《前躯体碳化法制备钠米碳化铬粉末》》-毕业论文.doc

PAGE 毕业论文 题 目:　　 前驱体碳化法制备纳米碳化铬粉末　　　 　　　　　　　　　　　　　　　　　　 　　　　　 　　　　　　　　 　　院系名称：材料科学与工程 专业班级： 材料升0801 　　学生姓名： 学 号： 指导教师： 教师职称： 讲师 年 5 月 28 摘 要 碳化铬具有较高的熔点、硬度和高温强度，以及良好的电导率和热导率。这些优异的性能确保了其在冶金、电子、催化剂和高温涂层材料等方面的广泛应用。 本课题选用重铬酸铵和纳米碳黑为原料，先将原料制成前驱体粉末，再在真空碳管炉中进行碳热还原反应，在一定条件下制备成纳米碳化铬粉体。主要采用了XRD、SEM等分析手段研究了不同工艺条件（反应温度、保温时间、配碳量）对制备纳米碳化铬的影响。 通过实验得出以下结论：900℃时，反应产物中主相为Cr2O3，含有少量的Cr3C2和游离碳。1000℃时，Cr2O3的量减少，Cr3C2的量增多。1100℃时，碳含量为19%、21%时，保温时间在30min、60min、90min时，反应产物均为单一的Cr3C2。900℃时反应产物颗粒基本呈球形或类球形，有少量的团聚现象，这主要由于该温度条件下正发生Cr2O3向Cr3C2的相转变，造成部分颗粒团聚。1000℃时反应产物颗粒尺寸在45-55nm之间变化，并且团聚现象减少，反应产物中Cr3C2生成量增多。1100℃时反应产物颗粒呈球形或类球形，无明显团聚现象，颗粒尺寸在30-40nm之间。 关键词：碳化铬 纳米碳黑 碳热还原法 重铬酸铵  Title The preparation of chromic carbide nanopowder by precursor carbonization method Abstract Chromium carbide has a high melting point, hardness and high temperature strength and good electrical conductivity and thermal conductivity. The excellent performance ensure that it is widely used in metallurgy, electronics, catalysts and high-temperature coating materials. Ammonium dichromate and nano-carbon black were used as raw materials, and were prepared as precursor powder firstly, then in a vacuum carbon tube furnace for carbothermal reduction. Under certain conditions, chromium carbide nanopowder was obtained. Effects of different process conditions (temperature, holding time, carbon content) on the preparation of chromium carbide nanopowders by using XRD and SEM methods. The experiment shows the following conclusions: at 900 ℃, the main phase of the reaction products was Cr2O3, containing a small amount of Cr3C2 and free carbon. At 1000 ℃, the mount of Cr2O3 reduced, while the mount of Cr3C2 increased. At 1100 ℃, the carbon content was 19% and 21%, when the holding time was at 30min, 60min, 90min, the reaction products are single Cr3C2. At 900 ℃ the reaction products was basic spherical particles or spherical with a small amount