非晶态Ni-W/ZrO_2复合镀层的制备、热处理及腐蚀行为

Preparation,Heat Treatment and Corrosion Behavior of Amorphous Ni-W/ZrO_2 Composite Coating

在镍钨合金电解液中,通过搅拌使二氧化锆固体微粒悬浮,电沉积制备Ni-W/ZrO2复合镀层.研究结果表明,二氧化锆粒子影响复合镀层的电沉积、表面形貌、结构、热处理过程和抗腐蚀性能;与Ni-W合金的电沉积过程相比,复合镀层中的W含量和电流效率均降低;在400℃处理1h后,嵌入Ni-W本体中的ZrO2粒子脱落,W向镀层表面富集.扫描电子显微镜(SEM)结果显示,复合镀层呈现团粒状形态,无裂纹.差示扫描量热(DSC)分析结合X射线(XRD)衍射实验指出,Ni-W/ZrO2复合镀层为非晶态结构.复合镀层的显微硬度较纳米晶Ni-W合金的高;热处理后,复合镀层的显微硬度和在3%氯化钠溶液中的抗腐蚀行为显著增强.

A Ni-W/ZrO2 composite coating was prepared by electrodeposition from a Ni-W bath containing zirconia solid particles suspended in an electrolyte solution by stirring. Results showed that the presence of zirconia particles influenced the electrodeposition, surface morphology, crystallographic structure, thermal treatment and corrosion resistance of the obtained composite coating. By comparison to Ni-W alloy electrodeposition both W content in the Ni-W matrix and deposition current efficiency for the composite coating decreased. After heat treatment at 400 ℃ for 1 h some embedded zirconia particles were removed from the Ni-W matrix and W was enriched at the top surface of the deposit. Scanning electron microscopy （SEM） results revealed that the composite coating had a granular morphology and was crack-free. A differential scanning calorimetry （DSC） experiment combined with X-ray diffractometry （XRD） indicated that the Ni-W/ZrO2 composite coating was amorphous. The microhardness of the composite coating was higher than that of the nanocrystalline Ni-W alloy. After heat treatment of the composite coating its microhardness and corrosion resistance in 3% NaCl solution were greatly enhanced.