Preparation and Deuterium Permeation Properties of Ti/AlN/Ti/AlN Multiple Coatings

To improve the stability and tritium permeation resistance of the AlN single-layer coating, a Ti-AlN system coating was proposed. Ti/AlN/Ti/AlN multiple coatings with dense structure and total thickness of about 500 nm were prepared on the substrate surfaces of 316L stainless steel by magnetron sputtering. The coated samples were heat-treated under different conditions, and the microstructure and phase composition before and after heat treatment were analyzed by SEM, XRD and AES. The deuterium permeation experiments at 200 similar to 600 degrees C were then conducted for all the samples. The results show that only some amount of Al3Ti products are formed at the Ti-AlN interface for all the coated samples heated at 760 degrees C for 4 h. Among all the coated samples, the coated sample with heat-treated temperature of 700 degrees C and heating rate of 1.5 degrees C/min exhibits the best deuterium permeation resistance, and its PRF (permeation reduction factor) value at 600 degrees C is 536. When the heat-treated temperature is increased to 760 degrees C or the heating rate is increased to 2.5 degrees C/min, the cracking of the coating will be obviously aggravated, which lowers the deuterium permeation resistance. On the other hand, with the decrease of the penetration temperature, the PRF values of all the coated samples also decrease sharply, indicating that the temperature change during the deuterium penetration process would cause the failure of the deuterium barrier properties of the multiple coating.