Research Status of Refractory Metal Coatings Prepared by Spraying and Laser Cladding

Refractory metals such as molybdenum, tantalum, tungsten, niobium and their alloys have the characteristics of high melting point and good high temperature performance, which play a major role in the field of protection. However, due to their high cost, high melting point, low thermal conductivity and high brittleness, their processing is relatively difficult. By using specific processes to prepare refractory metal coatings on the substrate surface to achieve excellent mechanical properties and high-temperature performance of refractory metals without changing the substrate properties, and effectively reduce manufacturing costs, which has significant research value for equipment surface protection. Because the refractory metal coatings play an increasingly important role in the manufacturing industry, the plasma spraying, explosive spraying, laser cladding and cold spraying preparation technology of molybdenum, tantalum, tungsten, niobium and other refractory metal coatings were introduced firstly, and the characteristics of each process were summarized. On this basis, the microstructure and properties of refractory metal coatings prepared by different processes were analyzed and compared, and the improvement progress was summarized from three aspects of coating material composition and structure, process parameters and post-treatment. Finally, the existing problems and development directions of the refractory metal coating preparation technology were prospected.