Research On The Preparation Processing Of SiC Particles Reinforced Steel Matrix Surface Composite Material

About 75%-80% of machine parts failures are caused by wear. Along with the development of modern industry, it is in urgent need of new materials, which are anti-erosion and anti-abrasion, and can be used at high temperature and high speed. In recent years, the particles reinforced metal matrix composite materials have been attracted because they have the characteristics of stability at high temperature, good ductility, good erosion resistance and abrasion resistance.The SiC particle reinforced steel matrix surface composite was prepared by EPC (Expandable pattern casting) penetration processing, which combines with the EPC processing and casting penetration processing, based on the consideration of erosion-wear conditions. The effects of SiC particles sizes, adhesion agents of SiC performs and preparation processing parameters on the depth of casting penetration and fusion qualities. The results showed that the main factors which affect penetration layer microstructures, penetration speed and penetration deepness are wettability between SiC particles and liquid steel, vacuum degree, pouring temperature and penetration constituents. The clay, boric acid and sodium fluoride added in SiC performs could prevent from the SiC particles decompose and protect the SiC particles. Silicon decomposed from SiC particles would promote the carbons graphitization which were from the SiC decomposes. The main research results are as follows:(1) The appropriate particles sizes of SiC used to prepare surface composite on the steel surface are 20 mesh ～ 30 mesh, which can promote the penetration of liquid steel and prevent the SiC particles form decomposing completely.(2) The better penetration effects would be gained when the SiC performs were used the 2% clay as adhesion agent and 2% sodium fluoride and boric acid as additives. There are obvious penetration layer, transition zone and matrix zone on this surface composite.(3) The surface composite layer which contains SiC particles with better wear resistance could be formed on the surface of steel casting by infiltration of 0.35C steel into SiC particles. The composite layer was flat, and the SiC particles distributed uniform. The casting penetration processing was stable, and operated convenient.(4) The thermodynamic and kinetic of the formation of SiC particles composite layer had been discussed. The necessary conditions for the formation SiC particles composite layer were pointed out.The research results showed that the surface composite layer on surface of steel could be prepared by casting penetration processing. This supplies a new method for preparation of particles reinforced metal matrix composite materials.