Effects of Temperature and Si3N4 Diluent on Nitriding of Diamond Wire Silicon Cutting Waste

The effects of temperature and Si3N4 diluent on nitriding of diamond wire silicon cutting waste were studied in detail. The phase contents and microstructures of nitriding products were detected using X-ray diffraction and scanning electron microscopy. Moreover, the thermogravimetric and differential thermal analysis were used to investigate weight changes and heat flow changes of the samples in the heating-up stage. The results suggested that during the nitriding of cutting waste, the Si3N4 diluent as heat acceptor can absorb the additional heat released from the reaction between silicon and nitrogen, hindering the formation of the liquid phase, thereby improving the overall conversion and promoting the formation of α-Si3N4. It was also revealed that high temperatures can promote the formation of β-Si3N4. This is because α-Si3N4 is a low-temperature metastable phase and β-Si3N4 is a high-temperature stable phase, α phase can be transformed to β phase at high temperatures. Besides, nitriding mechanisms and effects of temperature and Si3N4 diluent on nitriding of the cutting waste were discussed.