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Effects of defects and element diffusion at coating/substrate interface on damping capacity

In this work, the effects of the microstructures at the coating/substrate interface and in coating on damping and dynamic modulus by using low pressure plasma spray process and electro‐deposition (ELD) technology to deposit the Ni coating onto the Cu substrate were studied, and also research was conducted to explore the influence of elements diffusion on damping after ELD Ni/Cu coating system was heat treated. The microstructure of the coating system was observed using a scanning electron microscopy (CS3400) with an energy dispersive X‐ray spectrometer. The dynamic mechanical properties were tested using a dynamic mechanical thermal analyzer IV. The results indicated that there was a negative correlation between the modulus and the damping capacity for a coating structure. The difference between the damping values of the low pressure plasma spray coating system with more defects and ELD coating systems with few defects approximately equals to the damping value produced by defects. Defect can affect the value of pure damping peak (high temperature background damping subtracted) at around 150 °C. The higher the defect rate was, the higher the value of pure damping peak was. Elements diffusion at interface could change the amplitude and temperature of damping peak. Copyright © 2015 John Wiley & Sons, Ltd.