The deposition kinetics and microstructure of chemical vapor deposition (CVD) of Nb on the Mo substrate at different deposition variables is investigated. The morphology of CVD Nb is columnar, it exhibits a strong preferred orientation and its growth direction is perpendicular to the substrate surface, the deposition rate and grain size increased with the increase of deposition temperature. The deposition rate conforms to the Arrhenius formula, the activation energy [Formula: see text] at high temperature and low temperature is 0.85 kJ/mol and 7.2 kJ/mol, respectively. The rate-limiting step for CVD Nb at high temperature is chemical reaction step, whereas that is the mass transport step at low temperature. Chlorination temperature has a weak influence on deposition rate and grain structure, the deposition rate and grain size of CVD Nb increased with the increase of the chlorine flow and hydrogen flow, the maximum deposition rate is [Formula: see text], thus, the optimum deposition temperature is 1200[Formula: see text]C, chlorination temperature is 350[Formula: see text]C, hydrogen flow is 400 ml, chlorine flow is 200 ml.

Nickel-based super alloy, niobium alloy, refractory metal and carbon fiber reinforced composite are the most common structural materials used in aviation and spaceflight fields. Reduced oxidation and corrosion resistance at high temperature are limiting factors to the application of theses materials. Adapted protective coatings such as pure precious metal coatings, precious metal alloy and precious metal composite coatings can be applied on the surface of theses materials. New advances of oxidation protective coating in recent years are reviewed in this paper, combined with some research on the preparation of iridium

Carbon fiber reinforced silicon carbide composite (Cf/SiC) is the new high temperature ceramic composite developed in recent years, widely used in the aviation, aerospace and other high-tech fields. In this paper, a variety of joining methods of Cf/SiC composite to metallic materials, including active filler brazing, solid phase diffusion welding, liquid infiltration joining, as well as chemical vapor deposition of niobium transition joining technology were introduced. At the same time, the features and disadvantages of each technique were evaluated. This review is intended to provide a comprehensive guide to the design and application of Cf/SiC composite joining to metals.