Fig. 1. SEM image of Co-based powder

Fig. 2. Experimental apparatus of ultrasonic vibration

Fig. 3. Cross-sectional appearances of laser cladding layers under different conditions. (a) Without assistance of ultrasonic vibration; (b) with assistance of ultrasonic vibration

Fig. 4. Cross-sectional microstructures of laser cladding layers under different conditions. (a1)(a2)(a3) Without assistance of ultrasonic vibration;(b1)(b2)(b3) with assistance of ultrasonic vibration

Fig. 5. Oxidation dynamics of substrate and cladding layers with and without assistance of ultrasonic vibration. (a) Oxidation dynamic curves; (b) (Δm)2 versus oxidation time; (c) double logarithmic curves

Fig. 6. XRD patterns of Co-based laser cladding layers under different conditions. (a) Without assistance of ultrasonic vibration; (b) with assistance of ultrasonic vibration

Fig. 7. SEM images at surfaces of laser cladding layers after high-temperature oxidation under different conditions. (a1)(a2) Without assistance of ultrasonic vibration; (b1)(b2) with assistance of ultrasonic vibration

Fig. 8. Cross-sectional appearances of oxidation films of laser cladding layers under different conditions. (a1)(a2) Without assistance of ultrasonic vibration; (b1)(b2) with assistance of ultrasonic vibration

Fig. 9. Distribution of Cr in near surface of cladding layer. (a) Without assistance of ultrasonic vibration; (b) with assistance of ultrasonic vibration