Morphologies And Properties Of Ni-W-P Based Antifriction And Wear-resistant Composite Plating By Electro-deposition

Electro-deposition is a commonly used surface engineering technology,and it is widely used in the fields of daily production,manufacture and repair.Traditional electroplating process firstly appeared in the electroplating chromium and its alloys,and the coating has excellent wear resistance,corrosion resistance,practicality and aesthetics.But the defects of the traditional plating process is obvious because the manufacturing process will cause a lot of pollution and the chromium-containing wastewater is carcinogenic.Therefore,in recent years,traditional plating has been gradually withdrawn from the utility industry.Ni-based alloy coating has excellent comprehensive performance that can not only rival chromium plating process,but also avoid serious pollution.So it has received extensive research and attention.Ni-W-P coating is one of the Ni-based coatings which owns good wear resistance and corrosion resistance and is expected to substitute Chromium coating.In this paper,Ni-W-P coating has been prepared by the method of electro deposition,and then added nano-particles,SiC and PTFE to the deposit co-deposition,in order to prepare Ni-W-P based antifriction and wear of composite coating.The structure and composition of the coating has been analyzed by means of metal graphic microscope,scanning electron microscope?SEM?,differential thermal analyzer?DTA?,X ray diffraction?XRD?,energy dispersive spectroscopy?EDS?.The property of the coating has been studied by a series of experiments including micro hardness,friction and wear properties and electrochemical corrosion.Research shows that the process parameters of the preparation of high quality Ni-W-P coatings is Na₂WO₄ 60g/L,NiSO₄ 50g/L,Na H₂PO₂ 20g/L,Na₃C₆H₅O₇ 80g/L,current density 4A/dm2,p H 7⁸,time 3h,temperature 70?.On this basis,nano SiC,PTFE powder and FC-4 has been added as a dispersant and ultrasonic dispersion.the process parameters of the preparation of high quality Ni-W-P-SiC-PTFE coatings is Na₂WO₄75g/L,NiSO₄ 80g/L,NaH₂PO220g/L,Na₃C₆H₅O₇100g/L,SiC2g/L,PTFE10mL/L,current density 4A/dm2,pH7⁸,time3 h,temperature 70?.The results of EDS analysis shows that the weight percentage of Ni-W-P coating under the condition of different parameters of Ni is 58.23%,less than W and P,also the percentage of weight of F and Si reflected in the coating;the results of XRD shows that the Ni-W-P coating is amorphous or mixed crystal Ni-W-P coating;550? heat treatment can make the coating obvious crystallization,precipitation Ni-P and Ni-W second phase.After adding SiC and PTFE nano powders,surface roughness of composite coating increased,and the metallic luster is not obvious,the result of DTA shows that the crystallization temperature of heat treatment is in advance,and will also lead to obvious crystallization,precipitation of Ni-P and Ni-W complex phase.Due to the hard phase of nano SiC particles,the hardness of the composite coatings increased significantly,and the wear resistance,corrosion resistance are also increased.In the presence of PTFE in the coating,reduce the efficient of friction,the coating has a certain effect of lubrication and friction reducing.The Ni-W-P-SiC-PTFE composite coating heat treatment at high temperature corrosion potential increased,the corrosion resistance will be significantly improved)Will decline,but after heat treatment at high temperature and corrosion resistance will be improved obviously.