JP2011246763A - SURFACE TREATED Ti MATERIAL, AND MANUFACTURING METHOD THEREFOR - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a separator material for a fuel cell, capable of forming firmly and uniformly a layer containing Au, while reducing a deposit amount of the Au onto a Ti base material surface, and capable of securing close contact property and corrosion resistance required in a separator for the fuel cell.SOLUTION: A surface layer 6 containing Au and Cr is formed on the surface of a Ti base material 2, an intermediate layer 2a containing respectively Ti and O of 10 atm.% or more, the Au less than 20 atm.% and the Cr of 20 atm.% or more, exists at 1 nm or more of thickness between the surface layer and the Ti base material, the deposit amount of Au is 4,000 ng/cmor more and less than 70,000 ng/cm, and a thickness part tcontaining Cr of 20 atm.% or more is 30% or more with respect to total thickness tof the surface layer and the intermediate layer, in this surface treated Ti material.

Description

  The present invention relates to a surface-treated Ti material that can be suitably used for a fuel cell separator material and the like and on which Au or an Au alloy (a layer containing Au) is formed, and a method for manufacturing the same.

Titanium is one of the metals often used in corrosive environments as an element with excellent corrosion resistance. However, titanium itself has a low electrical conductivity, and further has a high contact resistance because an oxide layer is formed on the surface thereof. Therefore, it is difficult to use it in a region where another member is brought into contact with titanium to ensure conductivity.
Therefore, it is known to reduce the contact resistance by applying wet gold plating to the titanium substrate. Further, a technique is known in which a noble metal selected from Au, Ru, Rh, Pd, Os, Ir, Pt, and the like is formed on a Ti surface by sputtering (Patent Document 1). Further, Patent Document 1 describes that the oxide of the noble metal is formed on the Ti surface.
On the other hand, a technique is known in which an Au film is formed on an oxide film of a Ti substrate via an intermediate layer made of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, or the like (patent) Reference 2). This intermediate layer has good adhesion to the base oxide film, that is, good bonding with O (oxygen atom), and good adhesion and bonding to the Au film because of the metal or metalloid. .
Further, on the surface of the Ti base material, an alloy layer of Au and a first component made of a noble metal that is more oxidizable than at least one selected from the group consisting of Ru, Rh, Pd, Ir, Os, and Pt, Or an Au single layer is formed,
A technique is known in which an intermediate layer of 1 nm or more containing 10% or more of Ti and O and 20% or more of the first component exists between the alloy layer or the Au single layer and the Ti base material. (Patent Document 3).

JP 2001-297777 A JP 2004-185998 A JP 2009-35748 A

However, in the case of wet gold plating, if the electrodeposition shape of gold plating is granular and the amount of gold plating is small, a portion that becomes a non-plated portion is formed on a part of the surface of the titanium substrate. Therefore, in order to uniformly plate the entire surface of the titanium base material with gold, it is necessary to increase the adhesion amount of Au.
In the case of the technique described in Patent Document 1, in order to obtain an Au alloy film with good adhesion, it is necessary to remove the oxide film on the surface of the titanium substrate. If the oxide film is not sufficiently removed, the precious metal film There is a problem that the adhesion is lowered.
In the case of the titanium material described in Patent Document 2, if the surface treatment layer or the intermediate layer is thin, the wear resistance may not be sufficient. On the other hand, when the Au layer is thin and the metal constituting the intermediate layer is thick, the wear resistance is good, but the conductivity may not be sufficient depending on the metal of the intermediate layer.

  That is, the present invention has been made to solve the above-described problems, and aims to provide a surface-treated Ti material having a surface layer having high conductivity and high wear on the surface of a titanium base material, and a method for producing the same. And

As a result of various studies, the inventors have formed a surface layer containing Au and Cr on the surface of the Ti base material, and further formed an intermediate layer containing Ti, O and Cr, and the total thickness of the surface layer and the intermediate layer. It has been found that by defining the Cr content of the portion, a surface layer having conductivity and wear resistance can be obtained.
In order to achieve the above object, in the surface-treated Ti material of the present invention, a surface layer containing Au and Cr is formed on the surface of a Ti base material, and a Ti layer is formed between the surface layer and the Ti base material. And O are each 10 atomic% or more, an intermediate layer of less than 20 atomic% of Au and 20 atomic% or more of Cr is present in an amount of 1 nm or more, and an adhesion amount of Au is 4000 ng / cm ² or more and less than 70000 ng / cm ² , The thickness portion containing 20 atomic% or more of Cr accounts for 30% or more of the total thickness of the intermediate layer.

It is preferable that the adhesion amount of Cr is 200 ng / cm ² or more.
The Ti base material may be formed by forming a Ti film having a thickness of 10 nm or more on the surface of a base material different from Ti.

The method for producing a surface-treated Ti material according to the present invention is a method for producing the surface-treated Ti material, in which Cr is dry-formed on the surface of the Ti substrate, and then Au is dry-formed.
The dry film formation is preferably sputtering.

  According to the present invention, it is possible to form a layer containing Au firmly and uniformly on Ti while reducing the adhesion amount of Au, and to improve conductivity, corrosion resistance, and wear resistance.

It is a schematic diagram which shows the structure of the surface treatment Ti material which concerns on embodiment of this invention. 3 is a diagram showing an XPS image of a cross section of the surface-treated Ti material of Example 1. FIG.

Hereinafter, the surface-treated Ti material according to the embodiment of the present invention will be described. In the present invention,% means atomic (at)% unless otherwise specified.
In addition, the surface-treated Ti material of the present invention has electrical conductivity, and has been used as a decorative product, which is the application of materials coated with Au, as well as semiconductor parts, aerospace material parts, automobile parts, sensors, and measurement. It can be used for equipment parts, terminals, electrical contact parts, electrode materials and the like.
In addition, the present invention can be used as a fuel cell separator in that the materials are used in contact with each other and maintain conductivity while being excellent in wear resistance.

  As shown in FIG. 1, the surface-treated Ti material has an intermediate layer 2a formed on the surface of a Ti base 2 and a surface layer 6 formed on the surface of the intermediate layer 2a.

<Ti substrate>
The surface-treated Ti material of the present invention can be used without problems in practical use under a general environment. However, since the corrosion resistance of the Ti base material itself is good, it is used under a corrosive environment or a corrosive environment. There is expected.
The Ti substrate may be a solid titanium material, or may be a Ti substrate having a thickness of 10 nm or more formed on the surface of a substrate different from Ti. Examples of the base material different from Ti include stainless steel, aluminum, copper, and the like. By covering these surfaces with Ti, the corrosion resistance of stainless steel, aluminum, copper, etc., which has lower corrosion resistance than titanium, can be improved. it can. However, the corrosion resistance improving effect cannot be obtained unless Ti is covered by 10 nm or more.
The material of the Ti base material 2 is not particularly limited as long as it is titanium. Further, the shape of the Ti base material 2 is not particularly limited as long as it is a shape capable of sputtering Cr and gold. However, considering press forming into a separator shape, the shape of the Ti base material is preferably a plate material. The thickness of the entire Ti substrate is preferably 10 μm or more.
O (oxygen) contained in the intermediate layer 2a is naturally formed by leaving the Ti base 2 in the air, but O may be positively formed in an oxidizing atmosphere.

The Ti concentration is detected by XPS concentration detection, which will be described later, and the concentration of each element is analyzed with the total of the designated elements as 100%. The depth of 1 nm from the outermost surface of the surface-treated Ti material is a distance (distance in terms of SiO ₂ ) on the horizontal axis (thickness direction) of the chart by XPS analysis.

<Surface layer>
A surface layer 6 containing Cr and Au is formed on the Ti base 2. This surface layer is for imparting Au characteristics (conductivity) and abrasion resistance to the Ti substrate, and also imparts corrosion resistance and hydrogen embrittlement resistance depending on the application.
Cr is a) easy to bond with oxygen, and forms an intermediate layer to improve the adhesion between the surface layer and the Ti base material, b) ensures the adhesion with Au by constituting an alloy with Au, c) a hard layer obtained by alloying; d) a surface treatment layer having a property that the conductivity of the layer containing Cr is not significantly reduced compared to Au, and maintaining the conductivity while being wear resistant. Can be configured. Cr is excellent in corrosion resistance and hardly absorbs hydrogen.
Zr, Hf, V, Nb, Ta, Mo, and W are also elements that easily bond to oxygen and are alloyed with Au. However, in the case of Zr, Hf, and V, the conductivity of the layer alloyed with Au is Au. Compared to the conductivity of the alloy layer of Cr and Cr. Moreover, W is expensive and the cost becomes high. In the case of Nb, Ta, and Mo, corrosion resistance comparable to Cr cannot be obtained particularly when Au is thin.
Ru, Rh, Pd, Ir, Os, and Pt are also elements that easily bond to oxygen and alloy with Au. However, the hardness of the layer in which Ru, Pd, or Pt is alloyed with Au is softer than the hardness of the alloy layer of Au and Cr, and the wear resistance is inferior to that of the alloy layer of Au and Cr. Rh, Ir, and Os are expensive and expensive.

  The surface layer can be confirmed by XPS analysis which will be described later, and is a portion containing Au and Cr from the outermost surface to the lower layer by XPS analysis, and a portion located above the following intermediate layer (Au 20% or more (Part) is a surface layer. The thickness of the surface layer is preferably 3 to 100 nm. If the thickness of the surface layer is less than 3 nm, the corrosion resistance required for the fuel cell separator may not be ensured on the Ti substrate. The thickness of the surface layer is more preferably 5 nm or more, and further preferably 10 nm or more.

  An Au single layer may be formed on the outermost surface layer 6. The Au single layer is a portion where the concentration of Au is almost 100% by XPS analysis.

<Intermediate layer>
By XPS analysis between the surface layer (or Au single layer) 6 and the Ti substrate 2, the intermediate layer 2a with Ti and O of 10 atomic% or more, Au of less than 20 atomic% and Cr of 20 atomic% or more is 1 nm or more. Exists. The upper limit of the thickness of the intermediate layer is not limited, but is preferably 100 nm or less from the viewpoint of the cost of Cr.
Usually, a Ti substrate has an oxide layer on the surface, and it is difficult to directly form an Au (containing) layer that is difficult to be oxidized on the Ti surface. On the other hand, it is considered that the metal is more easily oxidized than Au, and forms an O atom and an oxide in the Ti oxide on the surface of the Ti base, and is firmly bonded to the surface of the Ti base.
The intermediate layer preferably does not contain Au, and if 20% or more of Au is contained, the adhesion decreases. In order to reduce the Au concentration in the intermediate layer to less than 20%, it is preferable to perform sputtering using a Cr single target or a low Au concentration Cr—Au alloy target on the Ti substrate.

Here, a depth profile by XPS (X-ray photoelectron spectroscopy) analysis is measured, and concentration analysis of Au, Ti, O, Cr is performed to determine the layer structure of the sputtered layer. In the concentration detection by XPS, the concentration of each element is analyzed with the total of designated elements as 100%. In the XPS analysis, the distance of 1 nm in the thickness direction is the distance on the horizontal axis of the chart by XPS analysis (distance in terms of SiO ₂ ).

  The reason why the lower limit of Ti and O is 10% and the lower limit of Cr is 20% is that the part where Cr is less than 20% is close to the surface of the Ti substrate, and the part where Ti is less than 10% is the surface layer. This is because the portion where O is less than 10% does not form a sufficient oxide with Cr and Ti and does not function as an intermediate layer. Moreover, since Ti and O each decrease rapidly from 10%, the lower limit is 10% from the measurement. The reason for making Au less than 20% is to improve adhesion. When the intermediate layer is less than 1 nm, Cr is thin and the portion where the Ti base material and Au are in contact with each other increases, so that the adhesion of the surface layer may deteriorate.

In the surface-treated Ti material of the present invention, the adhesion amount of Au needs to be 4000 ng / cm ² or more.
When the adhesion amount of Au is less than 4000 ng / cm ² , the conductivity and corrosion resistance required for the fuel cell separator cannot be secured, and the contact resistance increases. From the viewpoint of saving money, the adhesion amount of Au is less than 70000 ng / cm ² , preferably 40000 ng / cm ² or less, more preferably 20000 ng / cm ² or less. The adhesion amount of Au of 70,000 ng / cm ² corresponds to the thickness of pure Au of 30 nm.
In the surface-treated Ti material of the present invention, the amount of Cr deposited needs to be 200 ng / cm ² or more.
When the adhesion amount of Cr is less than 200 ng / cm ² , the adhesion of the surface layer is deteriorated because Cr is small.

In the surface-treated Ti material of the present invention, the thickness portion containing 20 atomic% or more of Cr accounts for 30% or more of the total thickness of the surface layer and the intermediate layer by XPS analysis in the thickness direction.
Cr is a relatively hard metal (high Vickers hardness), while Au is a soft metal. Therefore, if the film containing Au contains a large amount of Cr (the thickness portion containing 20 atomic% or more of Cr occupies 30% or more), the hardness of the film is improved, and as a result, the wear resistance is improved.

In the present invention, it is preferable that an oxide layer containing less than 100% Ti and 20% or more O is formed between the Ti base material and the surface layer 6 with a thickness of less than 100 nm (this oxide layer). Part of it may overlap the middle layer area).
When the oxide layer is present, the titanium base material is prevented from becoming brittle when a continuous power generation test of the fuel cell is performed.
Here, the region where Ti is less than 50% is regarded as a portion different from the titanium base material because the Ti concentration is ½ or less of the whole. Since an oxide film exists on the surface of the Ti base material, a portion from a thickness portion where Ti is less than 50% to the surface layer is defined as an oxide layer. Also, the reason why the region containing 20% or more of O is used as the oxide layer is that when the O (oxygen) concentration of the oxide layer is less than 20%, the Ti base material becomes brittle when the continuous power generation test of the fuel cell is performed. This is because the durability of the surface-treated Ti material deteriorates.
However, when the thickness of the oxide layer is 100 nm or more, the adhesion and conductivity of the surface layer may decrease. On the other hand, when the oxide layer is thin, the titanium base material becomes brittle when the continuous power generation test of the fuel cell is performed, and the durability as the surface-treated Ti material may be deteriorated. Therefore, the thickness of the oxide layer is preferably 5 nm or more, more preferably 10 nm or more.

It is preferable to have a gradient composition in which the proportion of Au in the surface layer increases from the lower layer side toward the upper layer side. Here, the ratio of Au can be obtained by the XPS analysis described above. The thickness of the surface layer is the actual size of the scanning distance in XPS analysis.
When the surface layer has a gradient composition, the proportion of Cr that is more oxidizable than Au increases on the lower layer side of the surface layer, and the bond with the Ti substrate surface becomes stronger, while the upper layer side of the surface layer has the characteristics of Au. Since it becomes stronger, corrosion resistance and durability are improved.

<Manufacture of surface-treated Ti material>
As a method of forming the intermediate layer of the surface-treated Ti material, the surface Ti oxide film of the Ti base material is not removed, and sputtering is performed on this base material using Cr as a target, so that the O in the surface Ti oxide film is formed. Cr can be bonded to form an intermediate layer. Also, after removing the surface Ti oxide film of the Ti base material 2, sputtering film formation is performed using the Cr oxide as a target, or after removing the surface Ti oxide film of the Ti base material 2, sputtering is performed using Cr as a target in an oxidizing atmosphere. The intermediate layer can also be formed by forming a film.
During sputtering, the surface Ti oxide film on the Ti base material may be appropriately removed, and reverse sputtering (ion etching) may be performed for the purpose of cleaning the base material surface. Reverse sputtering can be performed, for example, by irradiating the substrate with argon gas at an output of about RF 100 W and an argon pressure of about 0.2 Pa.
The Au of the intermediate layer is contained in the intermediate layer by Au atoms entering the intermediate layer by Au sputtering for forming the following surface layer. Alternatively, a sputtering film may be formed on the surface of the Ti substrate using an alloy target containing Cr and Au.

As a method for forming the surface layer, for example, Cr can be deposited on a Ti base material by sputtering as described above, and then Au can be deposited by sputtering on the Cr film. In this case, since the sputtered particles have high energy, even if only the Cr film is formed on the surface of the Ti base, by sputtering Au there, Au enters the Cr film and becomes a surface layer. Further, in this case, the composition is a gradient composition in which the proportion of Au in the surface layer increases from the lower layer side toward the upper layer side.
Sputter film formation may be first performed on the Ti substrate surface using an alloy target having a low Au concentration of Cr and Au, and then using an alloy target having a high Au concentration of Cr and Au.

  In the XPS analysis in the thickness direction, as a method of making the thickness part of 30% or more of the total thickness of the surface layer and the intermediate layer contain 20 atomic% or more of Cr, the thickness of Cr formed during sputtering is compared with that of Au And thickening. Preferably, (Au thickness / Cr thickness) is 10 or less.

  According to the surface-treated Ti material according to the embodiment of the present invention, a layer containing Au can be formed firmly and uniformly on Ti, and this layer has conductivity, corrosion resistance, and durability. Further, according to the embodiment of the present invention, if a layer containing Au is sputter-deposited, this layer becomes a uniform layer. Therefore, the surface becomes smoother than wet gold plating, and Au is not wasted. There is an advantage that it can be done.

<Preparation of sample>
As a Ti base material, an industrial pure titanium material (JIS type 1) having a thickness of 100 μm was used, and pretreatment was performed by FIB (focused ion beam processing). When observed by energy dispersive X-ray fluorescence (EDX) analysis using FE-TEM (electrolytic emission transmission electron microscope), it was confirmed that a titanium oxide layer of about 10 nm was formed on the surface of the Ti substrate in advance. did.
In some examples, a 100 μm thick industrial pure stainless steel material (SUS316L) or a 100 μm thick pure copper (C1100) coated with Ti having a predetermined thickness shown in Table 1 (Ti coating material) was used. The Ti coating was performed by vacuum vapor deposition using an electron beam vapor deposition apparatus (manufactured by ULVAC, MB05-1006).
Next, Cr was formed on the surface of the titanium oxide layer of the Ti base so as to have a predetermined target thickness by sputtering. Pure Cr was used for the target. Next, Au was deposited using a sputtering method so as to have a predetermined target thickness. Pure Au was used for the target.
The target thickness was determined as follows. First, an object (Cr, Au) is formed in advance on a titanium substrate by sputtering, and the actual thickness is measured with a fluorescent X-ray film thickness meter (SEA Instruments 100A, collimator 0.1 mmΦ) manufactured by Seiko Instruments. The sputter rate (nm / min) was grasped. Based on the sputtering rate, the sputtering time for a thickness of 1 nm was calculated, and sputtering was performed under these conditions.
Sputtering of Cr and Au was performed using a sputtering apparatus manufactured by ULVAC, Inc. under the conditions of an output DC of 50 W and an argon pressure of 0.2 Pa.

<Measurement of layer structure>
About the obtained sample, the depth (Depth) profile by XPS (X-ray photoelectron spectroscopy) analysis was measured, the density | concentration analysis of Au, Ti, O, and Cr was performed, and the layer structure of the sputter | spatter layer was determined. As an XPS device, ULVAC-PHI Co., Ltd. 5600MC was used, ultimate vacuum: 6.5 × 10 ⁻⁸ Pa, excitation source: monochromatic AlK, output: 300 W, detection area: 800 μmΦ, incident angle: 45 degrees, The take-off angle was 45 degrees, no neutralization gun was used, and the measurement was performed under the following sputtering conditions.
Ion species: Ar +
Acceleration voltage: 3 kV
Sweep area: 3mm x 3mm
Rate: 2 nm / min. (SiO ₂ equivalent)
The concentration detection by XPS was performed by analyzing the concentration (at%) of each element with the total of designated elements as 100%. In the XPS analysis, the distance of 1 nm in the thickness direction is the distance on the horizontal axis of the chart by XPS analysis (distance in terms of SiO ₂ ).

FIG. 2 shows an XPS image of a cross section of the sample of Example 1.
A surface layer 6 containing Cr and Au is formed on the surface of the Ti base 2. Further, it can be seen that an intermediate layer 2a of Ti and O of 10 atomic% or more, Au of less than 20 atomic% and Cr of 20 atomic% or more is present at 1 nm or more between the Ti substrate 2 and the surface layer 6.
Further, XPS analysis in the thickness direction shows that the thickness portion t _B containing 20 atomic% or more of Cr occupies 30% or more of the total thickness t _A of the surface layer and the intermediate layer.
In the present invention, the concentration of Ti, O, etc. is defined in order to define the intermediate layer. Therefore, since the boundary of the intermediate layer is determined by the Ti and O concentrations for convenience, a layer different from both the intermediate layer and the Ti substrate may be interposed between the intermediate layer and the upper and lower layers (for example, the Ti substrate 2). is there.

<Preparation of each sample>
Samples of Examples 1 to 8 were prepared by variously changing the target thicknesses of the Cr film and Au film at the time of sputtering for titanium substrates (pure Ti and Ti coating materials) having different thicknesses of the initial surface Ti oxide layer. did.

As Comparative Example 9, only an Au film was formed.
As Comparative Example 10, a sample was prepared by reducing the sputtering thickness of the Cr film to 0.25 nm.
As Comparative Example 11, a sample was prepared by reducing the sputtering thickness of the Au film to 3 nm and reducing the sputtering thickness of the Cr film to 0.25 nm.
As Comparative Example 12, a sample was manufactured by increasing the sputtering thickness of the Au film to 15 nm.
As Comparative Example 13, a sample was manufactured by increasing the sputtering thickness of the Au film to 30 nm.
As Comparative Example 14, a sample was manufactured in the same manner as in Example 1 except that the sputtering thickness of the Au film was reduced to 2 nm.

As Reference Example 15, an Au layer corresponding to 5 nm was formed on the surface of the Ti substrate by wet plating instead of sputtering. In wet plating, the substrate was immersed, degreased, washed with water, pickled, washed with water, activated, and washed with water, then plated with gold in a sulfite-based plating bath, and further washed with water and heat-treated.
As Reference Example 16, a sample was prepared in the same manner as in Example 1 except that Ti was deposited instead of Cr during sputtering.
As Reference Example 17, a sample was prepared in the same manner as in Example 1 except that Ta was deposited instead of Cr during sputtering.
As Reference Example 18, a sample was prepared in the same manner as in Example 1 except that Mo was deposited instead of Cr during sputtering.
As Reference Example 19, a sample was prepared in the same manner as in Example 1 except that Pd was deposited instead of Cr during sputtering.

<Evaluation>
The following evaluation was performed for each sample.
A. Adhesion of coating After marking the grids on the outermost surface (surface layer) of each sample at intervals of 1 mm, stick adhesive tape, and bend each specimen 180 ° to return it to its original state. A peel test was performed to quickly and strongly peel the tape.
The case where there was no peeling at all was marked as ◯, and the case where some peeling was visually observed was marked as x.
B. Film formation shape A STEM image of a cross section of each sample was taken, and a case where an uneven structure in which particles of several to several hundreds of nanometers were collected was observed to be granular, and a case where the surface was smoother than a particle was layered.
The STEM used was model number HD-2000 manufactured by Hitachi, Ltd., and an accelerating voltage of 200 kV and a visual field width of 50 nm were measured for three visual fields per sample.

C. Amount of deposition The amount of deposition of Au and Cu on one side of the sample was evaluated by dissolving a total amount of a 50 mm × 50 mm sample in a hydrofluoric acid solution and analyzing it by ICP (inductively coupled plasma) emission spectroscopy. Note that the number of samples was five, and a value obtained by averaging these values was adopted.

D. Conductivity (contact resistance)
The contact resistance was measured by applying a load to the entire sample surface. First, carbon papers were laminated on the front and back sides of a 40 × 50 mm plate-like sample, and Cu / Ni / Au plates were further laminated on the outer sides of the front and back carbon papers. The Cu / Ni / Au plate is a material in which a 10 μm thick copper plate is plated with a 1.0 μm thick Ni base, and the Ni layer is plated with a 0.5 μm Au plate. The carbon paper was placed in contact with it.
Further, a Teflon (registered trademark) plate was arranged outside the Cu / Ni / Au plate, and a load of 10 kg / cm ² was applied in the compression direction from the outside of each Teflon (registered trademark) plate with a load cell. In this state, when a constant current with a current density of 100 mA / cm ² was passed between the ^two Cu / Ni / Au plates, the electrical resistance between the Cu / Ni / Au plates was measured by a four-terminal method.

E. Abrasion resistance Abrasion resistance is determined by rubbing both samples with the surface layer of two test pieces facing each other with an abrasion tester, and comparing the amount of each sample before rubbing with the amount of each sample after the abrasion test. It was evaluated by doing. (Attachment amount after abrasion test / attachment amount before abrasion test) = 0.95 or more was regarded as good abrasion resistance. In addition, the adhesion amount of Au and Cr is an average of the adhesion amount of the two test pieces which oppose.
The wear test conditions are as follows.
Device name: Shinto Science Co., Ltd. TYPE36
Applied load: 0.01kgf
Friction speed: 0.001m / S
Reciprocating stroke: 30mm
Specimen area: 30 x 30 mm
Number of reciprocations: 100 times / measurement Number of samples to be measured per specification: 10

  The obtained results are shown in Tables 1 and 2. The presence of the intermediate layer was confirmed by obtaining the ratio of each component from the actual XPS image of the sample cross section.

As is clear from Table 1 and Table 2, the surface layer and the intermediate layer are present on the Ti base material, the adhesion amount of Au is 4000 ng / cm ² or more and less than 70000 ng / cm ² , and by XPS analysis in the thickness direction, the total thickness t _a of the surface layer and the intermediate layer, in the case of each embodiment thickness portion t _B containing Cr 20 atomic% or more accounts for more than 30%, were excellent in adhesion, conductivity and abrasion resistance .

On the other hand, in the case of Comparative Example 9 in which no Cr film was formed, the adhesion was deteriorated and the conductivity and wear resistance could not be evaluated.
In Comparative Examples 10 and 11 where the sputtering thickness of the Cr film was reduced to 0.25 nm, the Cr adhesion amount was less than 200 ng / cm ² , and the intermediate layer thickness was less than 1 nm, which deteriorated the adhesion of the sputtering film. . Also, the conductivity and wear resistance could not be evaluated.
In Comparative Examples 12 and 13, in which the sputtering thickness of the Au film was thicker than that of the example, the ratio of t _B to t _A was less than 30%, and the wear resistance was deteriorated.
In the case of the comparative example 14 in which the sputtering thickness of the Au film was thinner than that of the example, the conductivity was deteriorated.

In the case of Reference Example 15 in which Au was deposited to a thickness of 5 nm by wet plating, the wear resistance was deteriorated. This is probably because Cr is not contained in the plating film of wet plating, and the hardness of the film is low.
In each of Reference Examples 16 to 19 in which Ti, Ta, Mo, and Pd were formed in place of Cr, the wear resistance deteriorated in all cases.

2 Ti substrate 2a Intermediate layer 6 Surface layer t Total thickness of surface layer _A and intermediate layer t _B Thickness portion containing 20 atomic% or more of Cr

Claims (5)

A surface layer containing Au and Cr is formed on the surface of the Ti substrate,
Between the surface layer and the Ti base material, Ti and O are each 10 atomic% or more, an intermediate layer of less than 20 atomic% of Au and 20 atomic% of Cr or more exists 1 nm or more,
Au deposition amount is 4000 ng / cm ² or more and less than 70000 ng / cm ² ,
A surface-treated Ti material in which a thickness portion containing 20 atomic% or more of Cr accounts for 30% or more with respect to the total thickness of the surface layer and the intermediate layer. The surface-treated Ti material according to claim 1, wherein the amount of Cr deposited is 200 ng / cm ² or more.   The surface-treated Ti material according to claim 1, wherein the Ti base material is formed by forming a Ti film having a thickness of 10 nm or more on a base material surface different from Ti. It is a manufacturing method of the surface treatment Ti material in any one of Claims 1-3,
A method for producing a surface-treated Ti material, in which Cr is dry-deposited on the surface of the Ti substrate, and then Au is dry-deposited.   The method for producing a surface-treated Ti material according to claim 4, wherein the dry film formation is sputtering.

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