SU1588799A1 - Method of producing coatings - Google Patents

Abstract

The invention relates to methods for producing coatings of powder materials by thermal thermal methods and can be used to create protective layers on parts. The purpose of the invention is to increase the adhesion strength of coatings. According to the invention, a powder consisting of a mixture of metal and 10-30% glass is applied to a steel substrate heated to 300-500 ° C, the temperature of which is maintained at a predetermined interval during the spraying process. An increase in the adhesion strength is achieved due to the interaction of the glass with the oxide film of the substrate and the formation of a juvenile-clear surface. In this way, the entire thickness can be applied or a sublayer is formed. 1 hp f-ly, 4 tab.

Description

The invention relates to methods for producing coatings of powder materials by thermal thermal methods and can be used for applying protective layers on parts.

The purpose of the invention is to increase the adhesion strength of coatings.

According to the proposed method, a powder consisting of a mechanical mixture of metal powder and 10-30% glass is applied on a steel substrate heated to 300-500 0. During the sputtering process, the substrate temperature is maintained at this interval.

The implementation — prior to spraying, the preheating of the substrate to 300–500 ° C is the formation of its nor

surfaces of a chemically active oxide film. The glass particles present in the charge as a result of melting in a high-temperature gas jet when they hit the substrate actively interact with its oxide film, and partly its solution. As a result, around the points where glass particles hit the surface of the substrate, short-term portions free from oxides of the formed juvenile surfaces actively enter into a physicochemical interaction with the impact of metallic particles on the surface. As a result, the adhesion strength of such particles to the substrate is significant rises.

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Preheating the substrate before spraying to a temperature of less does not provide a significant increase in the adhesion strength of the coatings due to the relatively low temperature activation of the substrate surface. On the other hand, heating to temperatures leads to an excessively intense increase in the thickness of the oxide film, which prevents the softened glass particles falling on the surface of the substrate to completely remove the oxide film in the impact zone.

An increase in the adhesion strength of the coating to the substrate is also observed if only the first layer is sprayed onto the substrate heated to 300-500C.

Dp of obtaining the coating was prepared by preparing the mixture by mechanical mixing for 30 minutes, consisting of metal powder and powder of VVS glass with a particle size of 40-100 microns. During the preparation of the charge, the volume content of the glass phase was varied from 0 to 50%. The adhesion strength of the coatings was measured by the pin method. Iron powder PZhRV, nickel PNE-1, nichrome P-N80X20 and PG-19M-01 copper alloy was used as the metal.

Before sputtering, the steel samples were heated with a plasma jet at various temperatures. During the deposition of the PG-19M-01 copper alloy mixed with glass, the substrate temperature was maintained only when the first layer was applied. Then the substrate was cooled and subsequent layers were sprayed without heating. For the heating and dusting of the powder material, a Plasma-.Technik installation (Switzerland) was used. An argon-hydrogen mixture was used as a plasma-forming and transporting gas.

The results of the study of the adhesion strength of the obtained coatings are presented in Tables 1-4. The adhesion strength of the coatings from the mixture of iron-stee, clo, is presented in table

Bonding strength of coatings from

nickel-glass mixtures are presented in

table 2

The adhesion strength of coatings from a mixture of nichrome-glass is given in table 3.

The adhesion strength of coatings from a mixture of bronze-glass is given in Table 4.

As can be seen from the data of Tables 1–4, the greatest increase in the adhesion strength is achieved when the glass content in the charge is 10–30% (the data corresponding to the well-known one are given in the graph)

Table 5 shows the adhesion strength of the coating, the first layer of which is; He deposited on the heated substrate while maintaining, during the spraying process, the temperature reached by the mechanical mixture of iron powder PZHRV and glass. Subsequent coating layers are pure iron.

Claims (2)

1. A method of producing coatings, mainly on the surface of ferrous metals, comprising spraying a mixture of metal powder with 10-30% glass onto a substrate, characterized in that, in order to increase the adhesion strength of the coatings, the substrate is preheated to a temperature of 300-500 s, which keep unchanged during the spraying process. 2. The method according to claim, characterized in that at a substrate temperature of 300-500 ° C at least the first coating layer is sprayed. Table 1 Table 2 Table4