【作者】 郑华明；

【导师】 黄新民；

【作者基本信息】 合肥工业大学 ， 材料学， 2010， 硕士

【摘要】 本文采用电沉积方法制备Ni-W-P-SiC多元复合镀层。通过正交试验方法和单因素试验研究了不同工艺参数对复合镀层性能的影响,研究了沉积液组成和工艺条件对Ni-W-P-SiC复合镀层成分、组织结构、表面形貌、摩擦磨损以及耐腐蚀性能的影响。利用金相显微镜、扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)对镀层的形貌、组织结构和成分进行分析,并通过显微硬度测试、摩擦磨损试验、电化学试验测试了镀层的力学性能、摩擦磨损性能和耐腐蚀性能。实验得到最佳复合镀液组成和工艺条件为：Na2WO4’2H2O:50g/l, NiSO46H2O:50g/l,C6H8O7H2O:50g/l,NaH2PO2’H2O:10g/l,SiC:40g/l,表面活性剂OP-10:0.6 g/l,pH:7,T:50℃,Dk:4A/d m2,搅拌速度：200 r/min.在优化条件下制备的Ni-W-P-SiC复合镀层,具有较好的性能和组织结构。采用XRD分析镀态镀层的物相主要是非晶态；在400℃热处理后镀层主要为晶态物相：Ni.Ni3P.SiC.Ni5P2；采用EDS分析优化条件下获得的复合镀层的重量百分比为：Ni：78.44wt%,W：7.11wt%,P：11.45wt%,C：1.31wt%,Si：1.69wt%。Ni-W-P-SiC复合镀层具备较高的显微硬度和耐磨性。当SiC微粒添加量为60 g／l时,硬度和耐磨性能达到最高;随着热处理温度的升高,复合镀层硬度增加,在400℃热处理3小时显微硬度达到峰值1050HV。Ni-W-P-SiC复合镀层的耐蚀性优于Ni-W-P镀层和钢基体,当SiC添加量为60g/1时,复合镀层的耐蚀性能最佳。热处理后复合镀层的耐蚀性比镀态镀层显著提高,热处理温度为400℃时,耐蚀性能最佳。Ni-SiC.Ni-W-P.Ni-W-P-SiC的表面形貌差别不大,都为典型的胞状组织；在Ni-SiC和Ni-W-P-SiC复合镀层中,SiC颗粒弥散镶嵌于基体中。Ni-SiC镀层只存在Ni和SiC两种物质,且不存在晶态的变化；而Ni-W-P和Ni-W-P-SiC镀层的晶态会随温度的变化而转变,并有新相的析出,能明显强化Ni-W-P-SiC复合镀层的显微硬度。Ni-W-P-SiC复合镀层的耐磨性能和耐蚀性能优于Ni-W-P合金镀层和Ni-SiC镀层。更多还原

【Abstract】 Ni-W-P-SiC composite coatings were prepared by electrodeposition. The influence parameters on the composite coatings were researched by orthogonal test method and single factor analysis method. The faults such as bath composition and operating condition on the composition, microstructure, morphology, wear & friction and corrosion resistance of Ni-W-P-SiC coatings were investigated. The metallurgical microscope,scanning electron microscope(SEM),transmission electron microscope(TEM) and X-ray diffraction(XRD) were used to analysed the morphology, microstructure and composition of Ni-W-P-SiC composite coatings. The microhardness, friction wear and electrochemistry experiment were performed to analyse the mechanical, friction,wear behavior and corrosion resistance properties.The optimal electrodeposition conditions were:Na2WO4·2H2O:50g/l, NiSO4·6H2O:50g/l, C6H8O7·H2O:50g/l, NaH2PO2·H2O:10g/l, SiC:40g/l, OP-10:0.6g/l, pH:7,T:50℃,Dk:4A/d m2,stirring speed:200 r/min.The XRD show that the as-deposited composite coating has an amorphous form and transforms to crystalline after heat treatment at 400℃with the phases of Ni、SiC、Ni3P and Ni5P2.The content of the component analyzed by EDS was:Ni:78.44wt%, W:7.11wt%,P:11.45wt%,C:1.31wt%,Si:1.69wt%.The hardness and wear resistance of the Ni-W-P-SiC composite coating depends on the SiC content,and reach the best status at the content of 60g/l.(?) The coating has the highest hardness of about 1054HV when heat treated at 400℃for 3 hours.The corrosion resistance of Ni-W-P-SiC composite coatings is better than Ni-W-P coatings and steel substrate, and reachs the best corrosion resistance when the SiC addition is 60g/l. The corrosion resistance increases after heat treatment and has optimal performance when heat treated at 400℃.Ni-SiC、Ni-W-P、Ni-W-P-SiC coatings have little difference surface in morphology, and all have a typical cellular’structure; In Ni-SiC and Ni-W-P-SiC composite coating, SiC particle dispersion embedded in matrix. Ni-SiC coating exists only Ni and SiC two substances without crystalline changes. While in Ni-W-P and Ni-W-P-SiC coatings,crystalline changes with temperature changes and has new precipitation which can obviously enhance hardness of Ni-W-P-SiC composite coating.The wear resistance and corrosion resistance of Ni-W-P-SiC composite coating is better than Ni-W-P and Ni-SiC coating.更多还原