UA125777C2 - Composite wear-resistant material - Google Patents

Abstract

The invention relates to powder metallurgy and concerns composite wear resistant material of Cr-Si-B-MgC2 system. The material contains, wt %: chromium 50-60, silicon 15-20, boron 10-15 and magnesium carbide 10-20. The technical result is in decreasing friction coefficients, wear intensity, increasing surface strength and corrosion resistance of coatings.

Description

The invention belongs to powder metallurgy, in particular, it concerns powder materials for gas-thermal spraying of functional coatings on the working surfaces of parts and mechanisms of any equipment, including aviation, operating in friction conditions, in the absence of lubricants or with their limitations, or in aggressive environments .

There is a copper-based sputtering material (USSR Copyright 5 1662119A1,

IPC C22S 9/01, 28.11.89, DSK), containing the following components (wt. 95): aluminum (9.5-12.2) 9o; iron (0.2-0.5) 95, nickel (0.01-2.8) 95; manganese (0.01-0.3) 95; silicon (0.01-0.2) 95; boron (0.01-0.015) 95; copper - the rest. This material has low microhardness, adhesive strength and brittleness under increased loads.

As a prototype, a well-known composition of powder antifriction material containing graphite (1-2) 95, magnesium (1-3) 95, copper (2.5-10) 905, titanium (8-12) 95, chromium - the rest (Patent) was used KO 2025529, IPC C22S 27/06, 0220 1/05, 30.12.1994). The specified material has a number of disadvantages, in particular, increased wear and friction coefficient at low temperatures without lubrication, as well as the use of a complex technological process in its production.

An important factor in choosing the composition of modern construction materials is the use of national natural resources.

The invention is based on the task of obtaining a composite wear-resistant antifriction material based on chromium by doping it with silicon and boron, with the addition of magnesium carbide, which provides a significant reduction in the coefficient of friction, an increase in wear resistance, corrosion resistance and adhesive strength.

The task is solved by the fact that the composite wear-resistant material containing chromium, according to the invention, also includes silicon, boron and magnesium carbide, in this ratio of components, wt. 9: chromium 50-60 silicon 15-20 boron 10-15 magnesium carbide 10-20.

In the conditions of studies of coatings, similar in structural and phase composition, applied by gas-thermal methods, it was established that the maximum operational properties correspond to coatings sprayed by the detonation-gas method. The selection of optimal spray modes makes it possible to obtain materials with high antifriction properties.

The introduction into this chromium-based composition of magnesium carbide as a modified additive in combination with the rest of the components ensures the formation of a surface layer due to

From carbide graphite with high anti-friction properties, which minimizes adhesive-molecular interaction, contributes to low resistance to frictional forces and high wear resistance, while partially reducing the crystallization temperature of the original St-51i-B system.

The proposed anti-friction material can be used as a material for parts of machines and mechanisms of tribotechnical purpose, operating in the absence of 35 lubricant or with their limitations, as well as in aggressive environments.

The material is obtained by powder metallurgy methods.

The initial powders of chromium, silicon, boron and magnesium carbide are mixed and ground in the appropriate ratios in an acetone or rectified alcohol medium in a planetary mill for 6-8 hours. The mixture is dried in a drying cabinet, and then sifted through a sieve. 40 The average particle size does not exceed 15-20 μm. Samples are obtained by hot pressing in graphite molds in the temperature range of 1480-1500 "С, at a pressure of 20-

MPa, exposure time 10 minutes. The residual porosity of such samples does not exceed 1.5-3 95.

The physico-mechanical and tribotechnical properties of the material were determined on the obtained samples: friction coefficient, wear intensity, bending strength, which are listed in Table 1.

Example 1

Chromium powder 50 wt. 95, silicon 20 wt. 95, boron 15 wt. 95, magnesium carbide 15 wt. 95 are mixed and ground in the appropriate ratios in the medium of acetone or rectified alcohol in a planetary mill for 6-8 hours. The mixture is dried in a drying cabinet, and then sifted through a sieve. The average particle size does not exceed 15-20 μm. Samples are obtained by the method of hot pressing in graphite molds in the temperature range of 1480-1500 "С, at a pressure of 20-30 MPa, holding time is 10 minutes. The residual porosity of such samples does not exceed 1.5-3 95.

Example 2

Chromium powder 55 wt. 95, silicon 15 wt. 95, boron 13 wt. 95, magnesium carbide 17 wt. 95 are mixed and ground in the appropriate ratios in the medium of acetone or rectified alcohol in a planetary mill for 6-8 hours. The mixture is dried in a drying cabinet, and then sifted through a sieve. The average particle size does not exceed 15-20 μm. Samples are obtained by the method of hot pressing in graphite molds in the temperature range of 1480-1500 "С, at a pressure of 20-30 MPa, holding time is 10 minutes. The residual porosity of such samples does not exceed 1.5-3 95.

Example C

Chromium powder 60 wt. 95, silicon 18 wt. 95, boron 12 wt. 95, magnesium carbide 10 wt. 95 are mixed and ground in the appropriate ratios in the medium of acetone or rectified alcohol in a planetary mill for 6-8 hours. The mixture is dried in a drying cabinet, and then sifted through a sieve. The average particle size does not exceed 15-20 μm. Samples are obtained by the method of hot pressing in graphite molds in the temperature range of 1480-1500 "С, at a pressure of 20-30 MPa, holding time is 10 minutes. The residual porosity of such samples does not exceed 1.5-3 95.

Example 4

Chromium powder 57 wt. 95, silicon 14 wt. 95, boron 12 wt. 95, magnesium carbide 17 wt. 95 are mixed and ground in the appropriate ratios in the medium of acetone or rectified alcohol in a planetary mill for 6-8 hours. The mixture is dried in a drying cabinet, and then sifted through a sieve. The average particle size does not exceed 15-20 μm. Samples are obtained by the method of hot pressing in graphite molds in the temperature range of 1480-1500 "С, at a pressure of 20-30 MPa, holding time is 10 minutes. The residual porosity of such samples does not exceed 1.5-3 95.

Example 5

Chromium powder 53 wt. 95, silicon 17 wt. 95, boron 14 wt. 95, magnesium carbide 16 wt. 95 are mixed and ground in the appropriate ratios in the medium of acetone or rectified alcohol in a planetary mill for 6-8 hours. The mixture is dried in a drying cabinet, and then sifted through a sieve. The average particle size does not exceed 15-20 μm. Samples are obtained by the method of hot pressing in graphite molds in the temperature range of 1480-1500 "С, at a pressure of 20-30 MPa, holding time is 10 minutes. The residual porosity of such samples does not exceed 1.5-3 95.

Table

Composition and properties of wear-resistant material .. Intensity | Strength. Coefficient of shi -.8 μm/km MPa sgiv5|v/|mosi|s|mo|sy|t! 71717 1 50 20115, 15 | - 1 - | | | 02 | 47 | 6 2 |55 15113 17 | - 1-1 | | oh 43 | 642 with | 60 t18|12| lo | - 1 - 1 | | 007 | with | 690 4 |57 14|12| 17 |-1- 1 | 11 009 | 37 | 679 5 1|53117|14| 16 | - 7-1 | | oz | 49 | 623 and Gv80Ї1 HER HER 21315110 021 | 54 | in

Coo)

The dependence of the wear resistance of coatings on the amount of magnesium carbide within the studied limits is monotonous. At the same time, there is a correlation between the kinetic parameters of the surface layer formation process and its physical and mechanical properties. Sputtering regimes that lead to an increase in the amount of wear-resistant phase in the coating correspond to an increase in its wear resistance.

The bending strength was determined according to the standard method approved by the European Standard IZO/15 206 at 4-point bending for samples measuring 45x4x3 mm.

Mechanical processing of the surface with diamond wheels was carried out along the length of the samples. Chamfers were removed along the ribs.

The coefficient of friction (Her) and the intensity of wear (I, μm/km) were determined according to the scheme of the shaft-insert according to the method of work (3.7. Mamkin, M.K. Kovpak, A.I. Yuga, etc. Complex of machines and methods of determining antifriction properties materials during sliding friction//

Powder metallurgy, 1973, Mo. 1, p. 67-72.).

The proposed coatings can be used for surface strength and wear resistance of parts in conditions of friction without lubricants and with limited lubrication or in aggressive operating environments for parts operating in extreme conditions of friction.

Claims (1)

FORMULA OF THE INVENTION Composite wear-resistant material containing chromium, which is distinguished by the fact that its composition also includes alloyed impurities, which are silicon, boron and magnesium carbide, in this ratio of components, wt. 9o: chromium 50-60 silicon 15-20 boron 10-15 magnesium carbide 10-20.