Research On Microstructure And Properties Of The Ceramic Surface Composite With High Chromium Cast Iron

As a new material,the research and development of metal matrix composites have been widely concentrated due to its advantages of high specific strength and high specific stiffness,especially in heavy industry.In this paper,the metal matrix composites of high chromium was prepared by the casting infiltration process,and tested in lab,it was found that the mechanical properties of the composite briquettes had been improved to a certain extent.In this paper,the ceramic surface composite with high chromium cast iron was prepared by casting infiltration process and its microstructure and properties was studied,especially focus on the effect of particle size of SiC and additive amount of the accessories.Under the condition of this experiment,four kinds of（80mesh,180mesh,10%180mesh+90%80mesh and 30%180mesh+70%80mesh）SiC particles were selected to prepare composite materials for reinforcing phase,most of the briquettes could be formed in 1.5～2.5mm composite layers.The experiment results showed that it had a significant influence on the microstructure and mechanical properties by the size of SiC particles.The effects of permeation-promoters,metal powder and rare earth compound on the microstructure and properties of the surface composites prepared by casting infiltration method were studied.The results showed that EPS powder has great influence on the microstructure and mechanical properties of the composites prepared by the casting infiltration process.The unmelted SiC particles were detected in the composite layer of some experimental castings by means of microstructure observation and X-ray diffraction analysis.For the reason,it was formatted that the metallurgical reactions of metals and coatings,some new phases such as Cr₇C₃,（Cr,Fe）₇C₃,Cr_1.36Fe_0.52,Cr_0.78Fe_2.22Si₂,Cr C in composite coating.Experiment results show that the wear resistance of composite layer of castings had increased 1.09 times in highest level.The alloy coating formula is:when V_SiC（80）:V_Cr-Fe=2:1,the amount of EPS is 0.5%,the addition of PVB is 1.2%,the addition of metal powder is 5%,and the addition of rare earth compounds is 3%.In this paper,the high-performance of the hardness was the composite coating with SiC（80 mesh）by adding EPS as the auxiliary material,which up to 1.09 times.