U.S. patent application number 12/087066 was filed with the patent office on 2009-01-01 for titanium alloy for corrosion-resistant materials.
Invention is credited to Takashi Maeda, Satoshi Matsumoto, Keisuke Nagashima.
Application Number | 20090004042 12/087066 |
Document ID | / |
Family ID | 36800130 |
Filed Date | 2009-01-01 |
United States Patent
Application |
20090004042 |
Kind Code |
A1 |
Matsumoto; Satoshi ; et
al. |
January 1, 2009 |
Titanium Alloy for Corrosion-Resistant Materials
Abstract
An object is to provide a titanium alloy for corrosion-resistant
materials that is capable of being produced at low cost while
maintaining the capability to suppress the deterioration of
corrosion resistance. According to the present invention, there is
provided a titanium alloy for corrosion-resistant materials, which
contains 0.01-0.12% by mass in total of at least one of platinum
group elements, at least one of Al, Cr, Zr, Nb, Si, Sn and Mn, and
the residue comprising Ti and impurities, in which the total
content of Al, Cr, Zr, Nb, Si, Sn and Mn is 5% by mass or less.
Inventors: |
Matsumoto; Satoshi; (Osaka,
JP) ; Nagashima; Keisuke; (Osaka, JP) ; Maeda;
Takashi; (Osaka, JP) |
Correspondence
Address: |
CLARK & BRODY
1090 VERMONT AVENUE, NW, SUITE 250
WASHINGTON
DC
20005
US
|
Family ID: |
36800130 |
Appl. No.: |
12/087066 |
Filed: |
July 31, 2006 |
PCT Filed: |
July 31, 2006 |
PCT NO: |
PCT/JP2006/315132 |
371 Date: |
June 25, 2008 |
Current U.S.
Class: |
420/418 ;
420/417; 420/421 |
Current CPC
Class: |
C22C 14/00 20130101;
C22F 1/183 20130101 |
Class at
Publication: |
420/418 ;
420/417; 420/421 |
International
Class: |
C22C 14/00 20060101
C22C014/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 28, 2005 |
JP |
2005-377163 |
Claims
1. A titanium alloy for corrosion-resistant materials, containing
0.01-0.12% by mass in total of at least one of platinum group
elements, at least one of Al, Cr, Zr, Nb, Si, Sn and Mn, and the
residue comprising Ti and impurities, wherein the total content of
Al, Cr, Zr, Nb, Si, Sn and Mn is 5% by mass or less.
2. A titanium alloy for corrosion-resistant materials, containing
0.01-0.12% by mass in total of at least one of platinum group
elements, 0.05-2.00% by mass in total of any one or both of Co and
Ni, at least one of Al, Cr, Zr, Nb, Si, Sn and Mn, and the residue
comprising Ti and impurities, where in the total content of Al, Cr,
Zr, Nb, Si, Sn and Mn is 5% by mass or less.
3. canceled
4. canceled
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a titanium alloy for
corrosion-resistant materials.
BACKGROUND OF THE INVENTION
[0002] Titanium forms thereon an oxidized film and therefore is not
easily corroded as compared with general metals, so that it is
widely used in a place requiring corrosion resistance. However, in
this intended use, there is a demand for titanium having more
excellent corrosion resistance, and in order to deal with it,
corrosion resistance is improved hitherto by adding another element
to titanium.
[0003] For example, as titanium having improved corrosion
resistance, Ti--Pd alloys, which are also prescribed in JIS 11
type, 12 type and 13type, are known. These are alloys containing
0.12-0.25% by mass of Pd in pure titanium. Also, it is conventional
to contain therein Co, Ni or the like other than Pd (cf. Patent
Documents 1 and 2).
[0004] Meanwhile, titanium has excellent characteristics as
compared with general metals, and specifically it has not only
excellent corrosion resistance but also a light weight and a high
strength, and therefore various alloys are used in various
applications, such as sports goods such as golf clubs and bicycles.
However, titanium alloys are expensive compared with general
metals, and in these days, utilization of low cost, recycled
titanium alloys, which are obtained by recycling not only sponge
titanium produced from titanium ores, but also titanium alloys,
which were once introduced into markets and had become out of use,
are now being studied.
[0005] However, when even a small amount of another element is
mixed in titanium for which corrosion resistance is required as
mentioned above, corrosion may occur starting at such an element,
and therefore recycled titanium alloys are not used for titanium
alloys for corrosion-resistant materials. Furthermore, platinum
group elements, such as Pd, are generally expensive compared with
titanium and therefore titanium alloys for corrosion-resistant
materials have been very expensive in the past.
[0006] In other words, conventional titanium alloys for
corrosion-resistant materials have a problem in that they cannot be
produced at low cost while maintaining the capability to suppress
the deterioration of corrosion resistance.
[0007] Patent Document 1: Japanese Patent No. 2132925
[0008] Patent Document 2: Japanese Patent Application Publication
No. Hei-4-57735
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0009] In consideration of the above problems, it is an object of
the present invention to provide a titanium alloy for
corrosion-resistant materials that is capable of being produced at
low cost while maintaining the capability to suppress the
deterioration of corrosion resistance.
[0010] The present inventors intensively studied in order to solve
the above problems, consequently found that it is possible to
suppress the deterioration of corrosion resistance when a certain
amount or less of at least one of Al, Cr, Zr, Nb, Si, Sn and Mn is
contained in a titanium alloy, and thus achieved the present
invention.
[0011] Specifically, according to the present invention, there is
provided a titanium alloy for corrosion-resistant materials, which
is characterized in that it contains 0.01-0.12% by mass in total of
at least one of platinum group elements, at least one of Al, Cr,
Zr, Nb, Si, Sn and Mn, in which at least one of Sn and Mn is
included, and the residue comprising Ti and impurities, in which
the total content of Al, Cr, Zr, Nb, Si, Sn and Mn is 5% by mass or
less.
[0012] By containing Al, Cr, Zr, Nb, Si, Sn and Mn in a titanium
alloy is meant that Al, Cr, Zr, Nb, Si, Sn and Mn each are present
in the titanium alloy in an amount exceeding the unavoidable level.
The content of each of these elements can be measured by using a
conventionally used analytic instrument. Usually, the contents, as
the unavoidable levels, of these elements present in a titanium
alloy are, at maximum, Al: 0.007% by mass, Cr: 0.007% by mass, Zr:
0.001% by mass, Nb: 0.001% by mass, Si: 0.004% by mass, Sn: 0.001%
by mass and Mn: 0.001% by mass, respectively. Accordingly, by
containing Al, Cr, Zr, Nb, Si, Sn and Mn in a titanium alloy is
meant in the specification of this application that these elements
each are present in the titanium alloy in an amount exceeding the
corresponding amount.
Advantages of the Invention
[0013] According to the present invention, Al, Cr, Zr, Nb, Si, Sn
or Mn is contained in a titanium alloy for corrosion-resistant
materials, so that it is possible to reuse recycled titanium alloys
coming from products in which at least one of Al, Cr, Zr, Nb, Si,
Sn and Mn is used. In addition, according to the present invention,
0.01-0.12% by mass in total of at least one of platinum group
elements is contained in the titanium alloy for corrosion-resistant
materials, and the total content of Al, Cr, Zr, Nb, Si, Sn and Mn
is 5% by mass or less. Whereby, it is possible to suppress the
deterioration of corrosion resistance.
[0014] In other words, it is possible to provide a titanium alloy
for corrosion-resistant materials that is capable of being produced
at low cost while maintaining the capability to suppress the
deterioration of corrosion resistance.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0015] Now, the description will be made for a preferred embodiment
of a titanium alloy for corrosion-resistant materials. First, the
description will be made for the amount of each element contained
in a titanium alloy for corrosion-resistant materials and the
reason for determining the amount thereof.
[0016] A titanium alloy for corrosion-resistant materials of this
embodiment usually contains a platinum group element, any one or
both of Co and Ni, at least one of Al, Cr, Zr, Nb, Si, Sn and Mn,
in which at least one of Sn and Mn is included, and the residue
comprising Ti and impurities.
[0017] The platinum group element is an essential component of a
titanium alloy for corrosion-resistant materials, and the content
thereof is 0.01-0.12% by mass. The content of the platinum group
element is 0.01-0.12% for the reason that when the platinum group
element is less than 0.01% by mass, the corrosion resistance of the
titanium alloy for corrosion-resistant materials does not reach a
satisfactory level, which may cause corrosion, and on the other
hand, even when the content thereof exceeds 0.12% by mass, it
cannot be expected to have the corrosion resistance improved as the
increase of the content thereof, and in addition, there is a
possibility of increasing the cost of a titanium alloy for
corrosion-resistant materials.
[0018] As this platinum group element, it is possible to use Ru,
Rh, Pd, Os, Ir and Pt, and preferably use Pd.
[0019] Co and Ni are optional components, and the content thereof
is 0.05-2.00% by mass. These may be contained in the titanium alloy
for corrosion-resistant materials, in place of Ti contained in the
titanium alloy as a residue of the essential components, such as
the platinum group element and at least one of hereinafter
described Al, Cr, Zr, Nb, Si, Sn and Mn. They are contained in the
amount of 0.05-2.00% by mass, thereby producing an advantage of
further improving the corrosion resistance while increasing the
strength of the titanium alloy for corrosion-resistant materials.
When the total amount of Co and Ni is less than 0.05% by mass, it
is difficult to produce the advantage of further improving the
corrosion resistance while increasing the strength of the titanium
alloy.
[0020] The at least one of Al, Cr, Zr, Nb, Si, Sn and Mn, in which
at least one of Sn and Mn is included, is an essential component of
a titanium alloy for corrosion-resistant materials, and the total
content of Al, Cr, Zr, Nb, Si, Sn and Mn is 5% by mass or less.
These elements are contained in such a range for the reason that
when the total content of Al, Cr, Zr, Nb, Si, Sn and Mn exceeds 5%,
the corrosion resistance of the titanium alloy for
corrosion-resistant materials is deteriorated, which causes
corrosion. From these points of view, the total content of them is
preferably 3% or less, and more preferably 2% or less.
[0021] Examples of impurities include unavoidable impurities such
as C, O, H and Fe, and a small amount of another element may be
contained in the titanium alloy for corrosion-resistant materials
to such an extent as not to deteriorate the advantages of the
present invention. Especially, V, Mo and W are known as the
elements causing less influences on the corrosion resistance, and
can be contained in a titanium alloy for corrosion-resistant
materials as long as the total content thereof is about 5% by mass
or less.
[0022] The titanium alloy for corrosion-resistant materials
mentioned above is preferably used for conduits, heat exchangers,
electrolysis vessels and the like of such as a nickel refining
plant, which are used in environments, in which they are exposed to
concentrated sulfuric acid, nickel sulfate or nickel chloride at
about 250.degree. C.
EXAMPLES
[0023] Now, the description will be made for the present invention
in more detail with reference to examples without intention to
limit the present invention thereto.
[0024] (Preparation of samples)
Examples 1 to 8, Comparative Examples 1 to 11, and Reference
Examples 1-21
[0025] Titanium alloys for corrosion-resistant materials are
prepared by adjusting samples for evaluation on corrosion
resistance of the respective Examples, Comparative Examples and
Reference Examples, using pure titanium and the respective
components so as to have the components of Tables 1 and 2 contained
in the amounts of Tables 1 and 2. For Comparative Example 1, pure
titanium is used.
[0026] First, the titanium alloy of each composition is produced
with a size having a thickness of 20 mm, a width of 70 mm and a
length of 90 mm by melting through button arc melting.
[0027] Then, the thus produced pieces each are hot rolled into 3 mm
thickness, and then acid-washed, thereby removing scale from the
surface, and cut into a test piece having a width of 50 mm and a
length of 100 mm. Then, one side of this test piece is polished
with a #200 polishing sheet, while the lateral and rear sides
thereof were sealed with a sealing agent, thereby allowing only the
polished surface to be exposed to the surface. Thus, each sample
for evaluation of corrosion resistance is prepared.
[0028] As a conventional titanium alloy for corrosion-resistant
materials produced from sponge titanium or the like, a titanium
alloy for corrosion resistance (Conventional Examples 1-4)
containing the components shown in Table 3 are prepared and
evaluated in the same manner as in Examples and Comparative
Examples.
TABLE-US-00001 TABLE 1 Components (%) * Total Pd Co Ni Mn Sn Al Cr
Zr Nb Si ** Example 1 0.05 3 3 Example 2 0.05 0.35 4 4 Example 3
0.05 3 3 Reference 0.02 3 3 Example 1 Reference 0.1 3 3 Example 2
Example 4 0.05 0.35 1 1 2 Example 5 0.05 0.1 0.15 3 3 Reference
0.05 0.01 0.01 0.02 Example 3 Reference 0.05 0.35 0.01 0.01 0.02
Example 4 Reference 0.05 0.35 0.01 0.01 0.02 Example 5 Example 6
0.05 0.2 0.15 0.01 0.01 0.02 Reference 0.05 4 4 Example 6 Reference
0.05 3.5 3.5 Example 7 Reference 0.05 0.1 0.15 3 3 Example 8
Reference 0.05 2 2 4 Example 9 Reference 0.05 2 2 Example 10
Reference 0.05 0.1 0.2 0.2 0.5 Example 11 Reference 0.05 1 1
Example 12 Example 7 0.05 1 1 Reference 0.05 0.5 0.5 1 Example 13
Example 8 0.05 1 1 2 Reference 0.05 1 1 2 Example 14 Reference 0.05
0.1 0.1 Example 15 Reference 0.05 0.1 0.1 Example 16 Reference 0.05
0.4 0.4 Example 17 Reference 0.05 1 1 Example 18 Reference 0.05 1 1
Example 19 Reference 0.05 1.5 1.5 Example 20 Reference 0.05 1 0.6
1.6 Example 21 * The numerals in Table are given in percent by
mass. ** The total content of Mn, Sn, Al, Cr, Zr, Nb and Si is
represented.
TABLE-US-00002 TABLE 2 Components (%) * Total Pd Co Ni Mn Sn Al Cr
Zr Nb Si ** Comparative -- 0 Example 1 Comparative 0.05 6 6 Example
2 Comparative 0.05 0.35 6 6 Example 3 Comparative 0.05 6 6 Example
4 Comparative 0.05 3 3 6 Example 5 Comparative 0.05 0.1 0.2 6 6
Example 6 Comparative 0.05 6 7 13 Example 7 Comparative 0.05 2 5 7
Example 8 Comparative 0.05 6 6 Example 9 Comparative 0.05 5.5 5.5
Example 10 Comparative 0.05 6 6 Example 11 * The numerals in Table
are given in percent by mass. ** The total content of Mn, Sn, Al,
Cr, Zr, Nb and Si is represented.
TABLE-US-00003 TABLE 3 Components (%) * Total Pd Co Ni Mn Sn Al Cr
Zr Nb Si ** Conven- 0.05 0 tional Example 1 Conven- 0.05 0.35 0
tional Example 2 Conven- 0.05 0.35 0 tional Example 3 Conven- 0.02
0.2 0.15 0 tional Example 4 * The numerals in Table are given in
percent by mass. ** The total content of Mn, Sn, Al, Cr, Zr, Nb and
Si is represented.
[0029] (Nickel-chloride-resistance test)
[0030] The samples of Examples, Comparative Examples, Reference
Examples and Conventional Examples for evaluation on corrosion
resistance each are immersed in 20% nickel chloride solution at
100.degree. C. for 100 hours, and the surface of each of the
samples are observed by eyes and an optical microscope. Thus, the
surface texture is evaluated. According to the result of the
evaluation, it is determined as ".largecircle." for a sample in
which no change is confirmed between its initial surface condition
and its surface condition after the immersion in the nickel
chloride solution, as ".smallcircle." for a sample in which
increase of unevenness or the like is slightly confirmed
therebetween, and as ".DELTA." for a sample in which increase of
unevenness or the like is apparently confirmed therebetween. The
results are shown in Table 4.
[0031] The weight of each sample for evaluation of corrosion
resistance is measured before and after the immersion in the nickel
chloride solution by using an electronic balance that is capable of
measuring the weight with the unit of 0.1 mg, and the difference
thereof is calculated as a weight reduction (.DELTA.M). The reduced
amount is calculated by the following expression based on the
surface area (S) of each sample for evaluation of corrosion
resistance before the immersion.
Reduced amount (g/m.sup.2)=.DELTA.M(g)/S(m.sup.2)
[0032] The results are shown in Table 4.
[0033] (Heated-sulfuric-acid-resistance test)
[0034] The samples of Examples, Comparative Examples, Reference
Examples and Conventional Examples for evaluation on corrosion
resistance each are immersed in 5% sulfuric acid solution at
240.degree. C. for 1 hour, and the reduced amount is determined by
calculation in the same manner as in the nickel-chloride-resistance
test. The results are shown in Table 4.
[0035] (Heated-hydrochloric-acid-resistance test)
[0036] The samples of Examples, Comparative Examples, Reference
Examples and Conventional Examples for evaluation on corrosion
resistance each are immersed in boiled 10% hydrochloric acid
solution for 1 hour, and the reduced amount is determined by
calculation in the same manner as in the nickel-chloride-resistance
test. The results are shown in Table 4.
[0037] (Clearance-corrosion-resistance test)
[0038] Two samples of each of Examples, Comparative Examples,
Reference Examples and Conventional Examples are overlapped each
other with the surfaces thereof facing each other, and are immersed
in 20% NaCl solution at 90.degree. C., adjusted to a pH value of 1
by hydrochloric acid, for 100 hours. Thus, the
clearance-corrosion-resistance test is performed. In the same
manner as in the nickel-chloride-resistance test, it is determined
as ".largecircle." for a sample in which no change is confirmed
between its surface conditions before and after the test, as
".smallcircle." for a sample in which increase of unevenness or the
like is slightly confirmed therebetween, and as ".DELTA." for a
sample in which increase of unevenness or the like is apparently
confirmed therebetween. The results are shown in Table 4.
TABLE-US-00004 TABLE 4 Heated- Heated- Hydro- Nickel- Sulfuric-
chloric- Clearance- Chloride- Acid- Acid Corrosion- Resistance
Resistance Resistance Resistance Surface Reduced Reduced Reduced
Surface Texture Amount Amount Amount Texture Ex. 1 .largecircle.
<0.10 0.76 1.5 .largecircle. Ex. 2 .largecircle. <0.10 0.61
1.8 .largecircle. Ex. 3 .largecircle. <0.10 0.65 1.7
.largecircle. Ref. Ex. 1 .largecircle. 0.1 0.86 1.9 .largecircle.
Ref. Ex. 2 .largecircle. <0.10 0.35 1.1 .largecircle. Ex. 4
.largecircle. <0.10 0.58 1.7 .largecircle. Ex. 5 .largecircle.
<0.10 0.58 1.6 .largecircle. Ref. Ex. 3 .largecircle. <0.10
0.36 1.2 .largecircle. Ref. Ex. 4 .largecircle. <0.10 0.42 1.3
.largecircle. Ref. Ex. 5 .largecircle. <0.10 0.46 1.4
.largecircle. Ex. 6 .largecircle. <0.10 0.57 1.4 .largecircle.
Ref. Ex. 6 .largecircle. <0.10 0.61 1.8 .largecircle. Ref. Ex. 7
.largecircle. <0.10 0.62 1.7 .largecircle. Ref. Ex. 8
.largecircle. <0.10 0.54 1.3 .largecircle. Ref. Ex. 9
.largecircle. <0.10 0.7 1.8 .largecircle. Ref Ex. 10
.largecircle. <0.10 0.51 1.5 .largecircle. Ref. Ex. 11
.largecircle. <0.10 0.58 1.3 .largecircle. Ref. Ex. 12
.largecircle. <0.10 0.6 1.4 .largecircle. Ex. 7 .largecircle.
<0.10 0.63 1.4 .largecircle. Ref. Ex. 13 .largecircle. <0.10
0.65 1.4 .largecircle. Ex. 8 .largecircle. <0.10 0.7 1.5
.largecircle. Ref. Ex. 14 .largecircle. <0.10 0.68 1.5
.largecircle. Ref. Ex. 15 .largecircle. <0.10 0.63 1.3
.largecircle. Ref. Ex. 16 .largecircle. <0.10 0.63 1.3
.largecircle. Ref. Ex. 17 .largecircle. <0.10 0.65 1.3
.largecircle. Ref. Ex. 18 .largecircle. <0.10 0.68 1.4
.largecircle. Ref. Ex. 19 .largecircle. <0.10 0.68 1.4
.largecircle. Ref. Ex. 20 .largecircle. <0.10 0.72 1.4
.largecircle. Ref. Ex. 21 .largecircle. <0.10 0.72 1.4
.largecircle. Com. Ex. 1 X 0.26 13.5 41.2 X Com. Ex. 2 .DELTA. 0.14
1.01 2.5 .DELTA. Com. Ex. 3 .DELTA. 0.15 1.25 3.5 .DELTA. Com. Ex.
4 .DELTA. 0.13 1.13 3.7 .DELTA. Com. Ex. 5 .DELTA. 0.14 1.01 2.5
.DELTA. Com. Ex. 6 .DELTA. 0.15 1.21 3.4 .DELTA. Com. Ex. 7 .DELTA.
0.25 1.81 4.2 .DELTA. Com. Ex. 8 .DELTA. 0.16 1.22 2.4 .DELTA. Com.
Ex. 9 .DELTA. 0.15 1.1 2.2 .DELTA. Com. Ex. 10 .DELTA. 0.13 1.05
2.1 .DELTA. Com. Ex. 11 .DELTA. 0.14 1.11 2.2 .DELTA. Conv. Ex. 1
.largecircle. <0.10 0.36 1.2 .largecircle. Conv. Ex. 2
.largecircle. <0.10 0.42 1.3 .largecircle. Conv. Ex. 3
.largecircle. <0.10 0.46 1.4 .largecircle. Conv. Ex. 4
.largecircle. <0.10 0.57 1.4 .largecircle. *The "reduced amount"
in each test is given in g/m.sup.2. The "<0.10" is meant that
the reduced amount is less than 0.10 g/m.sup.2.
[0039] From Table 4, it is also appreciated that a titanium alloy
for corrosion-resistant materials containing 0.01-0.12% by mass in
total of at least one of platinum group elements, at least one of
Al, Cr, Zr, Nb, Si, Sn and Mn, in which at least one of Sn and Mn
is included, and the residue comprising Ti and impurities, in which
the total content of Al, Cr, Zr, Nb, Si, Sn and Mn is 5% by mass or
less, or a titanium alloy for corrosion-resistant materials
containing 0.01-0.12% by mass in total of at least one of platinum
group elements, 0.05-2.00% by mass in total of any one or both of
Co and Ni, at least one of Al, Cr, Zr, Nb, Si, Sn and Mn, in which
at least one of Sn and Mn is included, and the residue comprising
Ti and impurities, in which the total content of Al, Cr, Zr, Nb,
Si, Sn and Mn is 5% by mass or less, is excellent in corrosion
resistance compared with the respective Comparative Examples, and
has corrosion resistance equivalent to that of a conventional
titanium alloy for corrosion-resistant materials using sponge
titanium.
[0040] In other words, it is appreciated that the titanium alloy
for corrosion-resistant materials of the present invention is
capable of suppressing deterioration of corrosion resistance even
though it uses recycled titanium alloys or the like, and thus being
produced at low cost while maintaining the capability to suppress
the deterioration of corrosion resistance.
* * * * *