Compaction and Pressureless Sintering Characteristics of Silicon and a Silicon Composite Containing a Multicomponent Molybdenum Alloy Reinforcement

The compaction and sintering characteristics of silicon and a silicon composite containing a multi-component Molybdenum alloy (Mo44Si26Ta5Zr5Fe3Co12Y5) as reinforcement is reported here. Compaction with different binders viz zinc stearate, stearic acid and poly-vinyl alcohol (PVA) revealed that only PVA is suitable for making crack free pellets. Furthermore, silicon particles with angular shape were found to develop cracks during compaction compared to those bearing spherical shape. The compaction characteristics of Si and Si composites were evaluated using the Heckel’s approach and analysis of data revealed that round particles ensure better die filling. Pressureless sintering of the silicon and silicon composite compacts was carried out at 1225 °C for a duration of 12 h and intriguingly the relative density of the sintered compacts was found to be lower than respective green compacts. This was attributed to poor sintering tendency of silicon and also to the loss of the volatile organic binder.