Effect of cold sprayed processing parameters on microstructure and fretting wear performance of CuNiIn coating

CuNiIn coatings are prepared on the surface of TC4 titanium alloy using cold spray technology， and the effects of gas types （helium， nitrogen） and preheating temperatures （500， 700 ℃） on the microstructure， microhardness， bonding strength， and gas fretting wear performance of the coatings are investigated. The results show that under the same gas preheating temperature， the porosity of coatings sprayed with helium is lower than that of coatings sprayed with nitrogen， and microhardness， bonding strength， and wear resistance are all superior to those of coatings sprayed with nitrogen. When the gas preheating temperature increases from 500 ℃ to 700 ℃， the porosity of the coatings sprayed with both gases decreases significantly （helium： from 1.4% to 0.05%， nitrogen： from 1.7% to 0.5%）. The hardness of coatings sprayed with helium increases from 213HV to 292HV， while that of coatings sprayed with nitrogen decreases from 275HV to 237HV. The increase in gas preheating temperature has no significant effect on the bonding strength of the coatings， but the type of gas has a significant effect on the bonding strength of the coatings， the average bonding strength of sprayed coatings with helium （70 MPa） is 30 MPa higher than that of sprayed coatings with nitrogen （40 MPa）. The wear rate of coatings sprayed with helium and coatings sprayed with nitrogen decreases with the increase of gas preheating temperature （helium： from 1.8% to 1.41%， nitrogen： from 2.21% to 1.51%）. With the increase of fretting displacement amplitude， the wear form of the coatings under optimized parameters changes from adhesive wear to abrasive wear.