The invention relates to a method for preparing an antioxidant coating on the surface of tantalum alloy material, belonging to the technical field of high-temperature coating, in particular to a preparation method and properties of a high-temperature antioxidant coating used for the combustion chamber of a rail controlled engine.
Two-component liquid propellant attitude and orbit control engine is an important part of modern space vehicle and strategic and tactical weapon. It is widely used in orbit control and attitude adjustment. In recent years, the development of new aircraft or weapons has constantly raised the requirements for engine performance, requiring it to improve specific impulse and increase chamber pressure, thus reducing propellant consumption and engine weight, as well as extending engine life or increasing the range of strategic weapons. The allowable temperature of the thrust chamber is one of the main factors that determine the specific impulse of the engine, and the performance of the material and high-temperature anti-oxidation coating of the thrust chamber determines the working temperature and anti-erosion performance of the thrust chamber. At present, the tantalum alloy coated with silicide is used as the thrust chamber material for the two-component liquid rocket engines used for space vehicle orbit introduction and attitude control in China. For the tantalum and hafnium - Si/Cr/Ti engine thrust chamber, the matrix adopts tantalum and hafnium alloy, and the coating process and system are the Si/Cr/Ti coating sintered by slurry and the Si/Cr/Ti coating, whose operating temperature is about 1400°C.
The existing engine thrust chamber materials and coating systems cannot meet the higher requirements of the new generation of high specific impulse long-life rail attitude control engines for thrust chamber. According to the requirements of the new generation of orbital attitude control engine for thrust chamber, it is a solution to select tantalum alloy with stronger high temperature resistance and develop molybdenum silicide coating system with high temperature oxidation resistance on the surface of thrust chamber.
The purpose of mechanical grinding of tantalum alloy test rod is to remove the edges and burrs. The purpose of pickling is to remove oil stains, oxides and other impurities on the surface of tantalum alloy test rod. The solution used in pickling is acid, which includes nitric acid and sulfuric acid. The mass ratio of nitric acid and sulfuric acid is 4:1. The pickling time was 9 minutes, followed by ultrasonic cleaning with DEionized water, followed by drying. After drying, it was placed on the sample table of vacuum cathode arc deposition equipment. The distance between tantalum alloy sample and molybdenum target was 4mm. The thrust chamber of the trajectory control engine is used as the anode to extract vacuum and vacuum degree case for vacuum cathode arc deposition equipment.
