Abstract:A novel method for fabricating the silicon carbide ceramic preforms by using selective laser sintering (SLS) technology was proposed. The sintering properties with SiC surface modification, the sintering characteristic of SiC ceramic powders, and the debinding and infiltration process of SiC preforms were studied. The results show that the sintering characteristics of SiC ceramic powders with silane coupling reagent KH-570 are greatly improved. And then the contents of inorganic binder NH4H2PO4 are limited to 8%. The energy density is within the scope of 0.10−0.12 J/mm2. The density and bending strength of sintering samples under energy density of 0.11 J/mm2 is 2.31 g/cm3 and 0.81 MPa, separately. The prepared samples, when debinded and infiltrated, were characterized by XRD and OM. It can be inferred that the SiP2O7 is a sort of new binder in debinding samples, and a few of new AlPO4 phases are formed in the infiltrated process, and not only the composites dense but also SiC particles are distributed homogenously. In addition, the figure and size of prepared products are in accord with its CAD model.

Key words: silicon carbide ceramic; preforms; selective laser sintering; surface modification; laser energy density