Combustion Synthesis of Powders for Advanced Ceramic Materials

精细、超纯、球形颗粒是理想的起始原料， 生产高性能先进陶瓷的材料 产品. AeroChem拥有独特的火焰合成工艺， 制备这种高质量的粉末， 氮化物 这一过程不同于通常的燃烧 在不使用氧气的情况下进行合成： 反应物也支持火焰。 对于氮化硅， 硅烷、氨、肼和氮在平板上燃烧 火焰燃烧器 生产出高质量的粉末， 样品，没有添加剂，成功地进行了热处理， 等静压 然而，肼的使用使得 该方法由于成本而在商业上不可接受， 肼的爆炸性和毒性。 而 热力学和其它考虑表明，氨 应该支持没有肼存在的火焰，我们没有 没有联氨也能工作 计算机 提出了建模研究，以了解为什么 氨/硅烷系统不支持火焰下 已使用的条件，并定义 火焰可以被支撑的条件。 然后将进行实验以确定实际的 在规定条件下运行的可行性。 该计划的成功完成将使 先进的陶瓷制造业提供了比现有技术更高质量的粉末， 目前可用。 拟议研究的最终产品将是一个 制备高质量的 用于高级陶瓷的氮化硅粉末。 本 先进陶瓷的发展受到了以下限制： 美国制造的高品质粉末。

Fine, ultrapure, spherical particles are desirable starting materials for producing high performance afvanced ceramic products. AeroChem has a unique flame synthesis process for preparing such high quality powders, including silicon nitride. This process differs from the usual combustion synthesis in that no oxygen is used: the particle-producing reactants also support the flame. For silicon nitride, silane, ammonia, hydrazine, and nitrogen are burned on a flat flame burner. A high quality powder is produced of which a sample, without additives, was successfully subjected to hot isostatic pressing. However, the use of hydrazine makes the process commercially unacceptable because of the cost, explosive nature, and toxicity of hydrazine. While thermodynamic and other considerations indicate that ammonia should support a flame without hydrazine present, we have not been able to operate without some hydrazine. A computer modeling study is proposed to understand why the ammonia/silane system does not support a flame under the conditions which have been employed, and to define the conditions under which a flame could be supported. Experiments will then be performed to determine the practical feasibility of operating under the defined conditions. Successful completion of this program would make available for advanced ceramic manufacture a higher quality powder than is currently available. The final product of the proposed research would be an economical process for the preparation of a high quality silicon nitride powder for use in advanced ceramics. Present progress in advanced ceramics is limited by the unavailability of a US made high quality powder.