Effect of Processing Parameters and Additives on Partially Sintering of Si۳N۴-MoSi۲ Composite

Addition of MoSi۲ to Si۳N۴ matrix leads to an improvement in the mechanical properties and oxidation resistance as well as an increase in the electrical conductivity of the produced composite, thus allowing for machining via Electrical Discharge Machining (EDM) or its potential applications as pieces of tinder (igniter) in diesel engines or aerospace devises. In this study, Si۳N۴ powder was mixed with MoSi۲ (synthesized in the previous work through SHS) and additives such as MgO, CeO۲, and Y۲O۳ in varying percentages. Some of the mixed powders were milled using a SPEX ۸۰۰۰. All material powders were then formed into pellets using a uniaxial press. The pellets were then sintered in an atmosphere-controlled tube furnace in argon at a maximum temperature of ۱۵۰۰ °C with a soaking time of ۲ or ۳ hours through Pressureless Sintering (PLS) process. The sintered samples were analyzed at different stages: density measurements, phase and microstructure studies using XRD and SEM, and HV microhardness measurements. The results demonstrated that Si۳N۴-MoSi۲ structural porous composites were successfully prepared and optimized by controlled parameters such as pressing pressure, milling process, type and percentage of additives, and soaking times.

کلیدواژه ها:

Porous Composite ، Si۳N۴ ، MoSi۲ ، Additive ، Paritially Sintered