【作者】 张欢；

【导师】 郭忠诚；

【作者基本信息】 昆明理工大学 ， 材料学， 2003， 硕士

【摘要】 本文研究了利用脉冲电源电沉积多元多功能复合镀层的工艺，获得了具有更优异的耐蚀、硬度、抗高温氧化和耐磨等性能的Ni-W-P-SiC、RE-Ni-W-P-SiC、RE-Ni-W-P-SiC-MoS₂和RE-Ni-W-P-PTFE等一系列的新型复合镀层、采用日本岛津EPMA-1600型电子探针、日本理学3015型X-射线衍射仪，光学显微镜、HX-1型显微硬度计、HDV-7晶体管恒电位仪、MM2000型磨损实验机和YWX-F型盐雾腐蚀试验箱等手段对各镀层的成分、性能和结构进行了测试。 根据热力学数据，绘制了298K下Ni-P-H₂O系电位-pH图，利用电位-pH图从热力学上分析电沉积Ni-W-P-SiC系列复合镀层的形成机理，并从脉冲电沉积的机理及其影响因素分析了脉冲复合电沉积的可行性。 试验研究了脉冲频率和占空比对Ni-W-P-SiC等四种复合镀层沉积速率和镀层成分的影响。不同的脉冲频率和占空比值使镀层沉积速率和镀层成分有很大的差异；在Ni-W-P-SiC和RE-Ni-W-P-SiC复合镀层的脉冲电沉积工艺中，当f=20～33Hz和r=0.4～0.8时，镀层的沉积速率较大；在RE-Ni-W-P-SiC-MoS₂和RE-Ni-W-P-SiC-PTFE复合电沉积工艺中，沉积速率在f=33Hz，r=0.8处最大；各种镀层中，Ni元素的含量最高，在RE-Ni-W-P-SiC-MoS₂和RE-Ni-W-P-SiC-PTFE镀层中，MoS₂和PTFE的含量很小，基本上都小于1％。 试验研究了四种脉冲复合镀层在耐蚀性、硬度、抗高温氧化和耐磨性等方面的异同，以及脉冲电沉积镀层和直流电沉积镀层在性能上的差异。四种脉冲镀层在HCl、H₂SO₄、H₃PO₄、FeCl₃中的耐蚀性优于不锈钢（1Cr18Ni9Ti）；脉冲镀层在腐蚀介质中的耐蚀性优于相应的直流镀层；除RE-Ni-W-P-SiC-PTFE脉冲复合镀层外，其余镀层在400℃热处理条件下的耐蚀性优于相应的镀态镀层；镀层在磷酸中的耐蚀性最好，在三氯化铁溶液中的耐蚀性最差；四种镀层的耐蚀性各有优劣，相对而言，Ni-W-P-SiC镀层具有较优异的耐蚀性。除RE-Ni-W-P-SiC-PTFE脉冲镀层外，其余三种脉冲复合镀层的硬度都比硬铬高；四种脉冲复合镀层在不同热处理温度下的硬度都比相应的直流镀层的硬度高；四种脉冲复合镀层中，RE-Ni-W-P-SiC镀层的硬度最高。四种脉冲复合镀层在镀态下的耐磨性都大大优于硬铬和相应的直流镀层；RE-Ni-W-P-SiC-MoS₂和RE-Ni-W-P-SiC-PTFE二脉冲镀层的耐磨性优于另外两种脉冲镀层。脉冲镀层的抗高温氧化性优于相应的直流镀层；Ni-W-P-SiC、RE-Ni-W-P-SiC二脉冲镀层具有更优异的抗高温氧化性。通过工昆明理工大学硕士学位论文摘要艺和性能研究，得出了各镀层性能较好时的脉冲参数。 采用浸泡实验、绘制阳极极化曲线和中性盐雾试验三种方法研究脉冲频率和占空比对Ni一W-P一SIC复合镀层耐蚀性的影响表明:当脉冲参数在卜33一50Hz，r=o.4一0.名的范围内时，Ni一W-P一siC复合镀层的耐蚀性较好。Ni一W-P一SIC脉冲复合镀层腐蚀后的表面形貌表明，镀层在HCI溶液中的腐蚀属于点蚀，在玩504、H3PO4和FeC13溶液中的腐蚀属于缝隙腐蚀。 对RE一Ni-V昨P一SIC脉冲复合镀层的硬度和抗高温氧化性研究表明:脉冲频率和占空比对镀层硬度和抗高温氧化性都有较大的影响。镀层获得较高硬度的脉冲条件为:f在SOHz左右，r在0.6一0.8之间;在卜33HZ，二0.4或拼0.6处镀层的抗高温氧化性较好。热处理温度和时间对各种脉冲参数条件下得到的镀层硬度和氧化增重率都有一定的影响，热处理温度在400一600℃范围内镀层获得较高的硬度，热处理温度小于800℃时，镀层的氧化增重不明显，但在大于800℃时，镀层增重迅速。 研究脉冲参数对RE书i一w-P一SIC一MoS:脉冲复合镀层耐磨性的影响得出:脉冲频率和占空比的大小对镀层的耐磨性有较大的影响，当脉冲参数为卜20一50Hz，二0.7时，RE，Ni-W^P一siC一MOS:脉冲复合镀层有较好的耐磨性。 对四种脉冲复合镀层的形貌和相结构研究表明:脉冲镀层表面比直流镀层光滑平整得多;脉冲镀层中的微粒比直流镀层中的微粒更多;脉冲电沉积工艺中，脉冲参数不同会得到表面平整程度和粒度不同的镀层。镀层截面的均匀程度从大到小依次为:RE一i一W-P一SIC一MoS:)RE一Ni一W-P一SIC一PTFE>RE一Ni一W-P一SIC>Ni一W-P。SIC。Ni一W-P一SIC、RE一Ni一W-P一SIC脉冲镀层在镀态时是非晶态结构，RE一Ni一W-P一siC一Mos:在镀态时是混晶结构，而RE一i一W-P一siC一PTFE脉冲镀层在镀态时是晶态结构;热处理温度对RE一Ni一W-P一SIC的相结构有较大的影响，随着热处理温度的升高和热处理时间的延长，镀层的非晶态逐渐减弱，镀层逐渐向晶态转变，并不断有新相的特征峰产生。 N卜W-P一SIC、RE一i一W-P一SIC、.RE一i一W-P一SIC一MoSZ、RE一Ni-W‘P一SIC一PTFE脉冲复合镀层具有较优异的性能，其中Ni一W-P一SIC脉冲镀层的耐蚀性最好，RE一Ni--W-P一siC脉冲镀层的硬度和抗高温氧化性最好，而RE一Ni一w-P一SIC一MoSZ和RE一Ni一W-P一SIC一PTFE具有优异的耐磨性。更多还原

【Abstract】 A series new Ni-W-P-SiC, RE-Ni-W-P-SiC, RE-Ni-W-P-SiC-MoS2 and RE-Ni-W-P-PTFE composite coatings with more excellent corrosion-resistance, hardness, oxidation-resistance and wear-resistance by pulse current were studied. The deposited composition, the properties and structure were tested by EPMA-1600 electron probe, 3015 X-ray diffraction patterns, optics microscope, HX-1 micro-hardness instrument, HDV-7 transistor permanent potential apparatus, MM2000 wear machine and YWX-F neutral salt-frog corrosion box, etc.The potential-pH diagram of Ni-P-H2O system at 298K was constructed by use of thermodynamic data. The formation mechanism of Ni-W-P-SiC system composite coatings was explained by means of potential-pH diagram, and the feasibility of pulse composite plating was analyzed by the mechanism and influence factors of pulse plating.The effects of pulse frequency and duty ratio values on the depositing rate and composition of the four composite coatings were studied and the results show that the influences were large. The depositing rate was high at f=20~33Hz, r=0. 4-0.8 in Ni-W-P-SiC and RE-Ni-W-P-SiC pulse electrodeposited processes; The depositing rate was high at f=33Hz, r=0.8 in RE-Ni-W-P-SiC-MoS2 and RE-Ni-W-P-SiC-PTFE electrodeposited processes. Content of Ni was highest in all coatings, Contents of MoS2 and PTFE were litter in RE-Ni-W-P-SiC-MoS2 and RE-Ni-W-P-SiC-PTFE composite coatings.The similarities and differences of the four composite coatings in corrosion-resistance, hardness, oxidation-resistance and wear-resistance and the divergences of properties between pulse deposited coatings and direct deposited coatings were studied. The corrosion-resistance of the four pulse deposited coatings was better than stainless steel(lCr18Ni9Ti) in HCl, H2SO4, H3PO4 and FeCl3 solutions; The deposited coatings by pulse current were better than that of by direct current in corrosion-resistance; The corrosion-resistance of composite coatings after heat-treatment at 400 C was better than plating coatings except RE-Ni-W-P-SiC-PTFE pulse deposited coatings; The corrosion-resistance of all pulse deposited coatings wasthe best in H3PO4 and the worst in FeCl3; Ni-W-P-SiC pulse composite coatings had better corrosion-resistance compared with the other three pulse composite coatings. The hardness of composite coatings was higher than hard chromium except RE-Ni-W-P-SiC-PTFE coatings; The deposited coatings by pulse current were better than that of by direct current in hardness; The hardness of RE-Ni-W-P-SiC composite coatings was the highest in the four pulse composite coatings. The hardness of the pulse composite coatings were much better than hard chromium and direct current coatings; The hardness of RE-Ni-W-P-SiC-MoS2 and RE-Ni-W-P-SiC-PTFE pulse composite coatings were better than the other pulse composite coatings. The oxidation-resistance of the pulse composite coatings were better than that of the direct current deposited coatings; Ni-W-P-SiC and RE-Ni-W-P-SiC pulse composite coatings had more better oxidation-resistance compared with the other composite coatings.The effects of pulse frequent and duty ratio value on corrosion-resistance of Ni-W-P-SiC composite coatings were studied by means of immerse experiments, drawing anodic polarization curves and neutral salt-frog corrosion test. The results indicated that Ni-W-P-SiC composite coatings had excellent corrosion-resistance at the range of f=33~50Hz, r=0.4~0.8. The surface morphologies of Ni-W-P-SiC composite coatings after corrosion indicated that the coating corrosion was dot corrosion in HC1 solution, but the coating corrosion were crack corrosion in H2SO4, H3PO4 and FeCl3 solutions.The studies on the hardness and oxidation-resistance of RE-Ni-W-P-SiC pulse current coatings indicated that pulse frequency and duty ratio value had a large influence on the hardness and oxidation-resistance. The coatings had high hardness at the range of f=50Hz, r=0.6~0.8 and the coatings had good oxidation-resistance at f=33Hz, r=0.4(or 0.6). Both heating temperature and he更多还原