A. Z. -, I. F. -, Faculty of Engineering, University of Indonesia, Depok, Indonesia
This research is to study the effects of firing temperature and holding time on production of SiC/Al Ceramic Matrix Composites (CMC) and characterization of this materials produced by Directed Metal Oxidation (DIMOX). The firing temperature and holding time used are varied from 900oC to 1300oC with holding time for 10 and 20 hours respectively. The characterizations of composites are examined such as density, porosity, hardness, and microstructure analysis.
The results showed that SiC perform has been infiltrated by Al liquid occurred optimally on firing temperature of 1100oC with holding time for 20 hours. Ceramic composites produced have highest density of 3,54 gram/cm3 can be obtained at this condition, while porosity tents to increase with increasing firing temperature. Porosity within the channels is associated primarily with insufficient Al flow to feed the solidification shrinkage. The highest hardness can be obtained on firing temperature 1300oC with holding time for 10 hours i.e. 1820 VHN. Distribution of SiC particles spread over SiC/Al composites product., and around SiC particles can be found Al, spinel (MgAl2O4), Al2O3 and Mg2Si analysed by EDS.
Key Words : DIMOX process, SiC/Al composites, Firing Temperature, Holding time
Summary: SiC/Al Ceramic Matrix Composites can be produced by Directed Melt Oxidation (DIMOX) at 1100oC for 10 hours. The molten Al flow to feed pores through the channel of SiC preform by capilarity force. The temperature firing used in this process varied from 900, 1100 and 1300 oC for 10 and 20 hours respectivelly. The characterisation of SiC/Al composites is conducted by examined the porosities, densities, hardness, and gain product as well as microstructural analysis. It is found that firing at 1100 oC is optimum condition due to gain product, densities and hardness are increased both at firing for 10 and 20 hours respectivelly. In contrast porosities are also increased however, it's expected decreased. Increasing porosities up to 3.5%Vf due to Al melt did not feed the channel around SiC particles perfectly.
