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1、·摘要化学镀Ni-W-P镀层具备硬度高、镀层厚度均匀、耐蚀性且耐磨性好等优势,于是,制备优质的镍钨合金镀层近年来成为世界各国的钻研的热门。实验采用化学镀法制备了Ni-W-P合金镀层,用SEM、XRD、电化学、点滴实验、硬度等测试手段对其性能进行表征。在钢铁表面制备了Ni-W-P合金镀层。研究了钨酸钠、硫酸镍、次磷酸钠、乳酸、温度等工艺参数对化学镀镍层沉积速度、点滴时间、电化学性能等的影响,通过正交实验优化出了化学镀Ni-W-P合金镀层的较佳工艺配方:35g·L–1硫酸镍,15g·L–1钨酸钠,35
2、g·L–1次亚磷酸钠,30g·L–1硫酸铵,32g·L–1柠檬酸钠,8g·L–1苹果酸,15ml·L–1乳酸,2-5mg·L–1碘酸钾,1mg·L–1硫脲,镀液pH值为4.8-5.1,温度为88℃。制备的Ni-W-P合金镀层结构呈现典型的高磷非晶态,其磷含量达11.1%。Ni-W-P合金镀层点滴时间为70s,耐蚀性略低于Ni-P镀层的76s,但其硬度为679.18HV,较镍磷合金镀层(562.14HV)和基体(268.1HV)分别提高了约117.4HV和411.08HV。结合力测试结果发现Ni-W
3、-P合金镀层的结合力强于Ni-P镀层。对制备的Ni-W-P合金镀层进行热处理。研究了200—800℃下热处理对镀层性能的影响,结果表明随着热处理温度的升高,镀层由非晶态逐步转化成为晶态,硬度呈现先增大后减小的趋势。当温度达到400℃时,衍射峰增强,镀层的胞状物边缘变得模糊,镀层的硬度值最大为1070.1HV,磨损量最小为5.3mg。化学镀Ni-W-P合金镀液的使用寿命。采用补加方法测出镀液的循环寿命为5MTO,在使用周期内镀液的沉积速度稳定在11µm·h-1以上,镀态硬度在670HV左右。关键词:
4、化学镀;Ni-W-P镀层;镀速;耐蚀性······ABSTRACTElectrolessNi-W-Palloyplatingshavemanyadvantagessuchasgoodwearresistance,corrosionresistance,filmthicknessuniformity,highhardnessandsoon.Andhence,preparinggoodperformanceofNi-W-Palloycoatingbecomesahottopicinrecentyear
5、sathomeandabroad.Inthisexperiment,theperformancesofNi-W-Palloycoatingpreparedonstainlesssteelsubstratehavebeentestedbyaseriesofmethodssuchasdriptest,thedepositionrate,micro-hardness,electrochemistry,scanningelectronmicroscopyandsoon.ElectrolessNi-W-Pa
6、lloycoatingswerepreparedonstainlesssteel.Thesodiumtungstate,nickelsulfate,sodiumhypophosphite,lacticacid,temperatureandotherprocessparameterswerestudiedonthedepositionrateofelectrolessnickelplatinglayer,theinfluenceofthebittime,theelectrochemicalprope
7、rties,etc.Theoptimumformulaacquiredbycombingwiththesinglefactorandorthogonalexperimentmethodareasfollowing:nickelsulfate35g·L-1,sodiumtungstate15g·L-1,hypophosphite35g·L-1,ammoniumsulfate30g·L-1,sodiumcitrate32g·L-1,malicacid8g·L-1,lacticacid15ml·L-1,
8、potassiumiodate2-5mg·L-1,thiourea1mg·L-1,pH4.8to5.1,temperature88℃,time1.5h.ThestructureofNi-W-PalloyplatingistypicalcrystallinestatewithhighcontentofPelement(11.9%).TheresultsshowedthatthecorrosionrisistanceofNi-W-Palloyplating(driptime70s)is