Study On Preparation And Properties Of Wear Resistance Layer Of Servo Valve Feedback Rod

Affect the reliability and stability of precision mechanical parts during use due to surface wear.As the core component of the servo valve,the spool receiving groove and the feedback rod ball head easily form a gap due to wear during high frequency conversion,which greatly reduces the feedback accuracy of the servo valve feedback lever.In order to improve the wear resistance of the servo valve ball tip surface,The experiment uses Tungsten Carbide(WC)as a modified material?and preparation of WC films by pulsed magnetron sputtering.Study the influence of WC on the wear resistance of servo valve feedback rod surface.The experiment was carried out in three aspects.Firstly,Study the influence of target source on WC films;Secondly,study the influence of bias power source on WC films;Finally,study the influence of Ar/C2H2 gas flow ratio on WC films.The experiment uses target current intensity(I),substrate negative bias(SVb),duty ratio(δN)and Ar/C2H2 gas flow ratio as experimental process parameters.The film deposition rate,surface morphology,structural composition,hardness and friction and wear were characterized by film thickness gauge,AFM,XRD,micro-hardness tester and high temperature friction and wear tester.The experimental results show,(1)As the intensity of the target current increases,the growth rate of the WC films layer gradually increases;If the effective discharge pulse is increased when the substrate has a negative bias Svb=125V,The deposition rate of the WC films increases first and then decreases,and the WC films deposition rate tends to decrease when 8N-70%.(2)Through the performance comparison at the target current intensity,it is found that when I=8A,the WC films has the best comprehensive performance,the hardness is up to 1158.37 HV,and the friction coefficient is 0.491;Through the performance comparison at the negative bias of the substrate,it is found that when SVb=75V,the WC films has the best comprehensive performance,the hardness is up to 1132HV,and the friction coefficient is 0.450.Through the performance comparison at the Ar/C2H2 gas flow ratio.When the Ar/C2H2gas flow ratio is 6:1,the hardness of the WC films is up to 1171.23 HV and the friction coefficient is 0.436.When the Ar/C2H2 gas flow ratio is 1:1,the WC films has a friction coefficient of the least 0.295 and a hardness of 940.53 HV;The overall comprehensive performance comparison found that the substrate negative bias and the acetylene gas can improve the wear resistance of the WC films.