JPH03100165A - Wear resistant member - Google Patents

Abstract

PURPOSE:To simply and efficiently obtain a wear resistant hard member having superior wear resistance without degenerating the base material by implanting boron ions into the surface of a metal member made of a group IVa, Va or VIa transition metal or an alloy thereof. CONSTITUTION:Boron ions are implanted into the surface of a metal member made of a group IVa, Va or VIa transition metal such as Ti, Zr, V, Nb, Ta, Mo or W or an alloy contg. such metals. This ion implantation can be carried out at a relatively low temp. and the base material is not thermally degenerated. The pref. number of the boron ions implanted is about >=0.5X10<16>, especially about >=1X10<17> per 1cm<2>. A boride coating film formed by the ion implantation has high adhesion, very high hardness and extremely superior wear resistance and can be formed in a short time. A wear resistant member suitable for bearings, engine parts, etc., is obtd.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a wear-resistant member hardened by implanting boron ions into the surface of a transition metal material. It is useful as heat-resistant bearings, wear-resistant sliding equipment members such as automobile engine parts, etc.

[Prior Art] Transition metals belonging to Group 4A, Group SA, and Group 6A of the periodic table (
For example, Ti, Zr, V, Nb, Ta.

Mo, W, etc.) or alloys containing them have a high melting point and excellent high-temperature strength and oxidation resistance, so they have been widely used as structural materials for aircraft, various chemical plants, atomic couplants, etc. However, these transition metals have poor wear resistance compared to steel materials and the like, and are moreover prone to seizure due to friction, so they are hardly ever put to practical use as sliding equipment components.

Therefore, a boron treatment method was developed as a means to overcome these drawbacks and improve wear resistance. This method is
The surface of the transition metal material is boronized by the following method to form a hard boride film. In other words, transition metal borides have: (1) low specific resistance, and (2) hardness of Hv20.
It has the characteristics of being extremely hard (more than 0.00) and extremely stable at high temperatures.By forming this boride on the surface of the transition metal, it not only improves wear resistance but also prevents seizure. This makes it difficult for the material to rise, making it an excellent member for sliding equipment. The following method is known as a method for forming such a surface boride film.

(1) Gas boronization method (boron trichloride method, diborane method) (2) Molten salt method (3) Borax bath method [Problems to be solved by the invention] However, each of the above methods has the following problems. be. First, the above gas boronization method (1) has the disadvantage that it takes a long time to form a hard film of sufficient thickness.
Furthermore, there is a problem that the gas used for surface modification is flammable and toxic, so careful attention must be paid to the maintenance and management of the equipment. Also, (2) above,
(3) Molten salt method and borax bath method also require a long time to form a hard film, and these methods require special surface treatment before and after boriding. ,
The process is extremely complicated. And these (1).

In both methods (2) and (3), the material to be treated is exposed to considerably high temperatures, which may cause thermal deterioration.
It has also been pointed out that the hard coating formed has poor adhesion.

The present invention was made in view of the problems of the prior art, and its purpose is to form a hard film with excellent adhesion without altering the quality of the base material, thereby providing excellent wear resistance. The purpose is to provide a member that shows the characteristics of the material.

[Means for Solving the Problems] The wear-resistant member of the present invention that can solve the above problems is made of a transition metal selected from the group consisting of Group 4A, Group SA, and Group 6A, or an alloy containing them. The gist is that boron ions are implanted into the surface of a metal member.

[Function] In the present invention, a specific transition metal or an alloy thereof as described above is selected as a base material, and its surface is boronized by boron ion implantation.

A feature of boron ion implantation is that it can be performed using a non-thermal process, and a sufficiently thick boride film can be formed even with ion implantation at low temperatures (room temperature), and this film has excellent properties. In addition to exhibiting high temperature stability, it is extremely hard and has excellent wear resistance. Furthermore, this method involves ionizing boron, giving high energy to the ions using an accelerator, and causing them to enter the surface layer of the base material, so the ions are implanted into the base material and create an anchor effect. The adhesion of the boride film is also significantly improved compared to the prior art.

As described above, according to the present invention, since it is a non-heating method, there is no risk of thermal deterioration of the base metal, and a hard film with a considerable thickness can be easily formed in a short treatment time.
Furthermore, the adhesion of the film is good and the physical properties of the film itself are also very good, making it possible to enjoy the advantages of the boriding method while eliminating all the drawbacks pointed out in the conventional method.

As a surface modification method using ion implantation, it is also possible to implant ions other than boron, such as carbon, nitrogen, oxygen, etc. However, the transition metal borides selected in the present invention have much superior properties (especially heat resistance, wear resistance, seizure resistance, etc.) compared to carbides, nitrides, oxides, etc.
Therefore, unless it is a boride film, the heat resistance and abrasion resistance as intended by the present invention cannot be satisfied.

Although the specific conditions for ion implantation are not particularly limited, it has been confirmed through experiments that the implantation amount of boron ions is 1X.
If the amount exceeds 10"ions/cya", the formation of borides can be clearly seen, and the surface becomes hardened accordingly, so it is recommended to set the ion implantation amount to 16 ions/CI2 or more. Good, more preferable is 1
×101 ions/C12 or more. The upper limit of the ion implantation amount may be determined appropriately depending on the target thickness of the implanted layer, the required processing time, the capacity of the ion implantation processing equipment, etc.
The target is up to about 1xio" ion/Cl1l!.

Ion implantation can be performed at room temperature, but if the substrate to be treated is heated appropriately, the diffusion of boron into the substrate during ion implantation will be promoted, making it easier to form boride. It is also advantageous because a relatively thick hardened surface layer can be formed in a shorter treatment time.

Group 4A, Group SA and Group 6 used as substrates of the present invention
A specific example of a group A transition metal is Ti.

Examples include Zr, Hf, V, Nb, Ta, Cr, Mo, and W, and these are appropriately selected and used depending on the purpose. Also, these can be added to 2F if necessary! It is also possible to use a combination of the above or an alloy in combination with metals other than those mentioned above. There are no restrictions on its shape; in addition to the most common plate shape, it may be linear, rod-shaped, or tubular depending on the purpose, or it can be formed into any shape as a base material. Of course, it is also possible to use

[Example] A plate material made of the transition metal shown in Table 1 (25jx25wx
1t) under the conditions shown in the same table to form a boride layer on the surface.

The relative hardness and relative wear amount of each of the obtained ion-implanted materials was investigated using the following method.

Relative hardness: Using a micro Vickers hardness meter, measure the surface hardness under the conditions of an additional load of 10 gf and a holding time of 15 seconds, and calculate the relative hardness with the hardness before ion implantation set as 1.

Relative wear amount: The wear amount is measured using a sliding wear tester using an alumina ball as the mating material, and the relative wear amount is calculated by setting the wear amount before ion implantation to 1.

The results are shown in Table 1, and a surface treated material with high surface hardness and excellent wear resistance was obtained.

Table 1 [Effects of the Invention] The present invention is constructed as described above, and a transition metal material having hard and wear-resistant surface characteristics is subjected to thermal alteration of the base material by boron ion implantation method. Simple JIL
It became possible to manufacture it efficiently using a simple procedure.

Claims (1)

[Claims] (1) Wear resistance characterized by boron ion implantation into the surface of a metal member made of a transition metal selected from the group consisting of Groups 4A, 5A, and 6A or an alloy containing them. Element.