Study On Properties Of Three-dimensional Network Silicon Carbide/High Chromium Cast Iron Composite

More and more attention has been paid to three-dimensional network ceramic/metal composite materials.Three-dimensional network SiC ceramic/cast iron composite has been widely used in wearing area because of its excellent abrasive resistance.However,there are severe carbonation reaction between silicon and iron at high temperature.It's extremely unfavorable for the properties of composite materials.So,it's an effective way to make metallization of ceramic surface restrain interfacial reaction.The subject prepared SiC ceramic by adding silica sol and alumina as sintering aids,and analyzed structure and mechanical properties of ceramics.Then,SiC foam ceramics were prepared.In order to avoid carbonation reaction,iron coating was prepared on silicon carbide ceramic by chemical vaporous deposition.Three-dimensional continuous SiC ceramic/ High Chromium cast iron composite was prepared by vacuum expendable pattern casting.Finally,researched interfacial bonding,discussed the effect of the iron coating.The results are as follows:(1)The preparation of SiC ceramic and the research of performanceThe suitable process parameters to prepare the SiC ceramic are as follows: the temperature of sintering is 1480?,holding time is 3h,silica sol is 40% in sintering aids;The porosity of solid SiC ceramic is 28.4%,the volume density is 2.2g/cm3,the bending strength is 68.4Mpa.Silicon carbide ceramic particles are connected by glass phase.Sharp edges and corners of silicon carbide particles are blunted,and a small amount of silicon carbide is oxidized to silicon oxide.(2)The preparation of iron coating and its micro-analysisThe suitable process parameters to prepare the iron coating on the silicon carbide surface by chemical vapor deposition are as follows: the temperature of deposition is 650?,holding time is 1h,the hydrogen flow rate is 150 m L/min,argon flow rate is 200 m L/min.The iron coating obtained by these parameters is uniform and compact.There is trace reaction between iron coating and SiC ceramic by phase analysis.(3)The preparation of composites and its interface structure,performance detecting.After comparing the composites with coated and uncoated,they have same density,but uncoated composites' bending strength is lower than coated composites.There are many river patterns in the fracture morphology of composites.The way of fraccure is cleavage fracture.There are many holes because of ceramic particle extraction on fracture morphology,the way of fracture is intergranular fracture.In the fracture process of composites,the crack is firstly produced from the interface,the interface directly affects the mechanical properties of the composites.The abrasive wear test of composites shows that coated composites are better than uncoated composites.