RU2367696C2 - Metallo-matrix composite - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: composite contains tin, stibium, copper and silicon carbide particles, at following ratio of components, wt %: stibium - 10.0-12.0, copper - 0.5-1.5, silicon carbide - 1.0-15.0, tin - the rest.

EFFECT: increasing of antifrictional and mechanical properties, increasing of temperature durability of material.

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Description

The invention relates to composite materials, in particular to metal matrix composites. It can be used in machine, automotive, petrochemical industry in the production of plain bearings.

Metal matrix composites are known, consisting of an aluminum matrix and reinforcing elements in the form of silicon carbide powder [Axel Kolsgaard, Stig Brusethaug Settling of SiC particles in an AlSi7Mg melt. Materials Science and Engineering, A 173 (1993), 213-219]. Such a metal matrix composite has good antifriction properties, but it has a low corrosion resistance.

Also known metal-matrix composite containing a copper matrix and reinforcing elements of silicon carbide (RF patent No. 2017852, IPC C22C 32/00, publ. 08/15/1994, 3 S.). Such a metal-matrix composite has increased wear resistance compared to conventional bronzes, but is not technologically advanced in the manufacture and repair of equipment.

The closest to the claimed metal matrix composite material by purpose and composition are tin-babbitt-based alloys according to GOST 1320-74 (ISO 4383-91) [1], which contain the following main elements, wt.%: Antimony 10.0- 12.0, copper 5.5-6.5, tin else.

These alloys are recommended for use in the manufacture of sliding bearings operating in various, including heavily loaded, machines and assemblies in various industries and national economy. However, tin-based alloys have low mechanical properties and a low allowable temperature during operation

An object of the present invention is to provide a metal matrix composite material having improved antifriction and mechanical properties and increased temperature resistance. Obtaining a composite metal matrix alloy with a higher level of the stated properties provides an increase in the operational reliability and overall service life of machines and assemblies where plain bearings are used.

The problem stated in the application is solved in that the metal matrix composite containing tin, antimony, copper, additionally contains particles of silicon carbide in the following ratio of components, wt.%: Antimony 10.0-12.0, copper 0.5 - 1.5, silicon carbide 1.0-15.0, the rest is tin.

The proposed composite material was made as follows. Babbitt B83 was melted in a resistance furnace under a layer of charcoal. After reaching a temperature of 350-400 ° C, a coating layer of charcoal was removed and then silicon carbide powder was introduced. Silicon carbide powder was introduced into molten babbitt by mechanical kneading. The resulting composite alloy was poured into a metal mold. Samples were cut from the obtained ingots to determine hardness and antifriction properties.

The stated technical result is achieved in that the dispersed particles of silicon carbide introduced into the matrix are additional, in addition to SnSb intermetallics, support points located in a soft matrix. A roughness is formed on the rubbing surface of the bearing, leading to the creation of micro-bearings that form micro wedges from the lubricant, translating the bearings from boundary friction to liquid or semi-liquid. Lubricant micro-wedges, as well as solid SnSb intermetallic compounds protruding from the soft base, and dispersed silicon carbide particles are capable of perceiving higher normal pressure of the rubbing pair than in the known alloy and lowering the friction coefficient, i.e. to improve the antifriction properties of the metal matrix composite material. With all this, it was possible to reduce the copper content in the alloy without compromising service properties.

Table 1 shows the options for the proposed composite alloy.

Table 1 Components Composition, wt.% Prototype Alloy number one 2 3 four antimony 10.0 10.5 11.0 12.0 11.0 copper 0.5 0.6 0.8 1,5 6.0 silicon carbide 1,0 5 10.0 15.0 - tin rest rest rest rest rest

The results of the comparative tests are presented in table 2.

table 2 Structure Hardness, HB Maximum load during testing, MPa Coefficient of friction Oil temperature, ° С Composition 1 25 4.0 0,03 45 Composition 2 thirty 5,0 0,03 48 Composition 3 40 10.0 0.02 55 Composition 4 fifty 13.0 0.01 85 Prototype twenty 2.0 0.04 45

As follows from the data of table 2, the proposed metal-matrix composite material has a higher hardness, allows higher friction loads and a higher temperature and at the same time has a lower coefficient of friction.

The content of silicon carbide in the composite of less than 1% does not significantly reduce the coefficient of friction, and an increase in concentration of more than 15% leads to a deterioration of technological properties. It is possible to reduce the copper content in the composite alloy with additives of silicon carbide due to the appearance of additional supporting surfaces, which leads to an increase in the bearing load of the composite with a lower copper content.

Claims (1)

A metal matrix composite containing tin, antimony, copper, characterized in that it additionally contains silicon carbide particles in the following ratio of components, wt.%:
antimony 10.0-12.0 copper 0.5-1.5 silicon carbide 1.0-15.0 tin rest