Parametric Study to Repair Leaks in Water Pipe Using the Low-Pressure Cold Spray Technique

Water leakage due to corrosion damage is a significant issue in thermal and nuclear power plants. This study proposes to use a low-pressure cold spray (LPCS) method to repair efficiently active leaks in pipes. A mixture of Sn/Zn powder was cold sprayed over a 0.5 mm diameter active leaking hole using the LPCS method at various parameters, viz., powder mixing ratio, gas temperature, and gas pressure. The results demonstrated that the hole could be plugged within 10 s by the rigid layer of coating formed by the LPCS method, even though the active water continued to flow through the pipe. Based on the results, the effect of the powder mixing ratio, gas temperature, and gas pressure on the coating hardness, components, and thickness have been studied in detail. Furthermore, the particle velocity/temperature was calculated by computational fluid dynamics simulations to clarify the particle impact behavior. Moreover, the microstructure of the coating-substrate interface was observed using scanning electron microscopy, and the bonding mechanism of the mixed powder has been discussed.