SU1118485A1 - Method of obtaining coating from powder - Google Patents

Abstract

A METHOD FOR PREPARING A CARBBUE COATING OF POWDER, including applying a layer of powder on the surface, placing an intermediate sheet element on it and blasting, characterized in that, in order to increase the strength of the connection of the coatings to the metal surface, before applying to the surface, the powder is moistened with a liquid carbon-containing substance .

Description

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; l The invention relates to powder metallurgy, in particular, to a method of coating powders of carbide-forming metals on a metal surface, and can be used to apply wear-resistant coatings to parts operating under conditions of increased wear, high temperature, and aggressive media. A known method of applying carbide coatings on the surfaces of carbide-forming metals of the 4th group of the periodic system consists in successively applying a liquid carbon-containing, diffusing substance, an insulating material and an explosive to the surface of a component. The initiation of the detonation of an explosive leads to the release of energy, which is realized in a shock wave having a high temperature above and a pressure of more than 200 kbar. With the passage of a shock wave into the layer of liquid carbon-containing substance, it decomposes into atomic carbon, which saturates the surface layer of the carbide-forming metal with the formation of metal carbide lj. I. The disadvantage of this method is that it allows to obtain carbide coatings only on the surface of parts made of carbide-forming metals IV of the group of a periodic theme. In addition, carbide coatings with a thickness of no more than 100 microns are obtained in a known manner, which limits its use. The closest to the proposed technical essence and the achieved result is the method of producing a carbide powder coating, which includes applying a layer of powder on the surface, placing an intermediate sheet element on it and blasting the zj. A disadvantage of the known method is the low strength of the middle of the coating with a metal surface. The purpose of the invention is to increase the strength of the joint between the coating and the metal surface. The goal is achieved by the fact that according to the method of obtaining a carbide coating from a powder, including applying a layer of powder on the surface, placing an intermediate sheet element on it and blasting, before applying it to the surface, the powder is moistened with liquid carbon containing liquid. When an explosive is detonated, a shock wave is formed, which is a pressure surge (up to 250 kbar) and temperatures of 1500 ° C in an area called the shock front, the direction of motion of which coincides with the direction of propagation of the detonation process. A braid shock wave, formed by sliding detonation of an explosive, passes through an insulating material and acts on a powder wetted with a binding liquid carbon-containing substance, which decomposes to atomic carbon under the action of high pressure and temperature. The carbide-forming metal powder, heated to the melting temperature due to the impact of the shock wave and intense shear flow behind the oblique wave front, interacts with carbon, thus forming metal carbide (MeC). Intense shear flow of the powder in contact with the surface layer of the substrate material provides heating of the surface layer of the predog with the formation of the melt zone of this layer, saturation of the melt with a carbidized metal powder leads to the formation of a strong adhesion of the coating to the substrate. The method is carried out as follows. The metal surface of steel, previously cleaned from scale, oxide film and contamination, is made of steel, st. 3, aluminum AD1 or copper Ml, whose thickness is 15 mm, is applied a layer of nickel, molybdenum or tungsten powder moistened with either carbon tetrachloride, or benzene, or chlorobenzene, or glycerol, or methyl alcohol, or formic acid, or carbon sulphide or industrial oil, either vaseline, or separator, or spindle, or machine. The size of the particles of nickel powder 60-70; molybdenum 60-70, tungsten 50 microns, tol1 one layer of powder impregnated with carbon-containing substances or industrial oil,

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is 0.8-1 mm. An intermediate sheet of vinyl plastic 0.4 mm thick is placed on the surface of the powder, on which the explosive charge of the substance is placed, plastic plastic material G-75, the thickness of the layer So - mm is the detonation velocity O 7.4 km / s.

The search for detonation is carried out with an ED-8e electric cone.

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Data on the adhesion strength of the coating to the metal surface, obtained by the known and proposed method, are presented in Table 5

As follows from the above data, the proposed method provides a higher adhesion strength of the coating to the metal surface.

Claims (1)

METHOD FOR PRODUCING CARBIDE COATING FROM POWDER, including applying a layer of powder on a surface, placing an intermediate sheet element on it and blasting, characterized in that, in order to increase the bond strength of the coatings with a metal surface, the powder is moistened with a liquid carbon-containing substance before being applied to the surface. i □ O>