Selective laser gelation of ceramic-matrix composites

This paper presents a layer manufacturing technology called selective laser gelation (SLG), combining selective laser sintering (SLS) and sol-gel technique, for fabricating ceramic-matrix composite green parts which are difficult to produce using conventional processes. The material used comprises stainless steel powder and a silica sol at a proportion of 65-35 wt.%. The metal-ceramic slurries are scanned using Nd:YAG laser. The metal particles are embedded in the gelled silica matrix to form a 3D composite part and are distributed over the silica gelled layers. The strengthened principle of this composite material is particle intension. In comparison with other processes for making composites, this approach features lower laser-forming energy and faster fabrication speed. A series of experiments was carried out to obtain the smallest pave-able layer thickness of 50 μm on an experimental rapid prototyping (RP) machine. The feasibility of this process was demonstrated by manufacturing a composite prototype with a bending strength of 45 MPa, a surface finish of 32 μm, and a dimensional variation of 10% under a laser energy density of 0.4 J/mm².