Preparation of α‐Si <sub/>3</sub> N <sub/>4</sub> by direct nitridation using the polysilicon waste by diamond wire cutting

摘要： With the rapid development of the semiconductor industry and solar photovoltaic industry, a large number of polysilicon wastes from diamond wire cutting are accumulated, which not only pollute the environment, but also cause safety problems due to the ultrafine particle size and high reactivity. The diamond wire cutting polysilicon waste was used to prepare α-Si3N4 by direct nitridation method. This method could not only fully recycle the waste and reduce environmental pollution, but also reduce the production cost of α-Si3N4. Furthermore, the effects of FeCl3, NaCl and metal Cu on the nitridation of polysilicon waste are investigated in detail, respectively. It is found that FeCl3 and NaCl are not ideal additives for the preparation of α-Si3N4. However, α-Si3N4 dominated Si3N4 can be obtained via adding 5 wt. % Cu after nitridation at 1250 oC for 8 h, and the relative content of α-Si3N4 reaches 92.37 %.