Experimental studies on electrical discharge machining of silicon nitride titanium nitride Si3N4 TiN ceramic composites

Abstract

In the current trends, most of the Ceramic Matrix Composites (CMCs) are used in the field of engineering materials than the conventional materials. Compared to conventional metals and its alloys, CMCs are more efficient, effective and durable. Si3Ni4 based composites have better physical, chemical and mechanical properties than other ceramic materials like ZrO2, SiC, B4C, Al2O3, etc. Due to their superior mechanical properties, CMCs find wide application in Ceramic Matrix Composites. Si3N4 based composite materials have vital application in gas turbines, heat exchangers, air craft engine, ball bearing, wear-resistant parts, shot blast nozzle, level sensors in molten metal, etc. Experimental investigations on various types of CMCs revealed that these composites have very less machinability because of its properties. Due to very high strength and greater hardness, it is difficult to employ traditional machining method to produce complex shapes as it may cause cracks on the machined surface. CMCs are non-conductive in nature and very few like titanium nitride aluminum oxide, molybdenum disilicide silicon carbide and silicon nitride titanium nitride are intentionally manufactured to conduct electricity and thus EDM is possible in these composite materials. Using the mixture of Si3N4 and Ti powders, Si3N4 TiN composite materials are produced by hot pressing process and spark plasma sintering (SPS) method at high temperature range of 1250 to 1350°C. Silicon nitride titanium nitride composites prepared by SPS process possess low electrical resistivity and thus EDM process is possible. newline