub.0.90Si.sub.0.10)N 10 20 200 4.0 Prod. 15
[0098] The respective layer thicknesses and the respective
compositions of the layers in the samples obtained were determined
in the same manner as in Example 1, the results being described in
Tables 8 to 10. The compositional ratios of the metal elements in
the layers described in Tables 8 and 10 indicate the atomic ratios
of the metal elements relative to the total of the metal elements
in the metal compounds forming the respective layers. The fracture
resistance of the samples obtained was evaluated by using the
samples in face milling under the same test conditions as in
Example 1. The evaluation results are described in Tables 11 and
12.
TABLE-US-00011 TABLE 11 Length of Sample No. cutting (m) Inventive
Product 23 9.1 Inventive Product 24 8.8 Inventive Product 25 8.8
Inventive Product 26 8.7 Inventive Product 27 8.8 Inventive Product
28 9.0 Inventive Product 29 8.8 Inventive Product 30 8.8 Inventive
Product 31 9.0 Inventive Product 32 9.0 Inventive Product 33 8.6
Inventive Product 34 9.0 Inventive Product 35 8.6
TABLE-US-00012 TABLE 12 Length of Sample No. cutting (m)
Comparative Product 3 3.5 Comparative Product 4 3.3 Comparative
Product 5 3.3 Comparative Product 6 3.1 Comparative Product 7 3.2
Comparative Product 8 3.4 Comparative Product 9 3.3 Comparative
Product 10 3.3 Comparative Product 11 3.4 Comparative Product 12
3.4 Comparative Product 13 3.0 Comparative Product 14 3.4
Comparative Product 15 3.0
[0099] From Tables 11 and 12, it has been shown that Inventive
Products achieved a longer length of cutting and had a longer tool
life than Comparative Products which had an alternate stack
structure composed of layers with various uniform layer
thicknesses.
REFERENCE SIGNS LIST
[0100] 1 Substrate [0101] 2 Coating layer [0102] 3 First stack
structure [0103] 4 Second stack structure [0104] 5 Layer A1 [0105]
6 Layer B1 [0106] 7 Layer A2 [0107] 8 Layer B2
* * * * *