Study On RBSN-SiC Ceramics With The Preparation Of Retrieve Cut Metal Silico-Spindle Wire

Reaction bonded silicon nitride/silicon carbide, a composite with excellent properties, is a kind of refractory with high qualities widely used in ceramics, metallurgy, and so on.This paper explores the possibility that reclaimed silicon ingot by wire cutting is used as raw material. It also explores influences of particle grading of SiC, amount of Si powderadditive and the amount of sintering aids (a-Si3N4) on the matrix-phase, and the strength of the composite in the process of preparing Si3N4-SiC. The major contents andconclusions are as follows:In this paper, processing parameters were comprehensively investigated to achieve better mechanical strength and microstructure, experimental results indicate that:(1) The particle size composition has much effect on density of green body of RBSN bonded SiC materials.Changing the grading of SiC particles not only affects the strength and pile density, but also modifies the phase compositions and microstructure of the material. The best result is:40wt%6μm SiC,10wt%40μm SiC,40wt%120μm SiC and 20wt%6μm Si. At that time the density of RBSN bonded SiC materials is 2.276g/cm3,and the flexural strength is44.1MPa.(2) The bulk density and strength of RBSN bonded SiC materials increase with the increment of Si powder content. When the additive amount of Si varys from 15%to 30%in the batch composite of sample, the deustiy and strength of composite enhances step by step, they can attain to 2.46g/cm3 and 51.7 MPa respectively, otherwise the porosity decreases to 16.4%. From the XRD test we know that the excessive Si powder results in the increasing of residual Si content in the materials, which affects the strength of composite.(3) The phase composition of RBSN bonded SiC material has considerable effect on its microstructure and erties. The additives (a-Si3N4) are beneficial to the formation and development of Si3N4, and therefore the pores in the materials were filled, the apparent porosity decreased and the bulk density, and strengths increased. When the additive amount of a-Si3N4 is 5wt%, the content of a-Si3N4 in the materials attains to 26.3%, and the strength improves 18%more than in which a-Si3N4 was not added. While excessive sintering aids amount will exert a side effect.