The effect of water on the behaviour of alumina-paraffin suspensions for low-pressure injection moulding (LPIM)

The properties of ceramic powder-paraffin suspensions for low-pressure inje ction moulding (LPIM) is of critical importance to the successful productio n of high quality ceramic parts. Due to the high hygroscopicity of fine alu mina powder, water introduced into the suspension at any stage of the produ ction prior to sintering, may significantly influence its rheological behav iour and hence determine the process parameters as well as the properties o f the sintered ceramics. In the industrial environment humidity cannot easi ly be avoided. Its effect is usually detrimental - it causes flocculation, which is usually the source of defects in sintered ceramics. However, accor ding to the results of the present work, the effect can also be put to good use. Penetration of water into the as-moulded green parts facilitates bind er removal and prevents defect formation during this processing step. (C) 2 000 Elsevier Science Ltd. All rights reserved.