JPS62124267A - Wear resistant film, its formation and powdery starting material therefor - Google Patents

Abstract

PURPOSE:To improve the wear resistance of a member by thermally spraying powder contg. Mo (alloy) and TiC on the surface of the member to form a thin film consisting of Mo (alloy) and TiC on the member. CONSTITUTION:A mixture of 95-60pts.wt. Mo (alloy) powder with 5-40pts.wt. TiC powder is thermally sprayed on the surface of a steel substrate with plasma or the like to form a film. This film formed on the steel substrate has satisfactory oil retentivity and remarkably superior wear resistance.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a wear-resistant coating, a method for forming the same, and a raw material powder therefor, and particularly a coating with high oil retention and extremely excellent wear resistance, and a method for forming the same. and raw material powder therefor.

[Prior Art] The constituent materials of mechanical parts and various devices must not only have sufficient mechanical strength but also have characteristics such as wear resistance and corrosion resistance depending on the purpose of use. However, materials with high wear resistance often have low toughness, and it is not easy for one type of material to have two or more properties at the same time.

Therefore, various surface treatment methods have been developed in which the surfaces of components are coated with highly wear-resistant materials.

Such surface treatment methods include plating, waxing,
Various methods are known, such as vapor deposition, thermal spraying, and overlay welding. Among these methods, thermal spraying involves forming a coating on the surface of a component by molten metals, ceramics, etc. and colliding them with a substrate at high speed. For example, by thermally spraying a metal, properties such as corrosion resistance, heat resistance, and conductivity can be improved.

[Problems to be Solved by the Invention] When the surface of a member is thermally sprayed with, for example, a hard metal, the wear resistance is increased accordingly, but when the member is a sliding member that slides on other members, .

The surface becomes excessively smooth due to sliding wear, which may cause seizure. In other words, in the case of a type that supplies lubricating oil to the sliding surface, if one surface is excessively smooth, the oil retention property (oil retention) of the sliding surface will be low, causing oil depletion and seizure. Become.

Furthermore, when ceramic is thermally sprayed, wear resistance can be improved due to the high hardness of the coating, but similarly when the member is a sliding member.

Since the surface of the coating is highly rough, the sliding properties must be low, and the highly hard ceramic coating may damage the mating material.

[Means for Solving the Problems] The wear-resistant coating of the present invention is composed of 11 parts of molybdenum (Mo) or a Mo alloy of 95 to 60 ij and 0 to 40 parts of TiCl.

Further, in the method for forming a wear-resistant coating of the present invention, such a coating is formed by thermally spraying powder containing MO or a Mo alloy and TiC onto the surface of a member.

Furthermore, the raw material powder for forming the wear-resistant film of the present invention is MO
Or it contains 95 to 60 parts by weight of Mo alloy and 5 to 40 parts by weight of TiC.

In the present invention, a mixed film of Mo or a Mo alloy and TiC is used, but the Mo alloy used here includes 50% or less of Fe, 25% or less of A, NilO
% or less, Cr 15% or less, CoIO% or less, and CoIO% or less. In addition, % is weight %. Here, the addition ratio of these alloying elements will be explained.

Fe is cheap and can reduce the price of Mo alloys, but if it is excessively large, it reduces the wear resistance and melting point of Mo alloys, so it is recommended that Fe be added in an amount of 30% or less, especially 20% or less. preferable.

A2 can refine the metal structure and improve its corrosion resistance, but if it is in an excessively large amount, M.

Since it lowers the corrosion resistance and melting point of the alloy, it is preferably added in an amount of 10% or less, particularly 7% or less.

Although Ni is effective in strengthening bases, excessive amounts of Ni tend to generate foreign tissues. Therefore.

The amount of Ni added is preferably 10% or less, especially 7% or less.

Although Cr improves the corrosion resistance of the matrix, it has a strong tendency to form carbides, and if its content is excessively high, the toughness of the metal structure tends to decrease. Therefore, Cr is 15% or less, especially 10%
It is preferable to add the following amount.

Co is effective in strengthening bases, but if it becomes too large, 21tij'I! ! 10 because it lowers the melting point of
It is preferable to set the addition V to less than %, especially less than 7%.

C has the effect of increasing the seizure resistance and wear resistance of the base,
If it increases too much, the amount of carbide precipitation increases and the strength of the base itself decreases, so it should be less than 15%, especially 1.
The amount added is preferably 0% or less.

Note that the raw material powder of the present invention suitable as a thermal spraying raw material for the method of forming a wear-resistant coating of the present invention may be one in which some or all of these additive elements are replaced with Mo, or some with Mo instead of the Mo alloy. It can be used in combination with alloys in powder form,
After these elements are once dissolved, they may be made into a powder state by some method.

The preferred particle size of Mo or Mo alloy in the raw material powder during thermal spraying is 5 to 63 Bm, particularly 5 to 40 gm. Also T
The preferred particle size of iC is 5 to 63 gm, especially 5 to 4
It is 0gm. Moreover, once dissolved, it is preferable that the particle size is 5 to 63 ALm in the form of powder.

In the present invention, Mo
Or what is the mixing ratio of Mo alloy and TiC?

MO or MO alloy 95~6011TUa part, TiC5~
It is 40 parts by weight. When the TiC content exceeds this range, the amount of metal in the coating becomes relatively small, and the toughness of the coating tends to decrease. Further, if the content range of T i C is less than the above range, the abrasion resistance of the coating decreases.

In the method of the present invention, after the powder containing 1MO or Mo alloy and TiC is thermally sprayed onto the surface of the member, the surface of the coating may be further irradiated with a laser beam to promote melting of the coating. This is suitable to be carried out when the raw material powder is insufficiently melted, but even when sufficiently melted powder is sprayed, it has the effect of increasing the density of the sprayed film. Additionally, the heat exchanger also melts the bonding interface between the coating and the substrate, which also has the effect of increasing the bonding strength.

In addition, in the present invention, if the raw material powders are sufficiently melted together and the TiC content is 5 to 13.5 parts, the coating will become a hypoeutectic material and the TiC will be 13.5 to 17.
．． When it is 5 parts by weight, it becomes a eutectic material with a lamellar structure,
If the diameter is 17.5 to 40 tons, it becomes a hypereutectic material.

The method of the present invention can form a film on the surface of almost any material, regardless of the material of the member. Moreover, the thickness of the coating to be formed can be arbitrarily adjusted by changing spraying conditions such as spraying time.

Moreover, such a method of the present invention can be carried out extremely easily by using the raw material powder of the present invention.

C Effect: The wear-resistant coating of the present invention is made of Mo or M, which is a high melting point metal.
This is a cermet coating made of O alloy and TiC, which is a highly hard ceramic. Therefore, it has both the high toughness of Mo or Mo alloy and the heat resistance, high hardness, and chemical stability of TiC.

Such a wear-resistant coating of the present invention is extremely advantageously formed by the method of the present invention, and the raw material powder of the present invention is extremely useful in carrying out the method of the present invention.

In addition, in the method of the present invention, for example, in the coating treated by laser melting immediately after thermal spraying or after thermal spraying,
When the TiC content is between 13.5 and 17.51, the Ml remains in a layered structure consisting of an MO phase or a Mo alloy phase and a TiC phase, as shown in FIG. When the coating surface 1a slides against other members, the layer 2 of the MO phase or Mo alloy phase, which has a lower hardness than TiC, is worn away and the TiC phase 3 protrudes from the coating surface, as shown in FIG. A large number of minute recesses 6 are formed on the exposed surface of the film. This concave portion 6 acts as a good oil reservoir, and the lubricating oil retention property is significantly increased, and the wear resistance of the surface of one member is significantly improved.

In FIGS. 1 and 2, reference numeral 4 indicates one grain constituting the coating, and reference numeral 5 indicates the main body side of the member.

[Example] Example 1 Mo powder and TiC powder were mixed and plasma sprayed to form a coating on the surface of an FTF4 substrate having a size of 10 cm x IO cm according to the method of the present invention.

The particle sizes of the Mo powder and TiC powder used and the thermal spraying conditions are as shown below.

Blend amount Mo: 84, 5-fold 1 part TtC: 15, 5-fold particle size Mo powder: 1Opm to 63am TiC powder: 10gm to 54mm Spraying conditions Thermal spraying film 21: Plasma spraying equipment powder supply ff : 2 kg/hr example? A film made of Mo alloy and TIC was formed on the surface of the substrate in the same manner as in Example 1 except that Mo alloy was used instead of MO and the mixing ratio of T i C was changed. In addition, M
The composition of the o alloy is as shown below.

Mo: 70% Fe: 15% CO: 5% Ni: 5% A: 3% C: 2% Further, the mixing ratio of TiC powder was 10 parts by weight.

Example 3 The same operations as in Example 2 were carried out except that the mixing ratio of Mo alloy and T i C was 70 + 30 and that the laser beam was irradiated one more time after the thermal spray coating was formed. A film was formed on the surface of the substrate.

Note that the laser irradiation conditions are as follows.

Model of laser device: CO2 laser output +4 kW Scanning speed +0.4 m/sec Test Example 1 The sliding characteristics of the members having the coatings obtained in Examples 1 to 3 were evaluated using a Binion disc type wear test material. I checked.

The test piece is a pin type test piece and a disc type test piece.
Each was produced by forming a film by the method of Examples 1 to 3. Using each test piece, the same coatings were slid against each other and the amount of wear was investigated.
It was found that the coating formed in No. 3 had extremely excellent wear resistance.

An example of the test results is shown in Figure 3. Figure 3 shows the amount of wear and tear when the test was conducted using a coating made of Mo-22,5% TiC sprayed material formed by the method of Example 1. The relationship with load is shown together with the results when flaky graphite cast iron materials are used. The test temperature in this case is 180
℃, the sliding speed was 1.8 m/sec, and engine oil (SAE #20) was used as the lubricant.

It is clear from FIG. 3 that the coating formed according to the method of the present invention exhibits an order of magnitude less wear than cast iron.

[Effects] As detailed above, the wear-resistant coating of the present invention has good oil retention and is extremely excellent in wear resistance.

Such a film can be formed extremely easily by the method of the present invention and by using the raw material powder of the present invention.

According to the present invention, it is possible to significantly extend the durability of sliding members and the like that use lubricating oil.

[Brief explanation of drawings]

FIGS. 1 and 2 are schematic cross-sectional views showing the structure of a coating formed by the method of the present invention. FIG. 3 is a graph showing the results of the wear test of Test Example 1. DESCRIPTION OF SYMBOLS 1... Coating, 2... Mo phase or MO-associated metal phase, 3... T i C phase, 4... One grain constituting the coating, 5...
...No, (board, 6...4 parts. Agent Patent attorney Tsuyoshi Tamano 1 Figure s 2
Figure s 3 Figure Shundong (let /c-)

Claims (3)

[Claims] (1) A wear-resistant coating comprising 95 to 60 parts by weight of molybdenum or a molybdenum alloy and 5 to 40 parts by weight of TiC. (2) A powder containing molybdenum or a molybdenum alloy and TiC is thermally sprayed onto the surface of the member, and 95 to 60 parts by weight of molybdenum or a molybdenum alloy and 5 to 4 parts by weight of TiC are applied to the surface of the member.
1. A method for forming a wear-resistant coating, comprising the step of forming a coating consisting of 0 parts by weight. (3) A raw material powder for forming a wear-resistant coating, characterized by comprising a powder containing 95 to 60 parts by weight of molybdenum or a molybdenum alloy and 5 to 40 parts by weight of TiC.