JPH02138402A - Metal-coated metallic sulfide powder and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve adhesion and uniform stickness of coating by using powder of Zn, Sn, Pb, etc., coating the surface of metallic sulfide powder with above powder and successively applying Cu, Ni, Co, etc., with chemical plating. CONSTITUTION:The metallic sulfide powder of MoS2, etc., and metal powder selected among Zn, Sn, Pb or solder, etc., are charged into a vessel and heated at higher temp. than liquid-phase generating temp. of the metal powder and stirred. By this treatment, the surface of the metallic sulfide powder is coated with inner layer selected among Zn, Sn, Pb or solder, etc. Successively, the surface of the inner layer is coated with outer layer selected among Cu, Ni, Co, etc., with the chemical plating. By this method, the double coated metallic sulfide powder having large adhesive strength is obtd. with heat treatment at a comparatively low temp.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a metal-coated metal sulfide powder and a method for producing the same. More specifically, the present invention provides a novel metal-coated metal sulfide powder with excellent adhesion strength and uniform coating properties, which prevents the metal sulfide powder from being consumed during processes such as sintering and thermal spraying, and this metal-coated metal sulfide powder. The present invention relates to a method for producing metal-coated metal sulfide powder that can stably, reliably, and economically obtain coated metal sulfide powder.

The metal-coated metal sulfide powder according to the present invention can be used for oil-impregnated bearings,
It can be applied to carbon brushes, friction materials, thermal spray materials, etc.

[Conventional technology and its issues]

Since metal sulfide powder has self-lubricating properties, copper powder,
After being mixed with silver powder or the like, a bearing is formed into a shape by powder metallurgy or thermal spraying.

However, the metal sulfide powder used here, especially molybdenum disulfide powder, which is a typical example, cannot be mixed with copper powder, etc. due to differences in apparent density and surface condition, making it difficult to obtain a uniform mixed powder. Moreover, it has drawbacks such as being consumed during sintering or thermal spraying. For this reason, metal sulfide powder coated with a metal such as copper or nickel on the surface has conventionally been used.

The second metal coating is required to have uniform coating properties and adhesion strength that will not peel off during mixing or thermal spraying.

Conventionally, methods for coating non-metallic powders such as molybdenum disulfide powder with copper, nickel, etc. include the cementation method using ion replacement, the method of metal precipitation using hydrogen etc. under high temperature and high pressure, or the method of coating copper, nickel, etc. on non-metallic powder such as molybdenum disulfide powder. A method is known in which electroless plating is performed using cementation on an activated inorganic powder.

For example, as a method for coating metal sulfide powder with copper,
A method using a cementation reaction in which an acidic solution containing copper ions is added to a mixture of a metal baser than copper and a metal sulfide powder (Japanese Patent Publication No. 57-31532.58-322)
01) is known. However, metal sulfide powder whose surface is difficult to activate has the disadvantage that it is difficult to uniformly coat the copper layer and the adhesion strength is low.

In order to improve the above-mentioned drawbacks, a method of pre-activating metal sulfide powder is to coat the surface of the metal sulfide powder with a platinum group coating layer by thermal decomposition of a platinum group compound, and then apply a cementation reaction to the surface. How to coat copper using
Special Publication No. 57-31533) has been proposed. but,
This method is also essentially a substitution reaction between a base metal and copper,
When coating metal sulfide powder, there are problems with uniform coating and adhesion.

In addition, immersion treatment is performed with palladium chloride as the active side,
Calcium fluoride as a core in an ammoniacal solution,
A method of coating cobalt, nickel, etc. in reducing gas at high temperature and high pressure has been proposed (Japanese Patent Publication No. 55-1321).

However, this method requires only 2 g/f of expensive white metal! It is necessary to add more than 100% of the total amount of hydrogen, which increases the processing cost, and the hydrogen reduction reaction is carried out at high temperature and high pressure, which is not industrially practical.

Furthermore, in order to solve these problems, a method has been proposed in which metal sulfide powder is subjected to immersion activation treatment in an aqueous solution of ferrous sulfate, stannous chloride, and silver nitrate (Japanese Patent Publication No. 6O-255902). However, this method has disadvantages in that the treatment is complicated and the control of the treatment liquid is difficult, and the hydrogen reduction reaction is carried out under high temperature and pressure, similar to the method of Japanese Patent Publication No. 55-1321 mentioned above.

[Means to solve the problem]

The inventor of the present invention has solved the various problems of the various conventional techniques mentioned above (as a result of various researches), and has finally completed the present invention which can achieve the intended purpose.

There are two types of metal-coated metal sulfide powder according to the present invention, in which the coating layer formed on the surface of the metal sulfide powder is an inner layer selected from a zinc layer, a tin layer, a lead layer, or a solder layer; This type consists of an outer layer selected from a copper layer, a nickel layer, or a cobalt layer (hereinafter referred to as a "double coating layer type"). It is an alloyed type (hereinafter referred to as "diffusion/alloy strengthened type"). The latter is obtained by heat-treating the former, and maintains the distinction between the inner and outer layers depending on the type of metal in the inner or outer layer and the heat treatment conditions (hereinafter referred to as "diffusion/alloy reinforced type"). ), and those that do not maintain the distinction between the inner and outer layers (hereinafter referred to as "diffusion/alloy type strengthening type 2").
It can be divided into Diffusion/alloy type reinforcement type 1 is characterized by the fact that the metal of the inner layer and the metal of the outer layer that make up the coating layer are mutually diffused or alloyed at the interface between the inner layer and the outer layer. It is.Also 1,
Diffusion/alloy type reinforcement type 2 is a further progress in diffusion or alloying of diffusion/alloy type reinforcement type 1, and the coating layer formed on the surface of the metal is selected from zinc, tin, lead, or solder. It is characterized by being a mutually diffused product or alloy of a metal selected from copper, nickel, or cobalt.

Next, a method for producing metal-coated metal sulfide powder according to the present invention will be explained.

The method for producing a double coating layer type metal-coated metal sulfide powder according to the present invention includes charging a metal sulfide powder and a metal powder selected from zinc powder, silver powder, lead powder, or solder powder into a container;
The surface of the metal sulfide powder is coated with an inner layer selected from a zinc layer, a tin layer, a lead layer, or a solder layer by heating and stirring the metal powder to a temperature higher than the liquid phase generation temperature, and then the surface of the inner layer is coated with a chemical. It is characterized by coating with an outer layer selected from a copper layer, a nickel layer, or a cobalt layer by plating to obtain a metal-coated metal sulfide powder in which the surface of the metal sulfide powder is double coated with an inner layer and an outer layer. It is something.

Further, the method for producing a diffusion/alloy type reinforced metal-coated metal sulfide powder according to the present invention includes heating the metal-coated metal sulfide powder obtained by the above-described method in a reducing atmosphere or an inert atmosphere at 250 to 700°C. By heating at
Diffusion/alloy type strengthening type] or diffusion/alloy type strengthening type 2 is obtained.

Next, the configuration of the present invention will be explained in detail.

What is the metal sulfide powder in the present invention? Typical examples include molybdenum disulfide and tungsten disulfide.

The solder referred to in the present invention is a soft solder defined by ISO, such as tin-lead, tin-zinc, tin-antimony, tin-antimony, and lead-tin.
Unfortunately, it is a zinc-silver alloy.

Zinc, tin, lead or solder is 1% per metal sulfide powder.
It is preferable to coat with ~50 wtχ. This is 1wt
% or less, uniform coating cannot be achieved, and even if the coating exceeds 50 w tχ, no improvement in properties is observed.

The metal-coated metal sulfide powder according to the present invention has zinc, tin, lead, or solder on the surface of the metal sulfide powder, so these react with sulfur in the metal sulfide, and zinc, tin,
Forms sulfides with lead (including lead in solder). Therefore, the adhesion strength between zinc, tin, lead or solder and the metal sulfide is improved compared to platinum group metals which have less reactivity with the metal sulfide.

In addition, since the price is lower than that of platinum group metals, a large amount of metal can be coated, and therefore the coating can be made more uniform. moreover,
Zinc, tin, lead or solder is copper.

It has good plating coverage even with nickel or cobalt, and has high adhesion strength.

Next, a method for producing a double coating layer type metal-coated metal sulfide powder according to the present invention will be explained. The process is roughly divided into a process of coating an inner layer selected from the layers, and a process of coating the outer layer selected from a copper layer, nickel NH, or cobalt layer thereon.

Vapor phase plating or melt plating can be applied to coat the surface of metal sulfide powder with an outer layer, but manufacturing costs and
Hot-dip plating is preferred from the viewpoint of coating uniformity and adhesion strength. The specific method of hot-dip plating is as follows. A metal sulfide powder and a metal powder selected from zinc powder, silver powder, lead powder, or solder powder to achieve a predetermined coating amount are charged into a closed rotary drum. At this time, if up to 20% by weight of flux such as ammonium chloride is added at the same time, the wettability between the metal powder and the metal sulfide powder will improve, making plating easier. Furthermore, if beads such as glass beads and stainless steel beads are added at the same time, the kneading properties of the metal powder and metal sulfide powder will improve, making plating easier. While rotating the rotating drum, heat the metal powder using a gas burner etc. at a temperature higher than the temperature at which the liquid phase occurs.
Heat for 60 minutes. Since hot-dip plating is impossible below the liquid phase generation temperature of the introduced metal powder, it is necessary to heat the metal powder above this temperature. When this heating is performed in air, the temperature must be 450° C. or lower to prevent decomposition of the metal sulfide. On the other hand, when heating in a reducing atmosphere or an inert atmosphere, the metal sulfide does not decompose even at 450° C. or higher, so treatment at higher temperatures is also possible. After the heat treatment is completed, it is cooled, and then the metal sulfide powder coated with the inner layer is separated from the beads and taken out.

Moreover, by performing this hot-dip plating, even if the particle size of the metal sulfide powder is small, the coated metal acts as a binder, so the metal sulfide powder is granulated or sized.

By using the metal sulfide powder coated with the inner layer thus obtained, a uniform outer layer can be obtained with high plating efficiency.

Next, a copper layer on the surface of the metal sulfide powder coated with an inner layer,
To coat the outer layer selected from the nickel layer and cobal +-i, other methods such as displacement plating, electroplating, vapor phase plating, etc. can be applied in addition to chemical plating, but chemical plating is preferred from the viewpoint of stability. The processing conditions for chemical plating vary depending on the type of metal used, so they will be explained for each metal.

When coating copper, the metal coated with the inner layer is added to a solution of a complexing agent capable of forming a chelate bond with copper, such as Rossel's salt, citric acid, or ethylenediaminetetraacetic acid adjusted to pH 10 to 13. Add sulfide powder. Next, by gradually dropping a formalin solution and an aqueous copper compound solution while stirring and maintaining the pH above, copper can be plated. The reaction temperature is 15-40"C in the case of Rosselle's salt bath, 25-45"C in the case of citrate bath, 2 degrees Celsius in the case of ethylenediaminetetraacetic acid bath.
The temperature is preferably 5 to 60°C. If the temperature exceeds the above upper limit, the plating bath is likely to decompose, and abnormally precipitated copper powder will be present in the metal-coated metal sulfide powder, which may deteriorate the quality of the product. On the other hand, if the temperature does not reach the lower limit mentioned above,
Plating reaction is difficult to proceed.

When coating with nickel, the metal sulfide powder coated with the inner layer is placed in an alkaline solution of Rosselle's salt or citrate adjusted to pH 8-13.

Next, while stirring and maintaining the above pH, a reducing agent selected from sodium hypophosphite, hydrazine, or borohydride and an aqueous di-Sikel compound solution are gradually added dropwise to remove nickel. You can. The reaction temperature is preferably 60 to 95°C.

When coating with cobalt, the same operation as for nickel coating can be performed except that the pH is maintained at 11 to 13 and an aqueous cobalt compound solution is used as the metal source.

According to the above chemical plating method, almost the entire amount of the injected metal is plated on the surface of the inner layer, and the desired outer layer can be easily formed with precision, and bath management is very easy. It has the characteristic of being wet.

Incidentally, after completing the above-mentioned plating, washing with water and drying are performed to obtain a double coating layer type metal-coated metal sulfide powder according to the present invention.

The double coating layer type metal-coated metal sulfide powder obtained by the method described above has good uniform coating properties and good adhesion. However, depending on the field of use, even stronger adhesion may be desired. For example, when used for sintered metals, it is necessary to prevent the coating layer from peeling off when mixed with dissimilar metal powder such as copper powder. A metal-coated metal sulfide powder that satisfies such characteristics is a diffusion/alloy type reinforced type powder according to the present invention. The manufacturing method will be explained below. The double layer type metal-coated metal sulfide powder obtained by the method described above may be heated in a reducing atmosphere such as hydrogen or ammonia decomposition gas, or in an inert atmosphere such as nitrogen, argon, helium, etc. Heating conditions are 250-700″C for 10
Heat treatment may be performed for a minute to several hours. Heat treatment at 250”C
If it is below, diffusion or alloying or softening of the outer layer will not proceed sufficiently, so it will tend to be difficult to improve adhesion. On the other hand, if the temperature is 700° C. or higher, sintering of the metal-coated metal sulfide powder itself tends to occur, and when the sintered powder is processed in a pulverizer, the coating layer is crushed and the metal sulfide is exposed.

When the double coating layer type metal-coated metal sulfide powder is heat-treated at a predetermined temperature in this manner, the reaction between the metal sulfide and the zinc, tin, lead, or solder constituting the inner layer becomes active. Furthermore, at the same time, the inner layer and the outer layer shrink due to sintering. During this sintering, mutual diffusion or alloying between the metal of the inner layer and the metal of the outer layer progresses. It is presumed that this occurs because the metal precipitated particles by hot-dip plating and the coated metal precipitated particles by chemical plating are extremely fine, dense, and highly active. Whether diffusion or alloying occurs is determined by the heat treatment conditions of the double layer type metal-coated metal sulfide powder. Further, in the case of a combination of an inner layer metal and an outer layer metal (for example, the inner layer is lead and the outer layer is copper), mutual diffusion or alloying may be difficult to occur.

However, in this case as well, by performing the above heat treatment, the strain in the outer layer caused by chemical plating is removed and softened, and as a result, the outer layer can be stabilized. By the way, the above-mentioned mutual diffusion or alloying of the metal of the inner layer and the metal of the outer layer can be achieved by diffusion/alloy reinforcement type 1, which maintains the separation between the inner layer and the outer layer, depending on the type of metal of the inner layer or outer layer and the heat treatment conditions. In other cases, it becomes diffusion/alloy type reinforcement type 2, which does not maintain the distinction between the inner and outer layers.

The diffusion/alloy-type reinforced metal-coated metal sulfide powder according to the present invention thus obtained shows almost no peeling of the copper, nickel or cobalt layer even when mixed with different metal powder. Become.

〔Example〕

Next, the configuration of the present invention will be explained based on examples.

Example 1 In a closed rotary drum (500 mft capacity), 20 g of commercially available molybdenum disulfide powder (manufactured by Sumiko Lubricants ■, trade name "Moly Powder"), 1 g of solder (tin 63%-lead) powder, and commercially available 1 grade ammonium chloride 1g, glass beads (diameter 2mm)
) and heat-treated at 190''C for 30 minutes with a gas burner while rotating the drum to obtain molybdenum disulfide powder whose surface was coated with a solder (tin-lead) layer.

Next, after sieving this powder, pH 12,0-1
Rossel salt adjusted to 2.5 (150g/f) 20
Plating was performed by dropping a plating solution containing a cupric chloride solution (20 g of copper, 10% solution) and a 35% formalin solution while stirring and maintaining the above pH. After filtering and drying, the solder (tin-
40 g of copper-solder (tin-lead) coated molybdenum disulfide powder was obtained, the surface of which was coated with a copper layer.

The copper ion concentration in the solution after the reaction is 0.02P P m
Approximately 100% of the implanted copper ions are plated,
The color tone and coverage were also perfect.

Example 2 20 g of the copper-solder (tin-lead) coated molybdenum disulfide powder obtained in Example 1 was heated at 350°C for 2 hours in a hydrogen gas atmosphere.
A time heat treatment was performed to obtain a copper-tin-lead alloy coated molybdenum disulfide powder in which the copper forming the outer layer and the solder (tin-lead) forming the inner layer were alloyed.

Example 3 Into the closed rotary drum used in Example 1, 20 g of commercially available molybdenum disulfide powder (manufactured by AMAX, trade name "Technical Grade") and solder (92% tin-zinc) powder (250 mesh under) were added. 2g, commercially available primary ammonium chloride 2g
, add 8g of glass peas (Fill 2mm),
Heated at 210'C for 40 minutes with a gas burner.
The surface of molybdenum disulfide powder is semi-ETI (tin zinc) N
A powder coated with was obtained.

Next, add copper sulfate (copper 22
g, 10% solution) and formalin, and 2Na-ethylenediaminetetraacetic acid (2Na-ethylenediaminetetraacetic acid) was used as a complexing agent.
Chemical plating was performed in the same manner as in Example 1 using 150 g/l) and 200 mA. As a result, the solder described above (
Copper-solder (tin-zinc) H coated with a copper layer
44 g of copper-coated molybdenum disulfide powder was obtained.

Example 4 20 g of the copper-solder (tin-zinc) coated molybdenum disulfide powder obtained in Example 3 was added to 70 Volx of hydrogen gas.

Heat treated at 400''C for 30 minutes in an atmosphere of nitrogen gas 30 Volχ to form a copper-tin-zinc alloy coated disulfide alloy in which the copper forming the outer layer and the solder (tin-lead) forming the inner layer were alloyed. Molybdenum powder was obtained.

Example 5 In the closed rotary drum used in Example 1, molybdenum disulfide powder (manufactured by Sumiko Lubricants ■: trade name "Moly Powder") was placed.
20g, 0.6g of silver powder, and 5g of glass peas were heated at 230°C for 30 minutes using a gas burner.
A powder was obtained in which the surface of molybdenum disulfide powder was coated with a tin layer.

Next, the surface of this powder was chemically plated in the same manner as in Example 1 so that the copper coating amount was 60%, and the copper-tin-coated disulfide powder was coated with a copper layer on the surface of the tin layer. 51 g of molybdenum powder was obtained.

Example 6 20 g of the copper-tin-coated molybdenum disulfide powder obtained in Example 5 was heat-treated at 500°C for 30 minutes in argon gas to form an alloy between the copper forming the outer layer and the tin forming the inner layer. A copper-tin alloy coated molybdenum disulfide powder was obtained.

Example 7 In the closed rotary drum used in Example 1, molybdenum disulfide powder (manufactured by Sumiko Lubricants ■: trade name "Moly Powder") was added.
Add 20g of zinc powder and 15g of zinc powder and 20g of glass peas.
Heat treatment was performed at 430°C for 30 minutes using a gas burner.
A powder was obtained in which the surface of molybdenum disulfide powder was coated with a zinc layer.

Next, chemical plating was performed on the surface of this powder in the same manner as in Example 1 so that the amount of copper coating was 50%, and the surface of the above-mentioned zinc layer was coated with a W4 layer. 70 g of molybdenum powder was obtained.

Example 8 20 g of the copper-zinc coated molybdenum disulfide powder obtained in Example 7 was heat-treated in hydrogen gas at 550°C for 1 hour to form an alloy between the copper forming the outer layer and the zinc forming the inner layer. A copper-zinc alloy coated molybdenum disulfide powder was obtained.

Comparative Example 1 Molybdenum disulfide powder (manufactured by Sumiko Lubricants ■: product name [Moly Powder J,
Add 200 mff1 of palladium nitrate aqueous solution (palladium 0.1 g/f solution) to 200 g (average particle size 15 μ), mix, dry with an infrared lamp, dehydrate, and dry with a gas burner for 30 minutes.
Heat treatment was performed at 50°C for 30 minutes. Next, this and 180 g of reduced iron powder with a particle size of 200 mesh under were placed in a cementation container equipped with a stirrer, and while mixing, an acidic copper sulfate solution (free acid 200 g/f) was added.

50g/14j2 of copper was gradually added and the cementation reaction was carried out for 15 minutes. The amount of copper precipitation after washing with water and drying is 49%
Met. In this way, a copper-palladium-coated molybdenum disulfide powder was obtained, in which the surface of the molybdenum disulfide powder was coated with a palladium layer as an inner layer and a copper layer as an outer layer.

Table 1 shows the peel test results of the coating layer of the metal-coated molybdenum disulfide powder obtained in Examples 1 to 8 and Comparative Example 1 and the structure XMA of the coating layer.

Mugijo*1: The ratio of completely covered powder to the whole was randomly sampled from 5 visual fields by observation using a stereomicroscope (250x magnification), and the average value was determined.

*2: The metal-coated molybdenum disulfide powders obtained in Examples 1 to 8 and Comparative Example 1 were targeted.

*3: The metal-coated molybdenum disulfide powder obtained in Examples 1 to 8 and Comparative Example 1 (70 vol.

*4: Surface composition was analyzed using an X-ray microanalyzer.

Example 9 In a closed rotary drum (500 + + + j! capacity), 20 g of commercially available molybdenum disulfide powder (manufactured by AMAX: trade name "Technical Fine", average particle size 0.8 μ), 2 g of silver powder, commercially available primary ammonium chloride Ig, Glass peas (diameter 2
mm) 5g was added at the same time and heated at 250"C for 1 hour with a gas burner while rotating the drum.
A powder was obtained in which the surface of molybdenum disulfide powder was coated with a tin layer.

Next, after sieving this powder, pH 12,0-1
Rossel salt adjusted to 2.5 (150g/1) 20
0m: Added during the night, and while stirring, the above pH
Cupric chloride solution (51 g as copper, 10
% solution) and formalin 35% solution at a temperature of 20 to 2
Plating was performed by dropping a plating solution adjusted to 5°C.

After filtering and drying, 72 g of copper-tin-coated molybdenum disulfide powder was obtained, in which the surface of the tin layer was coated with a copper layer.

The copper ion concentration in the solution after the reaction is 0.02 p p m
Approximately 100% of the implanted copper and ions were plated, and the color tone and throwing power were perfect.

Example 10 20 g of the copper-tin coated molybdenum disulfide powder obtained in Example 9 was heat-treated at 400'C for 1 hour in a hydrogen gas atmosphere, so that the copper forming the outer layer and the tin forming the inner layer were separated. An alloyed reinforced copper-tin coated molybdenum disulfide powder was obtained.

Example 11 In the closed rotary drum used in Example 9, 20 g of commercially available molybdenum disulfide powder (manufactured by Sumiko Lubricants ■: trade name "Molypowder PBJ average particle size 15 μm") and solder (63% tin - lead) were added. ) powder, 2 g of commercially available primary ammonium chloride + 7 g of glass peas (diameter 2 mm), and heated with a gas burner.
Heating was performed at 90° C. for 240 minutes to obtain molybdenum disulfide powder whose surface was coated with solder (tin-lead).

Next, a solution containing a cupric chloride solution (21 g of copper, 10% solution) and a formalin solution was used as a plating solution so that the copper coating amount was 50%, and a pH
Using 250 ml of 2Na-ethylenediaminetetraacetic acid (150 g/l) adjusted to 12.0 to 12.5,
Chemical plating was performed in the same manner as in Example 9 at a reaction temperature of 50°C.

As a result, 42 g of copper-solder (tin-lead) coated molybdenum disulfide powder was obtained, in which the surface of the solder (tin-lead) layer described above was coated with a copper layer.

Example 12 20 g of copper-solder (tin-lead) coated molybdenum disulfide powder obtained in Example 11 was heated at 250° C.93 in a hydrogen gas atmosphere.
Heat treatment is performed for 0 minutes, and the outer copper layer and inner solder layer (tin-
A strengthened copper-tin-lead coated molybdenum disulfide powder was obtained in which copper and solder (tin-lead) were alloyed at the interface with lead).

Example 13 In the closed rotating drum used in Example 9, 20 g of molybdenum disulfide powder (manufactured by AM^X: "Technical grade" average particle size 7 μm) and 0.6 g of solder (tin 92% zinc) powder were placed.
g, put 5g of glass pieces and burn it on a gas burner for 21 hours.
Heat treatment was performed at 0° C. for 230 minutes to obtain molybdenum disulfide powder whose surface was coated with a solder (tin-zinc) layer.

Next, chemical plating was performed on the surface of this powder in the same manner as in Example 9 so that the copper coating amount was 60%, and copper-solder (tin-solder) was coated with a copper layer on the surface of the solder layer described above. 52 g of zinc-coated molybdenum disulfide powder was obtained.

Example 14 20 g of the copper-solder (tin-zinc) coated molybdenum disulfide powder obtained in Example 13 was added to 70 vol x of hydrogen gas.

Heat treatment was performed at 350°C for 1.5 hours in a nitrogen 30vo Iχ atmosphere to form a strengthened copper-tin-zinc coated two in which the copper forming the outer layer and the solder (tin-zinc) forming the inner layer were alloyed. Molybdenum sulfide powder was obtained.

Example 15 In the closed rotating drum used in Example 9, 20 g of molybdenum disulfide powder (Moly powder P[l) and solder (tin 93
．． 1 g of 5%-silver) powder and 10 g of glass peas were added and heat-treated at 230°C for 1 hour using a gas burner to obtain a powder in which the surface of the molybdenum disulfide powder was covered with a solder (tin-silver) layer. Ta.

Next, after sieving this powder, the pH was adjusted to 11-11°5.
Rossel salt (100g/l) adjusted to 200mf
Add 21 g of nickel to the nickel chloride solution (10χ solution) and sodium hypophosphite solution (10χ solution) and adjust the reaction temperature to 80 to 85°C while stirring and maintaining the above pH. Plating was performed by dropping the plating solution. After filtering and drying, the solder described above (
42 g of molybdenum disulfide powder coated with nickel solder (tin-silver) was obtained, in which the surface of the tin-silver layer was coated with a nickel layer.

Example 16 20 g of the nickel-solder coated molybdenum disulfide powder obtained in Example 15 was heat-treated at 450'C in argon gas for 1 hour to separate the nickel forming the outer layer and the solder (tin-silver forming the inner layer). ) was obtained. A reinforced type nickel-tin-silver coated molybdenum disulfide powder was obtained.

Example 17 20 g of molybdenum disulfide powder (AMAX technical grade), 10 g of zinc powder, and 10 g of glass peas were placed in the closed rotating drum used in Example 9, and heat treated with a gas burner at 430"C for 30 minutes. A powder in which the surface of molybdenum disulfide powder was coated with a zinc layer was obtained.

Next, a nickel sulfate and hydrazine solution was dropped onto the surface of this powder so that the amount of nickel coated was 60χ, and the pH was adjusted to 8.
~8.5. Plating was carried out in the same manner as in Example 9 at a temperature of 90 to 95°C. As a complexing agent, 200 ml of sodium citrate solution (150 g/I!) was used. 75 g of nickel-zinc coated molybdenum disulfide powder was obtained, in which the surface of the zinc layer was coated with a nickel layer.

Example 18 20 g of the nickel-zinc coated molybdenum disulfide powder obtained in Example I7 was heat-treated at 350'C in nitrogen gas for 30 minutes to form an alloy between copper and zinc at the interface between the outer nickel layer and the inner zinc layer. A reinforced nickel-zinc coated molybdenum disulfide powder was obtained.

Example 19 Into the closed rotary drum used in Example 9, 20 g of molybdenum disulfide powder (technical), 1512 g of lead + stainless steel beads (diameter i, 5 mm) log were put, and heated at 330"C for 45 minutes with a gas burner. Perform heat treatment,
A powder was obtained in which the surface of molybdenum disulfide powder was coated with a lead layer.

Next, cobalt sulfate (33g of cobalt, 10χ solution) and sodium hypophosphite (10χ solution) were used as the plating solution so that the cobalt coating was 60χ, and sodium citrate (150i,!) was used as the complexing agent. , p Hl
Cobalt plating was carried out in the same manner as in Example 9 while adjusting the reaction temperature to 85 to 90°C.

As a result, 55 g of cobalt-lead coated molybdenum disulfide powder was obtained, in which the surface of the lead layer was uniformly coated with a cobalt layer.

Example 20 20 g of the cobalt-lead coated molybdenum sulfide powder obtained in Example 19 was heat-treated in water injection gas at 550''C for 1.5 hours to form a reinforced cobalt-lead coat with a softened outer cobalt layer. Molybdenum disulfide powder was obtained.

Comparative Example 2 Molybdenum disulfide powder (manufactured by AMAX = "Technical Fine.

200 mR of palladium nitrate aqueous solution (palladium 0.15 g #! solution) was added to 200 g of 0.8 µm (average particle size) and mixed, dried and dehydrated with an infrared lamp, and then heated with a gas burner at 350° C. for 130 minutes. Next, this and 420 g of reduced iron powder with a particle size of 200 mesh under were placed in a cementation container equipped with a stirrer, and while mixing, an acidic copper sulfate solution ('t1 200 g/j2, copper 50
g/f) 9.44! was gradually added and the cementation reaction was carried out for 15 minutes. The amount of copper precipitated after the reaction is 69%
However, a uniform coated powder could not be obtained, and a mixed powder of molybdenum disulfide and copper powder was present in some parts.

Comparative Example 3 Molybdenum disulfide powder with a large particle size (manufactured by AM^X: XLP-) was placed in an open rotating drum (1000 mff capacity).
1. Add palladium nitrate aqueous solution (palladium 0.15 g/ffi solution > 20
0d was added and mixed 7, and after drying and dehydration using an infrared lamp, heat treatment was performed at 350°C for 130 minutes using a gas burner. Next, this and reduced iron powder 42 with a particle size of 200 mesh under
0g of copper was added to a cementation container equipped with a stirrer, and while mixing, an acidic copper sulfate solution (20h/l of free acid, 50g of copper, 719.4f of copper) was gradually added, and a cementation reaction was performed for 15 minutes. Washed with water and dried. The amount of copper precipitation after is 49%
Met. In this way, Ii-palladium-coated molybdenum disulfide powder was obtained, in which the surface of the molybdenum disulfide powder was coated with a palladium layer as an inner layer and a copper layer as an outer layer.

Table 2 shows the peel test results of the coating layer of the metal-coated molybdenum disulfide powder obtained in Examples 9 to 20 and Comparative Example 2.3 and the structure XMA of the coating layer.

Table 2 *1: By observation using a stereomicroscope (250x magnification), the percentage of completely covered powder in the total was randomly sampled from 5 fields, and the average value was determined.

*2: The metal-coated molybdenum disulfide powders obtained in Examples 9 to 20 and Comparative Examples 2 and 3 were targeted.

*3: The metal-coated molybdenum disulfide powder obtained in Examples 9 to 20 and Comparative Example 2.3, 70 vol.chi., was rotary mixed for 1 hour with 30 vol.

*4: Surface composition was analyzed using an X-ray microanalyzer.

*5: More than 60% of the mixture of palladium-coated molybdenum disulfide and copper powder was observed.

〔Effect of the invention〕

Since the present invention has the above configuration, the following effects are achieved. That is, in the double coating layer type metal-coated metal sulfide powder according to the present invention, since zinc, tin, lead, or solder is present on the surface of the metal sulfide powder, these metals are present in the metal sulfide. reacts with sulfur to form sulfides. For that reason,
Compared to the case of using platinum group metals with less formation of this compound, the compatibility between zinc, tin, lead, or solder and metal sulfide is better, and the adhesion strength is also greater. In addition, in the diffusion/alloy reinforced type metal-coated metal sulfide powder according to the present invention, zinc, tin, lead, or solder forming the inner layer and copper, nickel, or cobalt forming the outer layer are diffused. Since it is alloyed, stronger adhesion can be provided.

The method for producing a double coating layer type metal-coated metal sulfide powder according to the present invention includes forming an inner layer selected from a zinc layer, a tin layer, a lead layer, or a solder layer on the surface of a metal sulfide powder by a hot-dip plating method. Since an outer layer selected from a copper layer, a nickel layer, or a cobalt layer is formed on the surface of these metal layers by a chemical plating method, processing can be performed simply and inexpensively, and bath management is also easy. In addition, since the method for manufacturing the diffusion/alloy-type reinforced metal-coated metal sulfide powder according to the present invention only heat-treats the double-layer type metal-coated metal sulfide powder at a relatively low temperature, the adhesion strength is improved. large metal-coated metal sulfide powders can be easily obtained.

The present invention therefore makes a significant contribution to the industrial production of ceramic powders such as molybdenum disulfide for metallization.

Claims (1)

[Claims] (1) The surface of the metal sulfide powder is double layered with an inner layer selected from a zinc layer, a tin layer, a lead layer, or a solder layer, and an outer layer selected from a copper layer, a nickel layer, or a cobalt layer. A metal-coated metal sulfide powder characterized by being coated. (2) The metal-coated metal sulfide powder according to claim (1), wherein the metal of the inner layer and the metal of the outer layer are mutually diffused or alloyed at least at the interface between the inner layer and the outer layer. (3) The surface of the metal sulfide powder contains zinc, tin,
A metal-coated metal sulfide powder characterized in that it is coated with a mutually diffused product or alloy of a metal selected from lead or solder and a metal selected from copper, nickel, or cobalt. (4) Put metal sulfide powder and metal powder selected from zinc powder, silver powder, lead powder, or solder powder into a container, and stir while heating to a temperature higher than the liquid phase generation temperature of the metal powder to produce metal sulfide powder. The surface of the metal is coated with an inner layer selected from a zinc layer, a tin layer, a lead layer, or a solder layer, and then the surface of the inner layer is coated with an outer layer selected from a copper layer, a nickel layer, or a cobalt layer by chemical plating. A method for producing a metal-coated metal sulfide powder, which comprises obtaining a metal-coated metal sulfide powder in which the surface of the sulfide powder is double coated with an inner layer and an outer layer. (5) The metal sulfide powder coated with the inner layer has a pH of 10 to 1.
3 into a solution of a complexing agent selected from Rossell's salt, citrate or ethylenediaminetetraacetic acid,
Next, formalin and a copper compound aqueous solution are added while stirring and maintaining the above pH to obtain a metal-coated metal sulfide powder in which the surface of the metal sulfide powder is double coated with an inner layer and an outer layer. Characteristic claim (4)
A method for producing a metal-coated metal sulfide powder according to . (6) The metal sulfide powder coated with the inner layer has a pH of 8 to 13.
The solution of a complexing agent selected from Rossel's salt or citrate was adjusted to
A reducing agent selected from sodium hypophosphite, hydrazine, or borohydride and an aqueous nickel compound solution are added while maintaining the metal sulfide powder surface to be double coated with an inner layer and an outer layer. The method for producing a metal-coated metal sulfide powder according to claim 4, characterized in that a coated metal sulfide powder is obtained. (7) The metal sulfide powder coated with the inner layer has a pH of 11 to 1.
3 into a solution of a complexing agent selected from Rossel's salt or citrate, and then, while stirring, the above p.
Sodium hypophosphite, hydrazine, while maintaining H.
Alternatively, a reducing agent selected from borohydrides and an aqueous cobalt compound solution are added to obtain a metal-coated metal sulfide powder in which the surface of the metal sulfide powder is double coated with an inner layer and an outer layer. The method for producing a metal-coated metal sulfide powder according to claim (4). (8) The metal-coated metal sulfide powder obtained by the production method according to any one of claims (4), (5), (6), and (7) is heated to a concentration of 250 to 700 in a reducing atmosphere or an inert atmosphere.
A metal-coated metal sulfide in which the metal of the inner layer and the metal of the outer layer are mutually diffused or alloyed at least at the interface between the inner layer and the outer layer, or the metal of the outer layer is softened by heating at ℃. 1. A method for producing a metal-coated metal sulfide powder, the method comprising obtaining a metal-coated metal sulfide powder. (9) The metal-coated metal sulfide powder obtained by the production method according to any one of claims (4), (5), (6), and (7) is heated to a concentration of 250 to 700 in a reducing atmosphere or an inert atmosphere.
By heating at ℃, the surface of the metal sulfide powder is coated with a mutual diffusion product or alloy of a metal selected from zinc, tin, lead, or solder and a metal selected from copper, nickel, or cobalt. A method for producing metal-coated metal sulfide powder, the method comprising obtaining metal-coated metal sulfide powder.