Dispersion Of Ultrafine Silicon Carbide Powder And Preparation Of Silicon Carbide Ceramics

Gelcasting (GC) is the small homogeneous composition with a body moldingshrinkage, which shows a clear body strength advantage over other molding methodsin the preparation of many oxides. GC molding not only means shaping, but evenbecome an important meaning of improving the material properties. Although the useof GC molding SSiC have been some reports, but look at the performance of thesintered body, using mechanical properties similar to the preparation of SSiC GCmolding compression molding, and not like other liquid phase sintering of ceramicsthat exhibit significantly improved, its causes worth exploring.CIP has the advantage of forming uniform force, less body internal defects, butbecause of restrictions on the formation mechanism, it cannot guarantee the accuracyof shapes and sizes. Therefore, this issue will be GC forming and molding combineCIP prepare high density, high strength dispersed SiC body. High-strength moldedbody can get all kinds of complex shape profiled products by machining; this featureis very suitable for high value-added products SSiC industrial production.This essay uses0.58μmSiC powder as a raw material, removing the elementalsilicon powder and elemental carbon by strong oxidizing pickling method. Study onCharacteristics of SiC fine powder dispersed in an aqueous solution to optimizedispersant, the pH of the slurry, and the surface of the powder with a coupling agentand a graft-modified PEG, success was obtained solid content was62vol%, viscosityof840mPa s (at a shear rate of50s-1) a low viscosity slurry of SiC. By controllingthe amount of initiator and reasonable gelling temperature, molding of the structure ofGC homogeneous SiC body, combined CIP molding eliminate residual pores in thegreen body and get high strength high density SiC body.Since the small amount of sintering aid and it is added in the form of distributionhas a great effect on the performance of SSiC. B4C and studied the impact of differentcarbon sources as sintering additives for SiC sintered density, as well as a sinteringaid in the dispersion of the slurry of ceramic material impact on performance. Finally,in2150℃for2h sintered to obtain a high density, high strength SiC ceramics. Thehighest density of the sintered sample was3.17g/cm3, microhardness24.3GPa, the flexural strength of486±7MPa, the fracture toughness of3.52MPa m1/2.