Effect of Power on Microstructure and Hot Corrosion of Induction-Assisted Ultra-High-Speed Ni60 Laser Cladding
摘要
The Ni60 coating was fabricated by inductively heated assisted extreme high-speed laser cladding (EH-LIHC) technology, and its surface morphology, microstructure and hot corrosion resistance were studied systematically. The results show that the number of cracks increased with the increase in laser power. The crack-free Ni60 coating was fabricated when the laser power was 3900 W. The cladding layer develops from planar crystals to columnar crystals and dendrites. With the increase in laser power, the dendrites of cladding layer become coarse, and the dilution rate of coating elements increases. After hot corrosion at 700 °C and 900 °C for 60 h, the mass gain of traditional laser cladding (CLA) samples was 150.5 mg/cm2 and 450.5 mg/cm2, respectively. The mass gains of EH-LIHC-3, EH-LIHC-2 and EH-LIHC-1 samples were 132.6 mg/cm2, 124.1 mg/cm2, 116.7 mg/cm2, 380.4 mg/cm2, 360.5 mg/cm2 and 340.1 mg/cm2, respectively. They were 88.1%, 82.5%, 77.5%, 84.4%, 80.0% and 75.5% of CLA samples, respectively. The high-temperature hot corrosion resistance of EH-LIHC samples is better than that of CLA samples. Therefore, using EH-LIHC can successfully fabricate Ni60 samples with no holes, no cracks and good hot corrosion-resistant properties.