化学镀Ni包覆TiC复合粉体的制备及显微组织  

Preparation and microstructure of Ni-coated TiC composite powder by electroless plating

作　　者：于鹏超[1] 易丹青[1,2] 胡彬[1] 刘会群[1] 

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]中南大学教育部有色金属材料科学与工程重点实验室,长沙410083

出　　处：《中国有色金属学报》2013年第2期439-447,共9页The Chinese Journal of Nonferrous Metals

基　　金：国家科技支撑计划项目(2011BAE09B03)

摘　　要：采用化学镀工艺,以联氨为还原剂制备纯Ni包覆的TiC复合粉体,并优化化学镀过程的工艺参数;采用DSC、XRD、SEM、EDS等测试方法对优化的工艺参数下制备的Ni包覆TiC粉体的表面形貌、形核长大机制和相组成进行分析。结果表明:当TiC装载量为10 g/L,施镀温度为70℃、pH=10、联氨浓度为100 mL/L时,可得到覆镀速度和镀层质量都比较高的镀层。在优化的工艺参数下,单位质量TiC上平均反应速率为0.013 g/min、平均覆镀量为0.8 g、反应时间约为60 min。TiC表面预处理后形成的台阶状区域成为Ni非均匀形核的活化区域。胞状Ni颗粒长大并彼此接壤后,形成均匀致密的Ni层。温度的变化强烈地影响着镀层的形貌,当施镀温度从70℃升高至95℃时,镀层从致密的胞状结构转变为疏松多孔的海绵状结构。化学镀后得到的Ni层为晶态和非晶态的混合体,经500℃保温1 h后,结晶完全。The Ni-coated TiC composite powder was prepared by electroless plating using hydrazine as the reductant, and the process parameters were optimized. The surface morphology, nucleation growth mechanism and phase component of the optimized TiC powders coated by pure nickel were studied using DSC, XRD, SEM and EDS. The results show that a better and faster formed coating can be obtained when the TiC powder load is 10 g/L, the plating temperature is 70 ℃, pH=10 and the hydrazine concentration is 100 mL/L. The mean reaction speed and plating per unit mass TiC are 0.013 g/min and 0.8 g, respectively, and the reaction time is about 60 rain. The heterogeneous nucleation of nickel occurs in the bench-shape area which forms in the surface pretreatment. The cellular Ni particles grow up and form uniform and compact nickel coating finally. The temperature variation strongly affects the morphology of the coating. The coating turns to loose porous spongiform structure from compact cellular when the plating temperature varies from 70 ℃ to 95 ℃. The obtained nickel coating turns out to be the association of crystalline and amorphous, and is crystallized completely after heat preservation at 500 ℃ for 1 h.

关 键 词：化学镀 Ni包覆TiC复合粉末 显微组织 形核长大机制 

分 类 号：TQ153.3[化学工程—电化学工业]