Densification, mechanical and microstructure properties of β-spodumene-alumina composites

New systems consisting of ceramic composites have been recently developed to replace conventional alumina as a substrate for high performance large scale integrated packaging. Few investigations on the beta-spodumene-alumina composites have been performed. Accordingly, the effect of beta-spodumene content on the sintering behaviour and mechanical properties of the beta-spodumene-alumina composites is the aim of the present study. Microstructural characteristics, thermal expansion and phase relations were also discussed. Fine beta-spodumene and alumina powders of high purity were synthesized by aqueous sol-gel processing. The gels were dried and calcined and the resulting materials characterized by XRD. Various compositions of beta-spodumene-alumina were prepared and conventional sintering studies were conducted at temperatures of 1400DG-1600DGC with soaking periods of 1-4 h. The obtained results showed that densification was reduced with the increase of beta-spodumene content. Mullite was detected in bodies containing 5% beta-spodumene. There was no evidence of mullite presence with higher contents of beta-spodumene. Increasing beta-spodumene from 5 mass% up to 15 mass% increased the bodies bending strength by = 43%, while the thermal expansion coefficient was slightly changed from 1.05 to 2.67 x 10-6/DGC in the range of 20DG to 1000DGC.