Reinforced Green Ceramic Shell Mould for Investment Casting Process

摘要

The development of thin ceramic shell mould in investment casting process is very crucial as this mould inherited brittle property and highly exposed to the cracking mechanism. The slurry composition produces green (unfired) ceramic shell mould which low in strength and easily cracks or fails during wax removal or handling process. By strengthening of this brittle ceramic shell mould via reinforcement technique can enhance the strength of green shell mould body. In this work, the presence of the treated rice husk fibre have toughened the green shell mould by creating mechanical interlocking bonding in shell matrix which contributes to higher modulus rupture value. In fact, SEM observations showed that the addition of fiber to the ceramic body to form a composite shell mould prevent the crack propagation mechanism due to the existence of the matrix-fibre bridging which create the resistance of fiber to pull-out. This directly will increase the strength of green shell mould body.