JPH04218669A - Wear resistant ti or ti-base alloy member excellent in lubricity - Google Patents

Abstract

PURPOSE:To offer a technique capable of completing treatment in a short time by a simple process and formable a surface treated layer excellent in adhesion with a Ti base and to offer a Ti or Ti-base alloy member excellent in lubricity and wear resistance obtainable particularly by forming the surface treated layer like the above. CONSTITUTION:In this invention, the constituting gist lies in the point that P ions are implanted into the surface of a Ti or Ti-base alloy member, and a P concn.-enriched layer is formed on the surface layer part of the Ti or Ti-base alloy. By forming the P concn.-enriched layer like the above on the surface layer part, the improve of its strength and the reduction of its friction coefficient can be attained, and the Ti or Ti-base alloy member excellent in lubricity and wear resistance can be realized.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to wear-resistant Ti or Ti-based alloy members with excellent lubricity, and in particular, by improving wear resistance and lubricity, they can be used as sliding machine parts, etc. The present invention relates to a Ti or Ti-based alloy member. In the following explanation, Ti will be taken up as a representative example, but the present invention can be similarly applied to various Ti-based alloys.

0002

[Prior Art] Ti has features such as high melting point, light weight, and high strength, as well as excellent corrosion resistance. Demand for Ti is gradually increasing in fields such as chemical plants and nuclear power plants where these features can be utilized. are doing. However, Ti has the disadvantage that it wears more easily than steel, etc., and has a high coefficient of friction (0.5 to 0.6) especially in the unlubricated state. When Ti is used in parts, the problem of seizure occurs, and this is a cause that prevents the use of Ti as a material for sliding machine parts and the like. Although the coefficient of friction can be lowered by using a lubricant, it cannot withstand long-term use and is not suitable for use as an automobile part, for example.

[0003] Various surface treatment methods have been proposed from the viewpoint of preventing Ti seizure.
Examples of surface treatment methods include: (1) gas nitriding method, (2) Cr plating method, and (2) MoS2 coating method. Although these methods have achieved some success in other fields, they have several problems as a method for treating Ti surfaces. For example, ■Gas nitriding method has the disadvantage of requiring an extremely long processing time, and ■Cr plating method has poor adhesion of the plating film to the Ti substrate, so a pre-treatment step is required to improve the adhesion. It is necessary to perform plating, which makes the process complicated, and there is still a problem that the plating film is likely to peel off. Furthermore ■MoS2
A problem with the coating method is that the adhesion of the surface film is poor, and MoS2 merely functions as a lubricant.

0004

[Problems to be Solved by the Invention] The present invention has been made with attention to these circumstances, and it is an object of the present invention to achieve a process that can be completed in a short time using a simple process, and that has excellent adhesion to the Ti substrate. The purpose of the present invention is to provide a technology that can form a surface treatment layer, and in particular, to provide a Ti member with excellent lubricity and wear resistance that can be obtained by forming such a surface treatment layer. .

[0005]

[Means for Solving the Problems] The Ti member of the present invention which achieves the above object is obtained by implanting P ions into the surface of the Ti (or Ti-based alloy) member, and by implanting P ions into the surface layer of the Ti or Ti-based alloy. The main point is that a P-concentration enriched layer is formed in the P-concentration layer.

[0006]

[Operation] The ion implantation method used in the present invention modifies the surface of a Ti member by implanting accelerated high-energy ions to a target depth, and is used as an impurity doping means in the semiconductor field. In addition, it is being applied to surface modification of metal materials, mainly steel, but so far there has not been much progress in practical application, except in the semiconductor field.

The Ti member according to the present invention utilizes such an ion implantation method to modify the surface of the Ti member, and a non-thermal equilibrium material layer is formed on the surface layer of the Ti member by ion implantation. In other words, in the alloying and surface treatments by thermal processes that have been carried out so far, an alloy layer or surface film that is in a thermal equilibrium state is formed, and since the alloy layer is a thermally equilibrium material layer, there is a natural limit to the modification of its physical properties. was there. In contrast, in the present invention, by forming a non-thermal equilibrium material layer, properties that cannot be predicted from a thermally equilibrium material can be obtained due to stress based on a non-thermal equilibrium state. In other words, even if a Ti alloy containing the same elements as those to be ion-implanted is formed, it cannot be expected to exhibit wear resistance like the Ti member of the present invention.

By the way, in order to improve the characteristics of a Ti member, it is not enough to simply implant ions into the Ti member, but it is necessary to implant ions of a specific element in accordance with the characteristics to be improved. That is, in the present invention, as a result of repeated ion implantation experiments with various elemental ions, in order to improve the seizure resistance of Ti members, P
I learned that I needed to implant ions. Specific changes in the physical properties of the non-thermal equilibrium state formed by implanting P ions into a Ti member include: ■ Increase in surface hardness, ■ Decrease in the coefficient of friction, and ■ Increase in friction with the mating material during wear. The following phenomena can be mentioned: (1) the surface is cleaned by sputtering during ion implantation; (2) the surface oxidation behavior changes during friction;

In addition, in ion implantation, high-energy ions are forcibly added to the surface layer of the Ti member, but since a separate material layer is not formed on the surface layer, the implanted layer and the base material layer have the same matrix structure. It is. Therefore, unlike surface treatments such as plating, where a film made of a different material is adhered to the base material, the ion-implanted surface layer has extremely good integrity with the base material layer, and will not peel off even under frictional conditions. .

The Ti member according to the present invention exhibits the above-mentioned effects, but in order to obtain these effects, it is desirable to implant P ions at a rate of 5×10 15 ions/cm 2 or more. On the other hand, since excessive implantation only increases the processing time and does not improve wear resistance beyond a certain level, it is desirable to suppress the total implantation amount to 1×10 19 ions/cm 2 or less.

[0011]

[Example] Experiment 1 Wear tests were conducted on various ion-implanted Ti members shown in Table 1 using a ball-on-plate wear test device, and the coefficient of dynamic friction and relative amount of wear were compared. The results are shown in Table 1. was gotten. The wear conditions were as follows: alumina, steel, and Ti were used as mating materials, and the test was conducted in air under a load of 1 kgf. The amount of wear was calculated as a relative amount of wear, with the amount of wear of the non-ion-implanted material taken as 1.

0012

[Table 1] Experiment 2 When the ion implantation amount of P was varied, the relationship between the ion implantation amount and the relative wear amount was determined, and the results shown in FIG. 1 were obtained.

As shown in FIG. 1, as the ion implantation amount increases, the relative wear amount decreases, but this tendency becomes noticeable around the point where the ion implantation amount reaches 1×10 16 ions/cm 2 . It was found that the effect was saturated above 1×10 17 ions/cm 2 .

[0014]

[Effects of the Invention] The present invention is configured as described above,
It is possible to obtain a Ti (or Ti-based alloy) member that has excellent lubricity and wear resistance, and exhibits excellent durability against seizure. In this way, it has become possible to apply Ti members with excellent corrosion resistance to applications such as sliding machine parts, which were previously difficult to apply.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between ion implantation amount and relative wear amount.

Claims (1)

[Claims] [Claim 1] A lubricity characterized by implanting P ions into the surface of a Ti or Ti-based alloy member to form a P concentration-enriched layer on the surface layer of the Ti or Ti-based alloy. Excellent wear-resistant Ti or Ti-based alloy member.