Study on the process of the CoNiCrAlY bonding layer under laser shock

Abstract

In this study, atmospheric plasma spraying was used for the preparation of a CoNiCrAlY bonding layer on a nickel (Ni)-based superalloy with different laser shock times designed for surface modification. In addition, electron-beam physical vapor deposition was used to deposit a ceramic layer to form a new modified coating. When comparing high-temperature oxidation resistance with mechanical properties for both traditional coatings and modified coatings as well as the effects of different laser shock times on them, the results showed that the cross-section hardness of the coating under two laser shocks reaches the peak value of 297 HV, which is 11% higher than that of ordinary coating. The growth rate of the thermal growth oxide at the interface of the modified coatings is significantly lower than that of the ordinary coating under different oxidation times at 1000°C. Furthermore, the lowest rate, 2·43 × 10−4 μm/h, occurs after being laser-shocked twice. With the increase in oxidation time, the residual compressive stress generated during the oxidation increases first and then decreases. Moreover, the stress value of the modified coating after being laser-shocked twice is the smallest. To conclude, this research is of significance for application in surface modification for aviation.