Tantalum and tantalum alloys' high temperature oxidation resistant coatings

Advantages of tantalum

Tantalum and tantalum alloy have the advantages of high melting point, good corrosion resistance, excellent high temperature strength, good machining performance, weldability, low plastic/brittle transition and excellent dynamic mechanical properties. It is widely used in electronics, weapons, chemical industry, aerospace industry and space nuclear power system, etc. It is an ideal structural material for working at 1600 ℃~1 800 ℃.  Although tantalum and tantalum alloy have excellent mechanical properties at high temperature, their oxidation resistance is poor at high temperature. Molybdenum metal will be oxidized to Ta205 when it is above 500℃. Due to the above characteristics, the application of tantalum and tantalum alloy is seriously restricted. It is of great significance to expand its application scope and improve the high temperature and oxidation resistance of tantalum and tantalum alloy. There are two main methods of high temperature oxidation resistance protection of tantalum and tantalum alloy: 1. high temperature oxidation resistance protection of surface coating. 2. high temperature oxidation resistance protection of alloy. 

Although alloying method can improve the oxidation resistance of tantalum and tantalum alloy, the premise is that alloying element dosage must reach above the critical value to protect the matrix, and at the same time, it will have a great influence on other properties of the matrix, especially on the mechanical properties of the matrix at high temperature.  

Surface coating can have lower oxygen permeation ability at the same time, good chemical and physical compatibility and stability, low volatility, good thermal expansion coefficient matching and combining ability, high temperature self healing ability and cannot affect tantalum alloy base material original advantages such as good mechanical properties is solve tantalum alloy high temperature mechanical properties and oxidation resistance of the best method.

Tantalum and tantalum alloy materials, as the key components of high-temperature structural materials, have an increasingly bright application prospect in aviation, aerospace, nuclear and weapon fields. Therefore, tantalum and tantalum alloy oxidation resistant coating technology is also toward high temperature resistance, long life, erosion resistance and other directions.

1.  Adding alloying elements to improve tantalum and tantalum alloy properties. The balance between oxidation properties and mechanical properties can meet the needs of the service environment.  

2. Develop the preparation technology of composite coating. A variety of surface coating technologies are used to realize the composite structure of the coating and improve the control ability of the process parameters in the process of coating preparation.  

3. Development of new coating Technology The physicochemical bonding between inner and outer layers of composite coating and substrate will be one of the focuses of future research work.  

4. Reducing the cost, simplifying the production process and shortening the synthesis cycle will also be one of the development directions of antioxidant coating in the future.