Study On Corrosion Resistance Of WC-based Cemented Carbide

WC-based hard alloys play an important role in aerospace,precision molds,automotive parts,valves and other fields due to their strong mechanical properties such as high strength,high hardness,and high wear resistance.They ar e known as "industrial gears".At present,WC-based cemented carbides are used more and more widely in the field of coal chemical industry.In addition to requiring its excellent mechanical properties,it also has high requirements for its corrosion resistance.For the special application environment of coal chemical industry,it has become very important to explore the corrosion resistance of WC-based hard alloys under different media.In view of this,WC-Co hard alloy and WC-Ni hard alloy were prepared by vacuum sintering technology.The microstructure and phase of cemented carbide were analyzed by metallographic microscopy(OM),scanning electron microscopy(SEM),and X-ray diffraction(XRD);and the type of binder phase,the type and concentration of the corrosive medium,Corrosion resistance was tested and analyzed.Using vacuum sintering technology,WC-Ni cemented carbide with different Co bonded phases and WC-Co cemented carbide with different Ni bonded p hases were prepared.Metallographic microscope(OM)and scanning electron microscope(SEM)are used to analyze the microstructure of cemented carbide,X-ray diffraction(XRD)is used for phase analysis of cemented carbide;Putting WC-based cemented carbide in different corrosion solutions to observe the influence of soaking time on the performance of WC-based cemented carbide;Electrochemical workstation is used to test the electrochemical corrosion performance of WC-based cemented carbide,and to observe the corrosion resistance of the alloy in different media.The main findings are as follows:1.Through the analysis of the microstructure and phase composition of cemented carbide,it is concluded that the WC-based cemented carbide has a relatively pure structure and no phase appears to deteriorate the performance of the material.2.According to the immersion experiment results,the corrosion resistance of WC-Ni hard alloy is better than that of WC-Co hard alloy in sulfuric acid solution,The corrosion resistance relationship is WC-6Ni>WC-8Ni>WC-10Ni>WC-6Co> WC-8Co>WC-10 Co.In the sodium hydroxide solution,the corrosion resistance of WC-Ni cemented carbide is better than that of WC-Co cemented carbide.The corrosion resistance relationship is WC-6Ni>WC-8Ni>WC-10Ni>WC-10Co> WC-8Co>WC-6Co.In the sodium sulphate solution,the corrosion resistance of the WC-Ni hard alloy is better than that of the WC-Co hard alloy.The corrosion resistance relationship after is WC-8Ni>WC-6Ni>WC-10Ni>WC-8Co>WC-6Co> WC-10 Co.The corrosion resistance in sodium chloride solution is WC-6Ni>WC-8Ni>WC-6Co>WC-10Co>WC-10Ni>WC-8Co.3.According to the electrochemical experiment results,the corrosion resistance of WC-Ni hard alloy is better than that of WC-Co hard alloy.In the sulfuric acid solution,the corrosion resistance of the WC-based hard alloy decreases as the concentration of the solution increases.Corrosion resistance of WC-based hard alloys in both sodium hydroxide solution and sodium sulfate solution increases as the solution concentration increases.Corrosion resistance of WC-Co cemented carbide in sodium chloride solution: WC-6Co>WC-10Co>WC-8Co,corrosion resistance of WC-Ni cemented carbide: WC-6Ni>WC-8Ni>WC-10Ni...