合金元素对氮化硅制备的影响与研究

【作者】 葛伟萍；

【导师】 赵昆渝；

【作者基本信息】 昆明理工大学 ， 材料学， 2003， 硕士

【摘要】 本课题以硅粉为原料，合金元素为添加剂，用硅粉直接氮化法制备氮化硅，并对添加剂种类及含量、氮化工艺等进行研究，并对氮化硅的形成机制和部分添加剂的作用进行了探讨。 在Fe、Mg、Al、Ti四种合金元素添加剂中，Fe对硅粉氮化促进效果最显著，Mg次之，而Ti、Al不太明显。但Al对β-Si₃N₄生成有一定的促进作用。 复合元素Fe+Al又比单一元素Fe的氮化促进效果更优。从生成单一氮化硅的角度来看，Fe含量不宜超过1％，Fe+Al不宜超过1.5％，反之产物中就出现Fe-Si化合物。 实验氮化工艺控制在1350℃下连续氮化10小时，以Fe和Fe+Al为添加剂，这对硅粉氮化有利。 采用X射线衍射（XRD）、扫描电镜（SEM）等测试手段对样品的相组成和微观组织形貌进行了观察和分析，表明1350℃／10h下的氮化样品中生成物以α-Si₃N₄较多，还有部分β-Si₃N₄。产物组织形貌以等轴状的α-Si₃N₄颗粒为主，颗粒平均尺寸为3.3μm。更多还原

【Abstract】 With Si powders as raw materials, alloy elements as additives, silicon nitride was prepared through the direct nitridation of Si powders. Categories and content of the additives and nitriding process were researched. The Synthesis mechanism of silicon nitride and function mechanism of some additives in the reaction were primarily studied.It is found that Fe promotes the nitridation best in the four additives of Fe, Mg, Al, Ti. Then Mg is second, Ti, Al is not that obvious for the nitridation. But Al accelerates the growth of β -Si3N4 to a certain extent.Composite elements Fe+Al enhances the nitridation better than Fe. But in order to gain pure silicon nitride, the contents of Fe+AI and Fe should be contained within 1% and 1.5% respectively, otherwise the compound of Fe-Si will appear in the products.The nitriding process of this experiment selected a reaction time of 10 hours at 1350 C, together with Fe and Fe + Al elements as additives. Only this is benefit to the nitridation of silicon powders.The composition of nitrided products, microstructure and morphology of reaction samples were studied by X-ray Diffraction (XRD) and Scan. Electron Microscope (SEM) . The results show that Si3N4 with high a phase and some P phase can be prepared under the nitriding conditions of 1350 C/10h. The microstructure of nitrided products is characterized by α -Si3N4 grain shape. The average grain size is 3.3 m.更多还原