镍基纳米碳管/二氧化钛复合镀层的制备及性能

Preparation and properties of nickel matrix carbon nanotubes/titanium dioxide composite coating

为了改善金属基材的表面性能,以钛铁矿为原料,利用微波等离子体化学气相沉积法制备了纳米碳管/二氧化钛复合粉体.采用复合电泳电沉积法在不锈钢基体表面制备了镍基纳米碳管/二氧化钛复合镀层;利用扫描电镜、X射线衍射仪、数显维氏硬度计和电化学测试等手段研究了纳米碳管/二氧化钛复合粉体对复合镀层结构和性能的影响.结果表明纳米碳管/二氧化钛复合粉体的加入有效地减小了复合镀层中镍的晶粒尺寸,促进了金属镍沿(111)晶面择优取向生长,改变了镍的电沉积层结构,提高了镀层的硬度,改善了镀层的耐腐蚀性能;在复合粉体的作用下,复合镀层的硬度与纯镍镀层相比提高了110%,腐蚀电位正移了23mV,腐蚀电流密度减少了0.991微安/平方厘米.

To boost the surface properties of metal,carbon nanotubes（CNTs）/titanium dioxide（TiO2） composite powders were synthesized by microwave plasma chemical vapor deposition.Carbon nanotubes/titanium dioxide enhanced nickel matrix composite coating was grown on the stainless steel by electrodeposition.The effects of the CNTs/TiO2 composite powders on the properties of composite coating were investigated with methods of scanning electron microscopy（SEM）,X-ray diffractometry（XRD）,hardness testing and electrochemical testing.The results show that the addition of carbon nanotubes/titanium dioxide composite powders decreases the grain size of Ni crystal effectively,and leads to nickel crystal growing preferentially along（111）crystal face orientation,which transforms nickel electrodepisition strucrures to form resulting improved hardness and corrosion resistance coating;comparing to pure nickel coating,the hardness of composite coating increases by 110%,corrosion potential shifts 23 mV positively and corrosive current intensity decreases by 0.991 microamp per square centimeter.