This paper aims to develop a special nickel-chromium-chromium carbide cermet coating deposited by subsonic velocity flame spraying with excellent quality to resist high temperature oxidation, corrosion, and erosion in boiler environment and to explore the influence of chromium carbide fraction and sealing on the coating performance. Thermal spraying has offered a cost effective, reliable solution for boiler tube protection to extend boiler life. Plasma spraying has suffered a challenge from high velocity oxygen fuel (HVOF) technique due to its high velocity, strength cohesion, and low porosity when HOVF process has become one way to obtain high quality coatings. A subsonic velocity flame spraying can satisfy the requirements, and the coatings can be done inside the boiler or the workshop. Testing results show that various coatings exhibit different characteristics of erosion wear. Paper includes a German-language abstract.