Research progress in methods for inhibiting interdiffusion between single crystal superalloys and thermal barrier coatings

Currently , the surface working temperature of second-generation or more advanced single crystal superalloy blade is above 1050 degrees C , resulting in serious interdiffusion between coating and substrate. The interdiffusion not only consumes the beneficial elements of the coating and then reduces its service life, , but also leads to the formation of secondary reaction zone in the substrate, , which will seriously damage the high-temperature mechanical performance of the single crystal superalloy. Preparing diffusion barriers and designing the low inter-diffusivity coatings are effective ways to control the interdiffusion between thermal barrier coatings and single crystal superalloy substrates. Firstly,based ,based on the latest international and domestic research progresses, , the design principles, , characteristics and classification of diffusion barriers were introduced briefly, , and then the main problems and related research studies of metal diffusion barriers, , ceramic diffusion barriers and active diffusion barriers were analyzed. Secondly, , the application and latest progress of low inter-diffusivity coatings were reviewed, , and the high-temperature protection properties and anti-diffusion mechanisms of nanocrystalline coatings, , equilibrium coatings and gamma '-based '-based coatings were discussed in detail. Finally, , the future development directions of different diffusion barriers and low inter-diffusivity coatings were pointed out