Abstract:
Zirconium (Zr) and its alloys are the preferred materials for nuclear fuel cladding due to their low neutron absorption cross-section, among other advantages. However, the harsh service environment inside nuclear reactors, characterized by high temperature, high pressure, intense radiation, and wear, significantly shortens the lifespan of zirconium alloy components. Chromium (Cr), known for its excellent wear and corrosion resistance, is often chosen as a surface coating material for Zr alloys. Nevertheless, pure Cr coatings are brittle and prone to cracking and other defects. Titanium (Ti), with its good plasticity, corrosion resistance, and strength, is introduced into Cr coatings to potentially address the cracking issues of pure Cr coatings. In this study, a Ti-Cr (8: 2) coating was prepared on the surface of Zr-4 alloy using laser cladding technology to enhance the wear and corrosion resistance of the zirconium alloy surface. The prepared coating was dense, defect-free, and compositionally uniform, forming a strong metallurgical bond with the Zr-4 substrate through mutual dissolution. Compared to the Zr-4 substrate, the Ti-Cr coating exhibited a hardness of 415.4 HV, which is 2.2 times that of the substrate, and a 35.3% reduction in abrasion wear rate, demonstrating excellent wear resistance. Electrochemical tests revealed that the Ti-Cr coating had a higher self-corrosion potential and lower self-corrosion current density than the Zr-4 substrate, indicating superior corrosion resistance. This research provides important insights for developing high-performance Zr-4 alloy coatings suitable for service in demanding environments.