JPH04350102A - Production of metal coated composite powder - Google Patents

Abstract

PURPOSE:To obtain metal coated composite powder having uniform structure by mixing a metal foil and/or a fragment of the foil of various metal and its alloy having specific thickness with powder and by coating the powder with the foil and/or the fragment of the foil. CONSTITUTION:The metal foil and/or the fragment of the foil of gold, platinum, palladium, silver, indium, tantalum, titanium, zirconium, molybdenum, cobalt, niobium, tungsten, aluminium, nickel, iron, chromium, copper, tin, lead, zinc and its alloy having <=10mum thickness is mixed with the powder of an optional metal, inorganic material, and organic material by mechanical power such as a vibration mill to apply the foil and/or the fragment of the foil on the powder to composite.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a method for producing an inexpensive and uniform metal-coated composite powder, and the obtained metal-coated composite powder can be used as a filler for conductive paints, magnetic materials, electromagnetic shielding for radio wave absorption, etc. It can be used in the following fields.

0002

[Prior Art] As a method for manufacturing metal-coated composite powder, individual powders are coated by displacement plating, electroless plating, chemical vapor deposition, physical vapor deposition, vacuum evaporation, alkoxide method, etc. to form a composite powder. There is a way to make it.

However, the above methods have drawbacks such as high manufacturing costs, limited materials that can be coated, and many technical problems during mass production, and only a few have been put into practical use and are expensive. be. In addition, if coating the powder is easy and it is possible to combine different materials, regardless of whether they are metals, inorganic materials, or organic materials, it is possible to design various metal-coated composite powders. There's no way.

Displacement plating and electroless plating are used industrially as methods for producing metal-coated composite powders, but
There were many problems, such as not only problems with wastewater treatment of plating solution and work environment, but also problems such as not being able to coat each powder uniformly, making it impossible to obtain a uniform coating.

[0005]

OBJECTS OF THE INVENTION The present invention has been made as a result of intensive research into a method for producing metal-coated composite powder that is inexpensive, has a uniform coating thickness, and is coated uniformly on each individual powder.
We have discovered and completed that by using metal foil and/or foil pieces as the coating material, it is possible to select any combination of materials that have the above features and can be coated.

[0006]

[Means for Solving the Problems] The present invention provides gold, platinum, palladium, silver, indium, tantalum, titanium, zirconium, molybdenum, cobalt, niobium, tungsten, aluminum, nickel, iron, chromium, copper, tin, and lead. ,
A metal characterized by mixing powder with a metal foil and/or foil piece of zinc or an alloy thereof with a thickness of 10 μm or less, and uniformly coating the powder with the metal foil and/or foil piece by mechanical mixing force. This is a method for producing coated composite powder.

That is, the present invention is a method for producing metal-coated composite powder by coating the surface of any metal, inorganic, or organic powder using metal foil and foil pieces as coating materials.

[0008] In the present invention, the effect is recognized when the metal foil and/or foil piece used as the coating material has a thickness of 10 μm or less, but the thinner the foil, the better, preferably 1 μm or less. Further, the size of the foil piece is not particularly limited.

[0009] In the method of coating powder with metal foil and foil pieces, powder having a dense coating on the powder surface can be obtained by mixing the metal foil and foil pieces in a container containing media in a predetermined amount.

[0010] In the manufacturing method of the present invention, a vibrating mill, a rotary ball mill, or the like is preferable as a processing machine for mixing and compounding the powder and the metal foil and/or foil pieces. That is, this is because the impact of the balls generated during milling of the mixed powder particles progresses and composes the particles.

Oxidation of the base metal-coated composite powder can be prevented by inactivating the atmosphere during the coating process. In other words, when coating with a metal that is easily oxidized, it is preferable to perform the coating in an inert gas atmosphere because there is a risk of surface oxidation. As a method of preventing oxidation of the composite powder even in an air atmosphere, it is also possible to add a treatment agent for oxidation prevention in advance and perform a coating treatment at the same time.

[0012] In order to improve functions such as dispersion and viscosity in a paint by using the metal-coated composite powder as a filler, a treatment agent can be added in advance and coating treatment can be carried out at the same time. Since the amount of metal foil and/or foil pieces to be mixed can be changed arbitrarily, the amount of coating can be changed freely.

[0013]

[Operation] In the conventional mechanical alloying method, powder is used as the coating metal and the powder to be coated is mechanically joined, but this requires a large amount of energy and has very low productivity. . In terms of quality, it was difficult to coat uniformly, and the conductivity of the coating film was particularly poor when compared with electroless plating as a filler for a conductive material. However, in the present invention, by using thin and uniform metal foil and/or foil pieces as the coating material, even with weak mechanical mixing in a dry state, the foil and foil pieces can be coated on the powder surface. This is because it can be covered uniformly. Therefore, the yield of the product is also good. Because it is a dry process, it is easier to handle the coated composite powder compared to other methods.
There is no need to worry about waste disposal.

[0014] Vibration mills and rotary ball mills have shown excellent effects as methods for performing this composite treatment, but the present invention is capable of processing even if the impact effect of the balls in the mill is much weaker than that of conventional mechanical alloy powders. , metallization can proceed with very low energy consumption. The reason why the composite powder of the present invention exhibits excellent performance is probably because the powder is coated with a thin foil piece, so that uniform coating can be achieved.

[0015]

[Example] Next, an example of the present invention will be shown.

Example (1) 10 parts by weight of silver foil with a thickness of 0.2 μm and an average particle size of 20 μm
90 parts by weight each of copper powder, nickel powder, iron powder, stainless steel powder, permalloy powder, zirconia powder, alumina powder, glass powder, polyimide resin powder, and acrylic resin powder in a diameter of 10 m.
Mixing and coating treatment was carried out with 100 parts by weight of zirconia balls of 1.0 m in an air atmosphere using a rotary pot mill at 50 rpm for 6 hours. As a result, it was found that the silver foil pieces were uniformly coated with each of the powders.

Example (2) Gold, platinum, palladium, silver, indium, tantalum, titanium, zirconium, molybdenum, cobalt, niobium,
Tungten, aluminum, iron, chromium, copper, tin, lead,
10 parts by weight each of zinc and stainless steel foils with a thickness of 1 μm, 90 parts by weight of nickel powder with an average particle size of 100 μm, and 2 parts by weight with a diameter of 2
The mixed coating treatment was carried out in a vibrating mill in an air atmosphere with 100 parts by weight of 5 mm steel balls for 6 hours. As a result, it was found that each piece of metal foil was uniformly coated with the nickel powder.

Example (3) 10 parts by weight of silver foil with a thickness of 0.2 μm and an average particle size of 20 μm
90 parts by weight of copper powder and 0.5 parts by weight each of stearic acid, a titanate coupling agent, an aluminum coupling agent, and a silane coupling agent as additives were placed in an air atmosphere together with 100 parts by weight of a steel ball with a diameter of 12 mm. Mixing and coating treatment was carried out using a rotary pot mill at 50 rpm for 6 hours. As a result, it was found that even when additives were added, the silver foil pieces were uniformly coated on each powder. In addition, when additives were added, it was confirmed that the dispersibility was good during kneading in the paint.

Comparative Example (1) 10 parts by weight of silver powder with an average particle size of 3 μm and 90 parts by weight of copper powder with an average particle size of 20 μm were mixed together with zirconia balls of 10 mm in diameter in an air atmosphere with a rotating pot mill at 50 rpm for 6 hours. Although coating treatment was performed, no silver coating was observed on the copper powder.

[0020]

[Effects of the Invention] As explained in detail above, the manufacturing method of the present invention has a lower manufacturing cost and can be safely mass-produced than the conventional manufacturing method of metal-coated composite powder. Furthermore, materials can be selected arbitrarily, and metal-coated composite powders can be designed freely. Moreover, since uniform coating is possible, a metal-coated composite material can be produced that fully takes advantage of the characteristics of the coated metal even with a small amount of coating. It is particularly suitable as a filler for conductive paints, and can also be used as a filler for composite resins with excellent electrical and magnetic properties.

Claims (1)

[Claims] [Claim 1] Thickness of gold, platinum, palladium, silver, indium, tantalum, titanium, zirconium, molybdenum, cobalt, niobium, tungsten, aluminum, nickel, iron, chromium, copper, tin, lead, zinc, and alloys thereof. The metal foil and/or foil pieces with a diameter of 10 μm or less are mixed with powder, and the above metal foil and/or foil is mixed by mechanical mixing force.
Alternatively, a method for producing a metal-coated composite powder, which comprises uniformly coating the powder with a piece of foil.