U.S. patent application number 15/512712 was filed with the patent office on 2017-10-12 for laminated hard coating and molding die.
This patent application is currently assigned to Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.). The applicant listed for this patent is Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.). Invention is credited to Kenji YAMAMOTO.
Application Number | 20170291211 15/512712 |
Document ID | / |
Family ID | 55803944 |
Filed Date | 2017-10-12 |
United States Patent
Application |
20170291211 |
Kind Code |
A1 |
YAMAMOTO; Kenji |
October 12, 2017 |
LAMINATED HARD COATING AND MOLDING DIE
Abstract
A laminated hard film is obtained by laminating a layer A and a
layer B. The layer A has a composition different from that of the
layer B. The layer A is formed of
(Ti.sub.aCr.sub.bAl.sub.cSi.sub.d)(C.sub.xN.sub.1-x) and satisifies
the relationship of 0.ltoreq.a.ltoreq.0.10,
0.10.ltoreq.b.ltoreq.0.50, 0.50.ltoreq.c.ltoreq.0.90,
0.ltoreq.d.ltoreq.0.05, a+b+c+d=1 and 0.ltoreq.x.ltoreq.0.5. The
layer B is formed of (Cr.sub.eSi.sub.1-e)(C.sub.yN.sub.1-y) and
satisfies the relationship of 0.90.ltoreq.e.ltoreq.1.0 and
0.ltoreq.y.ltoreq.0.5, or is formed of
(Al.sub.fSi.sub.1-f)(C.sub.2N.sub.1-z) and satisfies the
relationship of 0.90.ltoreq.f.ltoreq.1.0 and 0.ltoreq.x.ltoreq.0.5.
Each of the layer A and the layer B has a thickness of 2 to 100 nm,
and the layer A and the layer B are each alternately laminated.
Inventors: |
YAMAMOTO; Kenji; (Hyogo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) |
Kobe-shi |
|
JP |
|
|
Assignee: |
Kabushiki Kaisha Kobe Seiko Sho
(Kobe Steel, Ltd.)
Kobe-shi
JP
|
Family ID: |
55803944 |
Appl. No.: |
15/512712 |
Filed: |
September 15, 2015 |
PCT Filed: |
September 15, 2015 |
PCT NO: |
PCT/JP2015/076204 |
371 Date: |
March 20, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C23C 14/0641 20130101;
B21D 37/01 20130101; C23C 14/0664 20130101; C23C 14/32 20130101;
C23C 28/42 20130101; C23C 28/042 20130101; B21D 22/022 20130101;
B21D 37/10 20130101; C23C 28/044 20130101; C23C 14/024
20130101 |
International
Class: |
B21D 37/01 20060101
B21D037/01; B21D 37/10 20060101 B21D037/10; B21D 22/02 20060101
B21D022/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 24, 2014 |
JP |
2014-193885 |
Dec 26, 2014 |
JP |
2014-266487 |
Claims
1. A laminated hard film obtained by laminating a layer A and a
layer B, the layer A having a composition different from that of
the layer B, wherein the layer A is formed of
(Ti.sub.aCr.sub.bAl.sub.cSi.sub.d)(C.sub.xN.sub.1-x) and satisfies
the relationship of 0.ltoreq.a.ltoreq.0.10,
0.10.ltoreq.b.ltoreq.0.50, 0.50.ltoreq.c.ltoreq.0.90,
0.ltoreq.d.ltoreq.0.05, a+b+c+d=1 and 0.ltoreq.x.ltoreq.0.5, when
atomic ratios of Ti, Cr, Al, Si and C are defined as a, b, c, d and
x, respectively, the layer B is formed of (Cr.sub.eSi.sub.1-e)
(C.sub.yN.sub.1-y) and satisfies the relationship of
0.90.ltoreq.e.ltoreq.1.0 and 0.ltoreq.y.ltoreq.0.5, when atomic
ratios of Cr and C are defined as e and y, respectively, or is
formed of (Al.sub.fSi.sub.1-f)(C.sub.zN.sub.1-z) and satisfies the
relationship of 0.90.ltoreq.f.ltoreq.1.0 and 0.ltoreq.y.ltoreq.0.5,
when atomic ratios of Al and C are defined as f and z,
respectively, and each of the layer A and the layer B has a
thickness of 2 to 100 nm, and the layer A and the layer B are each
alternately laminated.
2. The laminated hard film according to claim 1, wherein the atomic
ratio of Al to a total of Ti, Cr, Al and Si in the layer A and the
layer B falls within a range of 020 to 0.60.
3. The laminated hard film according to claim 1, wherein Ti in the
layer A is at least partially substituted with Zr.
4. A molding die comprising the laminated hard film according to
claim 1, a substrate surface.
5. A molding die comprising the laminated hard film according to
claim 3, a substrate surface.
6. The molding die according to claim 4, comprising an intermediate
layer of CrN having a thickness of 3 to 10 .mu.m between the
laminated hard film and the substrate.
7. The molding die according to claim 5, comprising an intermediate
layer of CrN having a thickness of 3 to 10 .mu.m between the
laminated hard film and the substrate.
8. The molding die according to claim 6, which is suitable for hot
forming of a steel material.
9. The molding die according to claim 7, which is suitable for hot
forming of a steel material.
10. The laminated hard film according to claim 2, wherein Ti in the
layer A is at least partially substituted with Zr.
11. A molding die comprising the laminated hard film according to
claim 2 on a substrate surface.
12. A molding die comprising the laminated hard film according to
claim 10 on a substrate surface.
13. The molding die according to claim 11, comprising an
intermediate layer of CrN having a thickness of 3 to 10 .mu.m
between the laminated hard film and the substrate.
14. The molding die according to claim 12, comprising an
intermediate layer of CrN having a thickness of 3 to 10 .mu.m
between the laminated hard film and the substrate.
15. The molding die according to claim 13, which is suitable for
hot forming of a steel material.
16. The molding die according to claim 14, which is suitable for
hot forming of a steel material.
Description
TECHNICAL FIELD
[0001] The present invention relates to a laminated hard film
exerting excellent wear resistance and toughness, and a molding die
including the above laminated hard film on/above a substrate
surface.
BACKGROUND ART
[0002] A substrate surface has hitherto been coated with a hard
film of TiN, TiCN, TiAlN or the like for the purpose of improving
wear resistance of a jig and tool having a cemented carbide, a
cermet, a high-speed tool steel, an alloy tool steel or the like as
a substrate. However, with an increase in hardness of workpiece
materials or an increase in cutting speed, it has been demanded to
realize a hard film further increased in wear resistance.
[0003] The present inventors have proposed a hard film formed by
laminating film layers satisfying predetermined composition ratios
on/above a substrate surface of a die for forming a steel material
represented by high-tensile steel, for example, as shown in Patent
Literature 1.
[0004] Through the development of the above technique, it has
become possible to realize the hard film more excellent in wear
resistance and oxidation resistance than a hard film formed of a
monolayer of TiN, TiCN, TiAlN or the like, which has hitherto been
used. However, it has been desired to realize a hard film increased
in toughness and further improved in durability.
PRIOR ART LITERATURE
Patent Literature
[0005] Patent Literature 1: Japanese Patent No. 4668214
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0006] The present invention has been made in view of the
circumstances as described above, and an object thereof is to
provide: a laminated hard film further improved in wear resistance
and toughness; and a molding die.
Means for Solving the Problems
[0007] The laminated hard film which could solve the above
problem(s) is a laminated hard film obtained by laminating a layer
A and a layer B, the layer A having a composition different from
that of the layer B, wherein
[0008] the layer A is formed of
(Ti.sub.aCr.sub.bAl.sub.cSi.sub.d)(C.sub.xN.sub.1-x) and satisfies
the relationship of 0.ltoreq.a.ltoreq.0.10,
0.10.ltoreq.b.ltoreq.0.50, 0.50.ltoreq.c.ltoreq.0.90,
0.ltoreq.d.ltoreq.0.05, a+b+c+d=1 and 0.ltoreq.x.ltoreq.0.5, when
atomic ratios of Ti, Cr, Al, Si and C are defined as a, b, c, d and
x, respectively,
[0009] the layer B is formed of (Cr.sub.eSi.sub.1-e)
(C.sub.yN.sub.1-y) and satisfies the relationship of
0.90.ltoreq.e.ltoreq.1.0 and 0.ltoreq.y.ltoreq.0.5, when atomic
ratios of Cr and C are defined as e and y, respectively, or is
fomied of (Al.sub.fSi.sub.1-f)(C.sub.zN.sub.1-z) and satisfies the
relationship of 0.90.ltoreq.f.ltoreq.1.0 and 0.ltoreq.z.ltoreq.0.5,
when atomic ratios of Al and C are defined as f and z,
respectively, and
[0010] each of the layer A and the layer B has a thickness of 2 to
100 nm, and the layer A and the layer B are each alternately
laminated.
[0011] It is preferred that the atomic ratio of Al to a total of
Ti, Cr, Al and Si in the layer A and the layer B falls within a
range of 0.20 to 0.60.
[0012] In the laminated hard film of the present invention, it is
also preferable that Ti in the layer A is at least partially
substituted with Zr.
[0013] The molding die further improved in wear resistance and
toughness can be realized by including the laminated hard film as
described above on/a.bove a substrate surface. In the above molding
die, a molding die including an inteimediate layer of CrN having a
thickness of 3 to 10 .mu.m between the above laminated hard film
and the above substrate is also preferred. Further, such a molding
die exerts excellent properties, not only at room temperature, but
also at a high temperature of about 400 to 500.degree. C., so that
it is particularly useful as a die to be used for hot forming of a
steel material.
Advantageous Effects of the Invention
[0014] In the present invention, the wear resistance and toughness
can be more improved than the conventional monolayer hard film by
using a laminated hard film in which layer(s) A showing good wear
resistance and layer(s) B showing high toughness are alternately
laminated.
Modes for Carrying Out the Invention
[0015] The hard film of the present invention is a laminated hard
film in which layer(s) A showing good wear resistance and layer(s)
B showing high toughness are alternately laminated.
[0016] The layer(s) A constituting the laminated hard film are
formed of (Ti.sub.aCr.sub.bAl.sub.cSi.sub.d)(C.sub.xN.sub.1-x) and
satisfy the following relationship, when the atomic ratios of Ti,
Cr, Al, Si and C are defined as a, b, c, d and x, respectively.
[0017] 0.ltoreq.a.ltoreq.0.10, 0.10.ltoreq.b.ltoreq.0.50,
0.50.ltoreq.c.ltoreq.0.90, 0.ltoreq.d.ltoreq.0.05, a+b+c+d=1,
0.ltoreq.x.ltoreq.0.5
[0018] The above layer(s) A contain a predetermined amount of Al,
thereby exerting wear resistance excellent in sliding properties
with a steel material, particularly in a hot forming region where
the temperature becomes high, during forming of the steel material
on a surface of which scales have been formed. In order to allow
such properties to be exerted, the atomic ratio of Al is 0.50 or
more, that is, the value of c is necessary to be 0.50 or more, when
the total of the atomic ratios of metal elements of Ti, Cr, Al and
Si in the layer(s) A indicated by
(Ti.sub.aCr.sub.bAl.sub.cSi.sub.d)(C.sub.xN.sub.1-x) is a+b+c+d=1.
The value of c is preferably 0.60 or more, and more preferably 0.65
or more.
[0019] However, when the Al amount is excessive, the wear
resistance and the toughness are deteriorated. Therefore, the
atomic ratio of Al or the value of c is necessary to be 0.90 or
less. The value of c is preferably 0.85 or less, and more
preferably 0.80 or less.
[0020] Ti in the above layer(s) A may not be contained in the film.
However, by allowing Ti to be contained, the hardness of the film
is increased to further improve the wear resistance. From such a
viewpoint, the atomic ratio of Ti or the value of a is preferably
0.01 or more, and more preferably 0.02 or more. However, when the
Ti amount is excessive, the oxidation resistance of the layer(s) A
is decreased, particularly during hot forming. Therefore, the
atomic ratio of Ti or the value of a is necessary to be 0.10 or
less. The value of a is preferably 0.08 or less, and more
preferably 0.05 or less.
[0021] Cr in the above layer(s) A increases the hardness of the
film to improve the wear resistance. From such a viewpoint, the
atomic ratio of Cr or the value of b is necessary to be 0.10 or
more. The value of b is preferably 0.15 or more, and more
preferably 0.20 or more. However, when the Cr amount is excessive,
the oxidation resistance of the layer(s) A is decreased. Therefore,
the atomic ratio of Cr or the value of b is necessary to be 0.50 or
less. The value of b is preferably 0.45 or less, and more
preferably 0.40 or less.
[0022] A metal element other than Ti, Cr and Al in the above
layer(s) A is Si. Si is an element effective for increasing the
hardness of the film to improve the wear resistance, and is
contained as needed. From such a viewpoint, the atomic ratio of Si
or the value of d is preferably 0.01 or more, and more preferably
0.02 or more. However, when the Si amount is excessive, the
oxidation resistance of the layers A is decreased. Therefore, the
atomic ratio of Si or the value of d is necessary to be 0.05 or
less. The value of d is preferably 0.04 or less, and more
preferably 0.03 or less.
[0023] The above layer(s) A are basically based on a nitride. That
is, the layer(s) A indicated by
(Ti.sub.aCr.sub.bAl.sub.cSi.sub.d)(C.sub.xN.sub.1-x) are a nitride
in the case of x=0. However, carbon C is sometimes contained as an
impurity in the film, and in this case, a carbide is partially
formed. However, when the C amount is excessive to increase the
carbide amount, the wear resistance of the layer(s) A is decreased.
From such a viewpoint, the atomic ratio of C or the value of x is
necessary to be 0.5 or less. The value of x is preferably 0.3 or
less, and more preferably 0.1 or less.
[0024] On the other hand, the layer(s) B constituting the laminated
hard film of the present invention are
[0025] formed of (Cr.sub.eSi.sub.1-f) (C.sub.yN.sub.1-y) and
satisfy the following relationship, when the atomic ratios of Cr
and C are defined as e and y, respectively,
0.90.ltoreq.e.ltoreq.1.0, 0.ltoreq.y.ltoreq.0.5 or formed of
(Al.sub.fSi.sub.1-f)(C.sub.zN.sub.1-z) and satisfy the following
relationship, when the atomic ratios of Al and C are defined as f
and z, respectively.
[0026] 0.90.ltoreq.f.ltoreq.1.0, 0.ltoreq.z.ltoreq.0.5
[0027] The above layer(s) B contain Cr or Al as a metal element, so
that the layer(s) B show high toughness. Specifically, the layer(s)
B exert such a property that chipping of the film is less likely to
occur under high load. In order to allow the property to be
exerted, the atomic ratios of Cr and Al or the values of e and f
are both necessary to be 0.90 or more. The values of e and fare
both preferably 0.93 or more, and more preferably 0.95 or more.
[0028] Although the above layer(s) B may be formed of only Cr or
Al, Cr or Al may be partially substituted with Si. Si is an element
effective for increasing the hardness of the film to improve the
wear resistance, and is contained as needed. However, when the Si
amount is excessive, the content of Cr or Al is relatively
insufficient, resulting in a decrease in the toughness of the
layer(s) B and a decrease in the hardness to cause a decrease in
the wear resistance. Therefore, the atomic ratio of Si or the value
of 1-e or 1-f is necessary to be 0.10 or less. The value of 1-e or
1-f is preferably 0.07 or less, and more preferably 0.05 or
less.
[0029] As with the above layer(s) A, the above layer(s) B are
basically based on a nitride. That is, the layer(s) B indicated by
(Cr.sub.eSi.sub.1-f) (C.sub.yN.sub.1-y) or
(Al.sub.fSi.sub.1-f)(C.sub.zN.sub.1-z) are a nitride in the case of
y=0 or z=0. However, carbon C is sometimes contained as an impurity
in the film, and in this case, a carbide is partially formed.
However, when the C amount is excessive to increase the carbide
amount, the toughness of the layer(s) B is decreased. From such a
viewpoint, the atomic ratio of C or the value of y or z is
necessary to be 0.5 or less. The value of y or z is preferably 0.3
or less, and more preferably 0.1 or less.
[0030] As described above, the hard film having both the excellent
wear resistance and toughness can be realized by alternately
laminating the layer(s) A excellent in the wear resistance and the
layer(s) B excellent in the toughness. In order to allow the
function of each of the above layer(s) A and layer(s) B to be
effectively exerted, the layer(s) A and the layer(s) B are
necessary to be alternately laminated as independent layer(s), not
in a state where compositions of the layer(s) A and the layer(s) B
are mixed. From such a viewpoint, the thickness of each of the
layer(s) A and the layer(s) B is necessary to be 2 nm or more. The
thickness of each of the layer(s) A and the layer(s) B is
preferably 5 nm or more, and more preferably 10 nm or more.
[0031] However, an excessive increase in the thickness of each of
the layer(s) A and the layer(s) B causes deterioration of
properties, particularly the wear resistance, when laminated. From
such a viewpoint, the thickness of each of the layer(s) A and the
layer(s) B is necessary to be 100 nm or less. The thickness of each
of the layer(s) A and the layer(s) B is preferably 50 nm or less,
more preferably 40 nm or less, still more preferably 30 nm or less,
and particularly preferably 20 nm or less.
[0032] The thickness of the layer A and that of the layer B are not
necessarily the same with each other. For example, the thickness of
the layer A is 20 nm, and the thickness of the layer B may be
changed between 2 to 100 nm. Further, the layer(s) B are not
necessarily disposed on the substrate side, and the layer(s) A may
be present on the substrate side. Furthermore, a film structure
that the layer(s) A or the layer(s) B which are present on the
substrate side are present on the uppermost surface side may be
used, and various laminated structures may be adopted depending on
the purpose. In addition, such a structure that CrSiCN and AlSiCN
are used as the layer(s) B and laminated on the layer(s) A,
specifically "layer A/Bl(CrSiCN)/layer A/layer B (AlSiCN)/layer A .
. . ", may also be adopted,
[0033] The thickness of the whole laminated hard film or the total
thickness is not limited in any way. However, in order to allow the
properties of the present invention to be effectively exerted, the
total thickness of the film is preferably 1 .mu.m (1,000 nm) or
more, and more preferably 2 .mu.m (2,000 nm) or more. However, an
excessive increase in the total thickness of the film causes
deterioration of the toughness of the film. Therefore, it is
preferably 20 .mu.m (20,000 nm) or less, more preferably 10 .mu.m
(10,000 nm) or less, and still more preferably 8 .mu.m (8,000 nm)
or less. The number of times of laminating of the layers A and the
layers B is recommended to be properly controlled so as to satisfy
the preferred total thickness described above.
[0034] Also, in order to maximize the functions of both layers A
and B in the laminated state, the number of times of laminating is
preferably plural, i.e. 2 or more. From such a viewpoint, it is
preferred to make the thickness of each of the layer(s) A and the
layer(s) B as thin as possible and to make the number of times of
laminating plural. The number of times of laminating as used herein
is the value determined, when defining the laminating of the layer
A and the layer B as that the number of times of laminating is
1.
[0035] The ratios of the elements in each layer of the layer(s) A
and the layer(s) B are as described above. However, in the present
invention, it has been found that the atomic ratio of Al to the
total of the metal elements in the layer(s) A and the layer(s) B,
that is, the total of Ti, Cr, Al and Si in the layer(s) A and the
layer(s) B, has a large influence on the wear resistance. The term
"the atomic ratio of Al to the total of Ti, Cr, Al and Si in the
layer(s) A and the layer(s) B" is hereinafter sometimes referred to
as "the total Al atomic ratio". As a result of further studies made
by the present inventors, it has been found that it is preferred
that the above total Al atomic ratio falls within a range of 0.20
to 0.60, in order to ensure the more excellent wear resistance. As
the lower limit of the above total Al atomic ratio, it is more
preferably 0.30 or more, still more preferably 0.35 or more, and
yet still more preferably 0.40 or more. Also, as the upper limit of
the above total Al atomic ratio, it is more preferably 0.55 or
less.
[0036] The above total Al atomic ratio can be calculated in the
following manner. The laminated hard film of the present invention
is described, taking a combination of the following layer A1 and
layer B1 as an example.
[0037] Composition of Layer A1: (Cr.sub.1-cAl.sub.c)N, thickness of
layer A1 : q nm, that is, a=0, d=0, b=1-c and x=0 in the specified
composition
[0038] Composition of Layer B1: CrN, thickness of layer B1: r mm,
that is, e=1 and y=0 in the specified composition
[0039] In this case, the layer A1 and the layer B1 have the same
crystal structure. The lattice constant of the layer A1 can be
determined as .alpha.=0.412/0.02.times.c nm, and the lattice
constant of the layer B1 can be determined as .beta.=0.414 nm. The
respective atomic numbers of Al and Cr contained in respective unit
volumes of the layer A1 and the layer B1 are determined from the
following formulas. The following formulas are determined from the
crystal structure.
Al Atomic Number in Layer A1=(1/.alpha.).sup.3.times.4.times.c
Cr Atomic Number in Layer
A1=(1/.alpha.).sup.3.times.4.times.(1-c)
Cr Atomic Number in Layer B1=(1.alpha.).sup.3.times.4
[0040] Then, the atomic ratio of A1 to the total of Cr and Al in
the above layer A1 and layer B1 can be determined by multiplying
each atomic number by the thickness of each layer, as shown
below.
Atomic Ratio of A1 to Total of Cr and Al in Layer A1 and Layer
B1=(1/.alpha.).sup.3.times.4.times.c.times.q/[(1/.alpha.).sup.3.times.4.t-
imes.(1-c).times.q+(1/.beta.).sup.3.times.4.times.r]
[0041] In the above example, the combination of CrAlN as the layer
A and CrN as the layer B is used. However, even in any combination
of the layer A and the layer B specified in the present invention,
the total A1 atomic ratio can be determined by performing
calculation as described above. When the crystal structure is
unknown, the calculation as described above cannot be performed.
Therefore, the formed layer A or layer B is subjected to
measurement by EDX, and the total Al atomic ratio may be determined
using the measured results.
[0042] In the above layer(s) A, it is also effective that Ti in the
layer(s) A is at least partially substituted with Zr, thereby
further improving the wear resistance of the layer(s) A. Such an
effect is increased as the amount of Zr to be substituted
increases. This is because the film components are oxidized by heat
generation during sliding in the case of use as a molding die to
foul! a hard oxide film containing Zr on a surface thereof.
[0043] Although the ratio of Ti to be substituted with Zr is not
particularly limited, it is preferably at least 10% or more to the
Ti amount. All of the Ti amount may be substituted with Zr. The
preferred atomic ratio range of Zr in this case is the same as the
range of the above a in the case where Zr is not allowed to be
contained and only Ti is allowed to be contained. That is, when Zr
is allowed to be contained in place of Ti, the atomic ratio of Zr
is preferably 0.01 or more, and more preferably 0.02 or more, to
the whole metal elements of the layer(s) A. However, when the Zr
amount is excessive, the oxidation resistance of the layer(s) A is
decreased, particularly during hot forming. Therefore, the atomic
ratio of Zr is preferably 0.10 or less, more preferably 0.08 or
less, and still more preferably 0.05 or less.
[0044] The molding die further excellent in the wear resistance and
the toughness can be realized by providing the laminated hard film
as described above on/above the substrate surface. Further, the
molding die of the present invention exerts the excellent
properties, particularly also at high temperature, and therefore,
is particularly useful as a die to be used for hot forming of a
steel material.
[0045] The molding die of the present invention may include a CrN
layer having a thickness of 3 to 10 .mu.m as an intermediate layer
between the above laminated hard film and the substrate, namely
just on the substrate. This allows the excellent wear resistance
and toughness to be exerted, while ensuring good adhesion between
the laminated hard film and the substrate surface. The thickness of
the intermediate layer in this case is preferably 3 .mu.m or more,
from the viewpoint of ensuring the adhesion. On the other hand,
when the intermediate layer is excessively thick, the toughness of
the whole film is deteriorated. Therefore, it is preferably 10
.mu.m or less. More preferably, it is from 5 to 8 .mu.m.
[0046] Although the kind of the substrate used in the above molding
die is not particularly limited, examples thereof include
tungsten-carbide-based cemented carbides such as WC--Co--based
alloys, WC--TiC--Co--based alloys, WC--TiC--(TaC or NbC)--Co--based
alloys and WC--(TaC or NbC)--Co--based alloys; cermet alloys such
as TiC--Ni--Mo--based alloys and TiC--TiN--Ni--Mo--based alloys;
high-speed tool steel materials such as SKH51 and SKD61 specified
in JIS G 4403 (2006); alloy tool steel materials such as SKS11 and
SKD1 specified in JIS G 4404 (2006); and the like.
[0047] The hard film is formed on/above the substrate surface by
using conventional methods such as a physical vapor deposition
process (PVD process) and a chemical vapor deposition process (CVD
process). Among these processes, the PVD process is preferably used
to form the film, from the viewpoint of the adhesion of the hard
film and the like. Specifically, there is a process of evaporating
or ionizing a target used as a solid evaporation source and forming
the film on/above the substrate in a gas atmosphere containing
nitrogen or hydrocarbon.
[0048] As such a process, for example, an ion plating process such
as an arc ion plating (ATP) process or a reactive PVD process such
as a sputtering process is effective. Further, when the sputtering
process is applied, unbalanced magnet sputtering (UBMS) having a
large amount of ion irradiation to the substrate of the film to be
formed is preferred.
[0049] Even when any of the film forming processes is adopted, the
component composition of the target is preferably the same as the
desired film composition, because the component composition of the
target to be used determines the component composition of the film
to be formed.
[0050] When the film is formed by the arc ion plating process, as
the preferred conditions, examples thereof include, for example,
the following conditions. When an iron-based material such as the
tool steel material is used as the substrate, the substrate
temperature during deposition is preferably 500.degree. C. or
lower.
[0051] Total Pressure: 0.5 Pa or more and 4 Pa or less
[0052] Applied Current (Discharge Current): 100 to 200 A
[0053] Substrate Temperature during Film Formation: 300.degree. C.
or higher and 800.degree. C. or lower.
[0054] The laminated hard film of the present invention is suitable
for use in a molding die because of its excellent wear resistance
and toughness. However, it can also be used, for example, as a hard
film formed on/above a surface of a cutting tool by taking
advantage of its properties.
EXAMPLES
[0055] The present invention is described more specifically below
with reference to examples. However, it should be construed that
the present invention is in no way limited by the following
examples, and appropriate changes may be made without departing
from the spirit and scope of the present invention described above
and later. All of those are also included in the technical scope of
the present invention.
Example 1
[0056] Monolayer or laminated films having compositions shown in
the following Table 1 were formed by an ATP system. At this time,
targets corresponding to respective metal parts of layers A and
layers B were used as targets. In addition, a fine particle
WC--Co--based cemented carbide ball with a diameter of 10 mm, which
had the same composition as a fine particle cemented carbide HTi10
manufactured by Mitsubishi Materials Corporation was used, after a
surface thereof was mirror-finished. As for test Nos. 1 to 31 in
the following Table 1, CrN films having a thickness of 5 .mu.m were
formed as intermediate layers prior to the formation of the films.
Further, as for test No. 32, the film was directly formed on a
substrate surface without forming an intermediate layer.
TABLE-US-00001 TABLE 1 Number of Layer A Layer B Times Compo-
Compo- of sition Thick- sition Thick- lami- Test (Atomic ness
(Atomic ness nating No. Ratio) (nm) Ratio) (nm) (times) 1 TiN 5000
-- -- -- 7 CrN 5000 -- -- -- 3 (Ti.sub.0.5Al.sub.0.5)N 5000 -- --
-- 4 (Al.sub.0.5Cr.sub.0.5)N 5000 -- -- -- 5
(Al.sub.0.5Cr.sub.0.5)N 1 CrN 1 2500 6 (Al.sub.0.5Cr.sub.0.5)N 3
CrN 3 833 7 (Al.sub.0.5Cr.sub.0.5)N 10 CrN 10 250 8
(Al.sub.0.5Cr.sub.0.5)N 15 CrN 15 125 9 (Al.sub.0.5Cr.sub.0.5)N 30
CrN 30 83 10 (Al.sub.0.5Cr.sub.0.5)N 50 CrN 50 50 11
(Al.sub.0.5Cr.sub.0.5)N 100 CrN 100 25 12 (Al.sub.0.5Cr.sub.0.5)N
300 CrN 300 8 13 (Al.sub.0.3Cr.sub.0.7)N 10 CrN 10 250 14
(Al.sub.0.7Cr.sub.0.3)N 10 CrN 10 250 15 (Al.sub.0.9Cr.sub.0.1)N 10
CrN 10 250 16 (Al.sub.0.5Cr.sub.0.5)(C.sub.0.1N.sub.0.9) 10
Cr(C.sub.0.1N.sub.0.9) 10 250 17 AlN 10 CrN 10 250 18
(Al.sub.0.5Cr.sub.0.45Si.sub.0.05)N 10 CrN 10 250 19
(Al.sub.0.45Cr.sub.0.45Si.sub.0.1)N 10 CrN 10 750 20
(Ti.sub.0.05Al.sub.0.5Cr.sub.0.45)N 10 CrN 10 250 21
(Ti.sub.0.2Al.sub.0.4Cr.sub.0.4)N 10 CrN 10 250 22
(Ti.sub.0.03Al.sub.0.52Cr.sub.0.4 10 CrN 10 250 Si.sub.0.05)N 23
(Ti.sub.0.03Al.sub.0.52Cr.sub.0.4 10 (Cr.sub.0.95Si.sub.0.05)N 10
250 Si.sub.0.05)N 24 (Ti.sub.0.03Al.sub.0.52Cr.sub.0.4 10
(Al.sub.0.95Si.sub.0.05)N 10 250 Si.sub.0.05)N 25
(Al.sub.0.5Cr.sub.0.5)N 10 (Cr.sub.0.95Si.sub.0.05)N 10 250 26
(Al.sub.0.5Cr.sub.0.5)N 10 (Cr.sub.0.8Si.sub.0.2)N 10 250 27
(Ti.sub.0.03Zr.sub.0.02Al.sub.0.5 10 CrN 10 250 Cr.sub.0.45)N 28
(Zr.sub.0.05Al.sub.0.5Cr.sub.0.45)N 10 CrN 10 750 29
(Al.sub.0.5Cr.sub.0.5)N 10 AIN 10 250 30 (Al.sub.0.5Cr.sub.0.5)N 10
(Al.sub.0.95Si.sub.0.05)N 10 250 31 (Al.sub.0.5Cr.sub.0.5)N 10
(Al.sub.0.85Si.sub.0.15)N 10 250 32 (Al.sub.0.5Cr.sub.0.5)N 10 CrN
10 250
[0057] Specifically, the substrate as a body to be treated was
heated to a temperature of 400.degree. C. by a heater mounted in a
chamber of the above ATP system, and cleaning of the substrate
surface by Ar ion was performed. The cleaning conditions were
atmosphere: Ar, pressure: 0.6 Pa, voltage: 500 V and time: 5
min
[0058] Thereafter, in a nitrogen atmosphere or an atmosphere of
nitrogen+methane in the case of a C-containing film, the pressure
in the chamber was adjusted to 4 Pa, and an arc discharge was
started at a discharge current of 150 A to form a film having a
total thickness of about 5 .mu.m (about 5,000 nm) on the substrate.
During the deposition, a bias voltage of 50 V was applied to the
substrate so that the substrate has a minus potential to an earth
potential.
[0059] When laminated hard films were formed as shown in test Nos.
5 to 32 in the above Table 1, the targets having compositions of
the layers A and the layers B were attached to separate evaporation
sources, respectively, and a table on which the substrate was
mounted was rotated in the AlP system. First, only the target of
the layers A was independently discharged in the nitrogen
atmosphere or the nitrogen-methane atmosphere for a short period of
time to form the layer A on a surface of the above intermediate
layer or the substrate surface. Then, the target of the layers B
was discharged, and thereafter, the table was rotated while
concurrently discharging the layers A and the layers B, thereby
forming a multilayer film.
[0060] In the above example, after the layer A was formed on the
surface of the intermediate layer or the substrate surface, the
layer B was formed. However, whichever of the layer A and the layer
B may be present on the substrate side, there is slight difference
in the properties therebetween.
[0061] The thickness of the layer A, the thickness of the layer B
and the number of times of laminating in the multilayer film were
adjusted by varying the rotation speed of the table. That is, when
the rotation speed is increased, the thickness of the layer A and
the thickness of the layer B are decreased, and the number of times
of laminating is increased. When the rotation speed is decreased,
the thickness of the layer A and the thickness of the layer B are
increased, and the number of times of laminating is decreased. As
shown in test Nos. 1 to 4 in Table 1 as comparative examples,
various monolayer films were also formed in accordance with
ordinary procedures.
[0062] As for the resulting cemented carbide balls coated with
various films, a sliding test was performed under the following
conditions to evaluate the wear resistance of the films. At this
time, an alumina plate was used as the following plate in place of
a steel plate having scales. The diameter of a worn pan of the ball
was measured, and the area corresponding to the diameter was
evaluated as the wear amount. The case where the wear amount was
0.4 .mu.m.sup.2 or less was evaluated as excellent in the wear
resistance.
Sliding Test Conditions
[0063] Test Method: ball-on-plate type reciprocating sliding
[0064] Ball: cemented carbide balls coated with various films
[0065] Plate: an alumina plate
[0066] Vertical Load: 5N
[0067] Sliding Speed: 0.1 m/sec
[0068] Sliding Amplitude: 30 mm
[0069] Sliding Distance: 72 m
[0070] Temperature: room temperature
[0071] Also, as for respective hard film coating members, a scratch
test was performed under the following conditions to evaluate the
toughness of the films. At this time, the critical load at which
chipping occurred in the film was measured, while increasing the
pressing load of an indenter from a load of 0 N to a load of 100 N
at the following load increase rate. The case where the critical
load measured value was 70 N or more was evaluated as excellent in
the toughness.
Scratch Test Conditions
[0072] Indenter: a diamond indenter whose tip has a radius of
curvature of 200 .mu.m
[0073] Load Increase Rate: 100 N/min
[0074] Maximum Load: 100 N
[0075] Indenter Moving Speed: 10 mm/min
[0076] Temperature: room temperature
[0077] These evaluation results are shown in the following Table
2.
TABLE-US-00002 TABLE 2 Test Scratch Critical Wear Amount No. Load
(N) (.mu.m.sup.2) 1 60 1.00 2 100 0.70 3 60 1.00 4 60 0.60 5 80
0.60 6 80 0.30 7 100 0.10 8 100 0.12 9 100 0.15 10 100 0.15 11 70
0.40 12 70 0.70 13 80 0.60 14 100 0.07 15 80 0.10 16 90 0.15 17 50
0.30 18 80 0.08 19 80 0.60 20 100 0.08 71 100 0.70 22 100 0.08 93
100 0.06 74 100 0.09 25 100 0.06 26 70 0.60 27 80 0.08 28 100 0.05
29 100 0.12 30 100 0.08 31 70 0.70 32 90 0.10
[0078] From these results, consideration can be made as follows. In
test Nos. 6 to 11, 14 to 16, 18, 20, 22 to 25, 27 to 30 and 32, the
compositions of the layers A and the layers B satisfy the range
specified in the present invention. Therefore, it is found that
good wear resistance and toughness are exerted.
[0079] In contrast, test Nos. Ito 5, 12, 13, 17, 19, 21, 26 and 31
do not satisfy any one of the requirements specified in the present
invention, and at least either of the wear resistance and the
toughness is deteriorated. That is, test No. I is a conventional
TiN monolayer film, and both the wear resistance and the toughness
are deteriorated. Test No. 2 is a conventional CrN monolayer film,
and the wear resistance is deteriorated.
[0080] Test Nos. 3 and 4 are examples of forming a monolayer type
film formed of only the layer A, and both the wear resistance and
the toughness are deteriorated. Test No. 5 is an example in which
the layer A and the layer B are thin in thickness, and the wear
resistance is deteriorated.
[0081] Test No. 12 is an example in which the layer A and the layer
B are thick in thickness, and the wear resistance is deteriorated.
Test No. 13 is an example in which the Al amount in the layers A is
insufficient, and the wear resistance is deteriorated. Test No. 17
is an example in which the Al amount in the layers A is excessive,
and the toughness is deteriorated. Test No. 19 is an example in
which the Al amount in the layers A is insufficient and the Si
amount is excessive, and the wear resistance is deteriorated.
[0082] Test No. 21 is an example in which the Ti amount in the
layers A is excessive and the Al amount is insufficient, and the
wear resistance is deteriorated. Test No. 26 is an example in which
the Cr amount in the layers B is small and the Si amount is
excessive, and the wear resistance is deteriorated. Test No. 31 is
an example in which the Al amount in the layers B is small and the
Si amount is excessive, and the wear resistance is
deteriorated.
[0083] In this example, the sliding test and the scratch test were
performed at room temperature to evaluate the wear resistance and
the toughness of the films. However, it is considered that even
when the temperature is increased, for example, to such a high
temperature as about 400 to 500.degree. C., the results are hardly
influenced thereby. Therefore, the film of the present invention is
excellent also in the properties at the above high temperature.
Example 2
[0084] Laminated films having compositions shown in the following
Table 3 were formed in the same manner as in Example 1. In all
examples of the following Table 3, CrN films having a thickness of
5 .sub.lam were formed as intermediate layers prior to the
formation of the films. The film of No. 7 in Table 3 is the same as
the film of No. 22 in Table 1. Further, the film of No. 10 in Table
3 is the same as the film of No. 27 in Table 1, the film of No. 12
in Table 3 is the same as the film of No. 28 in Table 1, the film
of No. 14 in Table 3 is the same as the film of No. 25 in Table 1,
and the film of No, 16 in Table 3 is the same as the film of No. 30
in Table 1.
[0085] The total Al atomic ratios of the resulting various films
were determined from the compositions of the respective layers,
lattice constants shown in Table 3 and thicknesses of the
respective layers by the method described above. The total Al
atomic ratios are shown in Table 3. In addition, as for the
resulting cemented carbide balls coated with various films, the
sliding test was performed in the same manner as in Example 1 to
evaluate the wear resistance of the films. Furthermore, as for
respective hard film coating members, the scratch test was
performed in the same manner as in Example 1 to evaluate the
toughness of the films. These results are shown in Table 4.
TABLE-US-00003 TABLE 3 Number of Layer A Layer B Times Layer Compo-
Lattice Layer Total of Lattice Thick- sition Con- Thick- Al Lami-
Test Composition Constant ness (Atomic stant ness Atomic nating No.
(Atomic Ratio) (nm) (nm) Ratio) (nm) (nm) Ratio (times) 1
(Al.sub.0.7Cr.sub.0.3)N 0.4126 70 CrN 0.414 5 0.56 200 2
(Al.sub.0.7Cr.sub.0.3)N 0.4126 20 CrN 0.414 10 0.47 167 3
(Al.sub.0.7Cr.sub.0.3)N 0.4126 20 CrN 0.414 20 0.35 125 4
(Al.sub.0.7Cr.sub.0.3)N 0.4126 20 CrN 0.414 40 0.23 83 5
(Al.sub.0.5Cr.sub.0.5)N 0.413 20 CrN 0.414 10 0.33 167 6
(Al.sub.0.5Cr.sub.0.5)N 0.413 10 CrN 0.414 5 0.33 333 7
(Ti.sub.0.03Al.sub.0.52Cr.sub.0.40 0.43386 10 CrN 0.414 10 0.24 250
Si.sub.0.05)N 8 (Ti.sub.0.03Al.sub.0.52Cr.sub.0.40 0.43386 10 CrN
0.414 5 0.33 333 Si.sub.0.05)N 9 (Ti.sub.0.03Al.sub.0.52Cr.sub.0.40
0.43386 20 CrN 0.414 5 0.40 200 Si.sub.0.05)N 10
(Ti.sub.0.03Zr.sub.0.02Al.sub.0.5 0.41416 10 CrN 0.414 10 0.25 250
Cr.sub.0.45)N 11 (Ti.sub.0.03Zr.sub.0.02Al.sub.0.5 0.41416 20 CrN
0.414 10 0.33 167 Cr.sub.0.45)N 12
(Zr.sub.0.05Al.sub.0.5Cr.sub.0.45)N 0.41515 10 CrN 0.414 10 0.25
250 13 (Zr.sub.0.05Al.sub.0.5Cr.sub.0.45)N 0.41515 20 CrN 0.414 5
0.40 200 14 (Al.sub.0.5Cr.sub.0.5)N 0.413 10
(Cr.sub.0.95Si.sub.0.05)N 0.414 10 0.25 250 15
(Al.sub.0.5Cr.sub.0.5)N 0.413 20 (Cr.sub.0.9Si.sub.0.1N 0.414 10
0.33 167 16 (Al.sub.0.5Cr.sub.0.5)N 0.413 10
(Al.sub.0.95Si.sub.0.05)N 0.412 10 0.25 250 17
(Al.sub.0.5Cr.sub.0.5)N 0.413 10 (Al.sub.0.95Si.sub.0.05)N 0.412 5
0.33 333
TABLE-US-00004 TABLE 4 Test Scratch Critical Wear Amount No. Load
(N) (.mu.m.sup.2) 1 90 0.15 2 100 0.05 3 100 0.04 4 80 0.2 5 90
0.05 6 90 0.05 7 100 0.08 8 100 0.05 9 100 0.04 10 80 0.12 11 80
0.06 12 100 0.13 13 100 0.05 14 100 0.14 15 100 0.04 16 100 0.08 17
100 0.05
[0086] From the results of Table 3 and Table 4, consideration can
be made as follows. As for all of Nos. 1 to 17 in Table 3, the
ratios of the elements in each layer of the layers A and the layers
B are within the specified ranges, and the total Al atomic ratio is
within the preferred range. As a result, it is found that good wear
resistance and toughness are exerted. The total Al atomic ratio is
within the preferred range as described above, so that it is found
that the wear amount is 0.20 .mu.m.sup.2 or less, which shows good
toughness. In particular, it is found that in the examples in which
the total Al atomic ratio is within the range of 0.35 to 0.55, a
wear amount of 0.10 .mu.m.sup.2 or less can be achieved to show
sufficiently excellent toughness.
[0087] Although the present invention has been described in detail
with reference to the specific embodiments, it will be apparent to
those skilled in the art that various variations and modifications
can be made without departing from the spirit and scope of the
present invention.
[0088] The present application is based on Japanese Patent
Application No. 2014-193885 filed on Sep. 24, 2014 and Japanese
Patent Application No. 2014-266487 filed on Dec. 26, 2014, the
contents of which are incorporated herein by reference.
INDUSTRIAL APPLICABILITY
[0089] A laminated hard film of the present invention is more
enhanced in wear resistance and toughness, and is useful for a
.sub.jig and tool or a molding die having an cemented carbide, a
cermet, a high-speed tool steel, an alloy tool steel or the like as
a substrate.
* * * * *