JPH0835074A - Member made of titanium or titanium alloy excellent in wear resistance and erosion resistance and its production - Google Patents

Abstract

PURPOSE:To produce a Ti-base member excellent in wear resistance and erosion resistance, on the surface of a base material constituted of a Ti-base metal, by forming a coating layer constituted of a metallic material and baron in which the dispersing rate of boron is higher than that in the base material into a specified thickness. CONSTITUTION:On the surface of a base material constituted of Ti or a Ti alloy, a metal-coating layer constituted of a metallic material in which the dispersing rate of baron is higher than that in the base material is formed. boron After that, this material is subjected to alloying treatment with boron to disperse boron into the metal coating layer. Then, the coating layer constituted of the metallic material and baron in which the dispersing rate of boron is higher than that in the base material is formed into >=10mum-thickness. As the metal for forming the coating layer, one or more kinds among Fe, Co, Ni, Cr, Mo and W are preferably used, and moreover, the contents of Fe, Co and Ni are preferably regulated to >=90 atomic %.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Ti or Ti alloy member excellent in wear resistance and melting resistance and a method for manufacturing the same, and more particularly to sliding wear, rolling wear, line-to-line wear and the like. A member made of Ti or a Ti alloy having excellent wear resistance, such as a bicycle pedal bearing or a crankshaft,
Members such as automobile engine valves, cylinders, coil springs, retainers, connecting rods, shaft materials that come into contact with bearings, members that come into contact with power transmission parts such as gears, and forming rolls used under high surface pressure, or high temperature regions The present invention relates to a Ti or Ti alloy member suitable for use as a jet engine member and the like and a method for manufacturing the same.

Further, the above Ti or Ti alloy member is
When it is used for a die casting die and its parts, for example, a die material such as a plunger sleeve, a plunger tip, a core pin, and a sprue, it exhibits excellent erosion resistance.

[0003]

2. Description of the Related Art In the field of transportation machines such as automobiles and airplanes, further weight reduction is required, and use of Ti and Ti alloys which are lightweight and have excellent corrosion resistance is being studied. However, since Ti and Ti alloy members have low surface hardness, there is a problem in terms of wear resistance.

In recent years, Ti alloys such as Ti-6Al-V, which are excellent in lightness and heat retention, have been regarded as promising as a die material from the viewpoint of improving the yield and quality of die cast products. However, the Ti alloy has a problem that it has a high reactivity with molten aluminum and is poor in melting resistance.

Techniques for improving wear resistance and erosion resistance include surface hardening treatment methods such as carburizing treatment, nitriding treatment and boration treatment. Among them, the boration treatment is a method of forming a boron on a metal surface. The hardness of the chemical conversion layer is high, and excellent abrasion resistance and melting resistance are exhibited, which is preferable. However, the thickness of the boride layer obtained by subjecting Ti or Ti alloy to the boration treatment is, for example, about 10 μm in the case of pure Ti, and about several μm in the case of Ti alloy such as Ti-6Al-V. It has only the thickness of Ti or Ti or Ti
There is a problem that sufficient abrasion resistance and melting resistance cannot be obtained even if the alloy is subjected to boration treatment.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a Ti or Ti alloy member excellent in wear resistance and melt damage resistance, and a manufacturing method thereof. To do.

[0007]

The Ti or Ti alloy member of the present invention which has solved the above-mentioned problems is a metal material having a diffusion rate of boron higher than that of the base metal on the surface of the base material made of Ti or Ti alloy. Coating layer consisting of boron and boron is 10 μm
The gist of the invention is to be formed with the above thickness.

The metal material forming the coating layer is preferably one or more metals selected from the group consisting of Fe, Co, Ni, Cr, Mo and W. Further, Fe, Co, It is desired that the Ni content be 90 atomic% or more.

The concentration of boron contained in the coating layer is preferably 1 atomic% or more, and the concentration of boron contained in the coating layer is higher on the surface side of the coating layer than on the base metal side. It is preferable to raise it.

The following methods (1) to (3) are recommended for manufacturing the above Ti or Ti alloy member. (1) After forming a metal coating layer made of a metal material having a diffusion rate of boron higher than that of the base metal on the surface of the base material by a wet plating method or a magnetron sputtering method,
A method of diffusing boron into the metal coating layer by performing boration treatment. (2) A method of forming a coating layer composed of the above metal material and boron by a magnetron sputtering method using a target having a composition corresponding to the coating layer. (3) A method of forming a coating layer made of the above metal material and boron by a reactive sputtering method in a boride gas atmosphere, using the metal material forming the coating layer as a target.

[0011]

The present inventors conducted various studies on the surface hardening treatment for the purpose of developing a Ti or Ti alloy member excellent in wear resistance and melting resistance, and as a result, Ti or Ti alloy
Focusing on the very low diffusion rate of boron in the alloy,
Rather than directly subjecting the surface of the base material made of Ti or Ti alloy to boration treatment, first, Ti or Ti is applied to the surface of the base material.
If a coating layer made of a metal material having a higher boron diffusion rate than the alloy is formed and the coating layer is subjected to a boriding treatment, Ti or T
It was found that a borated layer having a thickness of 10 μm or more can be formed on the surface of the i alloy member, and a Ti or Ti alloy member that can exhibit sufficient wear resistance and melt damage resistance can be obtained. However, the Ti or Ti alloy member of the present invention,
It is not limited by the above manufacturing method, but Ti
Alternatively, a coating layer made of boron and a metal material having a higher boron diffusion rate than the base material may be formed on the surface of the base material made of a Ti alloy.

Fe, Co, Ni and C are metallic materials having a higher boron diffusion rate than Ti or Ti alloy.
r, Mo, W and the like can be exemplified, and particularly preferable are Fe and C.
O and Ni, and the content of these three elements is preferably 90 atom% in the metal material, and more preferably 95 atom% or more.

In the present invention, the thickness of the borated layer capable of exhibiting sufficient wear resistance and erosion resistance is 10 μm or more, but considering that it is used as a member having a high surface pressure, 20 μm or more is preferable, 50 μm or more is more desirable.

Further, in the present invention, in order to exert sufficient wear resistance and erosion resistance, it is necessary to form a sufficient amount of boride in the coating layer, and the boron concentration in the coating layer. Is preferably 1 atomic% or more. Incidentally, it is more preferably 5 at% or more, while the upper limit is preferably 30 at% and more preferably 50 at% or less.

Further, it is desirable that the concentration of boron contained in the coating layer is gradually or gradually increased toward the surface, and the surface layer portion of the coating layer has high hardness to exhibit excellent wear resistance. The boron concentration at the interface with the base material can be reduced to form a coating layer having excellent adhesion to the base material.

The present invention does not limit the method of manufacturing the above Ti or Ti alloy member, but it is recommended to first coat the metal layer and then perform the boration treatment. According to this method, a diffusion layer is formed at the interface between the coating metal layer and the Ti alloy base material during the boration treatment, so that the adhesiveness is remarkably improved and the heat cycle property is also improved.

Note that the present invention does not limit the method of subjecting the above-mentioned coated metal layer to the boration treatment, and well-known boron treatment such as boration treatment with a molten salt or powder paste, boration treatment using a gas such as BCl ₃ or the like. A chemical treatment method may be adopted. The boration treatment can be performed in the temperature range of 600 to 1100 ° C., and the heating time may be 2 to 10 hours. Alternatively, boron may be diffused into the metal layer by ion implantation.

Further, the present invention does not limit the method for coating the metal layer, and includes wet plating, as well as vapor phase coating such as sputtering, ion plating, CVD and thermal spraying. It is suitable for the reason. That is, many parts used as wear resistant parts have complicated shapes such as engine valves, cylinders, coil springs, retainers, connecting rods, and the like. By adopting the wet plating method, it becomes easy to uniformly form a film on a member having a complicated shape. The wet plating method can be roughly divided into electroless plating and electroplating. Electroless plating is excellent in that the adhesion of the coating layer is high, while electroplating is advantageous in controlling the film thickness.

In producing the Ti or Ti alloy member of the present invention, a method of forming a coating layer composed of a metal material and boron by a magnetron sputtering method using a target having a composition corresponding to the coating layer, A method of forming the coating layer by a reactive sputtering method in a boride gas atmosphere using a metal material as a target may be adopted.

For the purpose of improving various characteristics of the coating (hardness, corrosion resistance, etc.), an additive element is added to the metal coating layer formed on the base material within a range not lowering the diffusion rate of boron as compared with Ti. May be.

[0021]

Example 1 A film having the chemical composition shown in Table 1 was formed by the following film forming method using Ti-6Al-4V as a base material. The compound composition of the outermost surface and the thickness of the film are also shown in Table 1.

Film forming method (1): Test piece No. For Nos. 1 to 3, films were formed by the RF magnetron sputtering method using targets having a composition corresponding to the metal boride coating the surface of the base material. No. No. 1 uses a boride Ni target, and No. 1 is used. 2 uses a borated Mo target,
No. No. 3 using the Fe-Co boride target
A coating layer of a metal boride having the composition described in 1) was formed on the surface of the base material.

Film forming method (2): Test piece No. In Nos. 4 to 6, a boride layer having a higher boron concentration on the surface side was formed by controlling the partial pressure of BCl ₃ gas during film formation using the reactive sputtering method. No. No. 4 uses a Ni target, and No. 4 No. 5 uses a Fe target, and No. 5 6 is N
Using the i-W alloy target, a metal boride coating layer having the composition shown in Table 1 was formed on the surface of the base material.

Film forming method (3): Test piece No. In Nos. 7 to 9, after forming a metal layer by a magnetron sputtering method, a boration treatment was performed in a molten salt at 900 ° C. for 2 hours.
The metal layer formed by the magnetron sputtering method is No. No. 7 is a Cr film, No. 7 8 is Mo film,
No. Reference numeral 9 is an Fe-Ni alloy film, and a metal boride having the composition shown in Table 1 was obtained by performing a boration treatment.

Film forming method (4): Test piece No. 10 to 12 are 9 in molten salt after forming a metal layer by wet electroplating.
Boring treatment was performed at 00 ° C. for 2 hours. The metal layer formed by the wet electroplating is No. 10 is Ni-Cr
Film, No. No. 11 is a Fe-W film, No. 11 12 is Cr-
It was an Fe alloy film and was subjected to a boring treatment to obtain metal borides having the compositions shown in Table 1.

Film-forming method (5): Test piece No. In Nos. 13 to 19, after forming a metal layer by wet electroless plating, a boration treatment was performed in a molten salt at 900 ° C. for 2 hours. The metal layer formed by the wet electroless plating is No. 13 is a Ni film, No. 13 No. 14 is an Fe film, No. 14 15 is Fe-
Ni alloy coating, No. No. 16 is a Co film, No. 16 17 is F
e-Co alloy coating, No. 18 is a Co-Ni alloy film,
No. Reference numeral 19 is an Fe-Co-Ni alloy film, and a boride treatment was performed to obtain a metal boride having the composition shown in Table 1.

Test piece No. Nos. 20 to 23 are comparative examples in which Ti-6Al-4V was used as the base material as in the example, and No. 20 to No. 23 were used. No. 20 is a comparative example in which no surface hardening treatment is applied, No. 20. No. 21 is a comparative example in which the base material is directly subjected to the boring treatment, No. 21. No. 22 is a comparative example in which the base material is directly subjected to the nitriding treatment. Reference numeral 23 is a comparative example in which the base material is plated with Cr.

With respect to the above test pieces, the thickness of the surface-hardened layer was measured by the following method, and the adhesion and wear resistance were examined. <Surface Hardened Layer Thickness> After the boring treatment, cutting and cross-section observation were performed. <Adhesion> It was evaluated by measuring the critical load of a scratch tester. <Abrasion resistance> Using a pin-on-disc type sliding abrasion tester, the pins are nitrided SKD61,
The test was conducted under a load of 1 kg / cm ² . ◎: No wear ○ ○: Abrasion amount less than 10 μm ○: Abrasion amount less than 50 μm ×: Abrasion amount less than 100 μm XX: Abrasion amount 100 μm or more The results are also shown in Table 1.

[0029]

[Table 1]

No. Examples 1 to 19 are examples according to the present invention, and all have excellent adhesiveness and wear resistance. In particular, No. 1 was obtained by forming a metal layer by wet electroless plating and then performing boration treatment. 13 to 19 are very excellent in both properties of adhesion and abrasion resistance. On the other hand, it can be seen that Comparative Examples 20 to 23, which are not surface-treated or are conventionally surface-treated, have poor wear resistance.

Example 2 In the same manner as in Example 1, the test piece No. 1 to 23,
The thickness of the surface-hardened layer was measured, and the melt damage resistance and heat cycle resistance were examined by the following methods. <Melting resistance> 75
Immersion was performed in a molten metal of 0 ° C. and AC8C for 3 hours, and the reduction in the thickness of the film was measured. <Heat-resistant cycle property> Using a heat cycle tester having a high-temperature (650 ° C.) tank and a low-temperature (water-cooled) tank, a cycle of the above-mentioned high-temperature tank and low-temperature tank is repeated for about 2 minutes, and thus a test piece Was subjected to a thermal cycle.
The evaluation was performed by the number of times until the occurrence of cracks on the surface.
The composition of the coating and the evaluation results are also shown in Table 2.

[0032]

[Table 2]

No. 1 to 19 are examples according to the present invention, and in particular, N which was subjected to boration treatment after forming a metal layer.
o. Nos. 7 to 19 are excellent in melting resistance and thermal cycle resistance, and particularly No. 7 in which a metal layer is formed by wet electroless plating. Nos. 13 to 19 are very excellent in both melting resistance and heat cycle resistance. On the other hand, No.
Nos. 20 to 23 are comparative examples according to the conventional method, and are inferior in melting resistance and heat cycle resistance, or at least poor in heat cycle resistance.

[0034]

EFFECTS OF THE INVENTION Since the present invention is constituted as described above, it is possible to form a hard borated layer having excellent adhesion on the surface of a Ti or Ti alloy member, and it is excellent in wear resistance and erosion resistance. It is now possible to provide a Ti or Ti alloy member and a manufacturing method thereof.

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Claims (9)

[Claims] 1. A coating layer made of a metal material having a boron diffusion rate higher than that of the base metal and boron and having a thickness of 10 μm or more is formed on the surface of the base material made of Ti or a Ti alloy. A Ti or Ti alloy member with excellent wear resistance and melting resistance. 2. The metal material constituting the coating layer is F
The T according to claim 1, which is one or more metals selected from the group consisting of e, Co, Ni, Cr, Mo and W.
A member made of i or Ti alloy. 3. The Ti or Ti alloy member according to claim 1 or 2, wherein the content of Fe, Co, and Ni in the metal material forming the coating layer is 90 atomic% or more. 4. The Ti or Ti alloy member according to claim 1, wherein the concentration of boron contained in the coating layer is 1 atomic% or more. 5. The Ti or Ti alloy member according to claim 1, wherein the concentration of boron contained in the coating layer is higher on the surface side of the coating layer than on the base material side. 6. The method for manufacturing a Ti or Ti alloy member according to claim 1, wherein a metal coating layer made of a metal material having a boron diffusion rate higher than that of the base metal is formed on the surface of the base material. A method for producing a Ti or Ti alloy member excellent in wear resistance and melt damage resistance, characterized by diffusing boron into the metal coating layer by performing a boration treatment later. 7. The method according to claim 6, wherein the metal coating layer is formed by a wet plating method or a magnetron sputtering method. 8. The method for manufacturing a Ti or Ti alloy member according to claim 1, wherein the coating layer is formed by a magnetron sputtering method using a target having a composition corresponding to the coating layer. And a method for producing a Ti or Ti alloy member having excellent wear resistance and melting resistance. 9. The method for producing a Ti or Ti alloy member according to claim 1, wherein the metallic material forming the coating layer is used as a target in a boride gas atmosphere by a reactive sputtering method. A method for producing a Ti or Ti alloy member having excellent wear resistance and melt damage resistance, which comprises forming a coating layer.