The oxidation behaviors of Cr, Cr93.4Al6.6, Cr58.1Al41.9, and Cr34.5Al65.5 coatings, deposited by using multi-arc ion plating technology, at high temperature were studied. The weight gain, oxide thickness, morphology, and phase composition of the coatings before and after oxidation were analyzed in detail. The results show that there is an Al content window available for tuning the oxidation behaviors of the CrAl-based coatings. The Cr93.4Al6.6 coating is considered to be most protective and can effectively improve the high-temperature oxidation resistance of the substrate; whereas, too high an Al content has a harmful effect on the antioxidant properties of the coatings. The oxidation mechanism of Cr and CrAl coatings were also discussed.

Friction and wear performance is one of the key mechanical properties of accident tolerant fuel cladding coatings. In this study, reciprocating sliding wear tests had performed on two types of CrAl and CrAlN coatings with two different Al content ratios and Zr-4. The coefficient of friction, wear depth, and abrasion loss were measured and compared. The results indicated that the CrAl-based coatings improve the wear behavior significantly and nitrogen has an obvious improvement on the wear resistance of the coating. The friction and wear performance was also studied in a water environment. The results show that the presence of water degrade the wear performance of Zr-4 and CrAl coatings but ameliorates the friction and wear performance of CrAlN coatings. The feasibility of depositing ATF coating on conventional Zr-4 substrates to mitigate the influence of grid-to-rod fretting was demonstrated.

Friction and wear resistance are important factors that affect the selection of accident-tolerant fuel coating materials. In this study, the wear behavior of a series of Cr-N_x coatings with different N contents was investigated using a reciprocating sliding tester. The coating morphology, change in the coefficient of friction during the friction and wear tests, and wear volume after the friction and wear tests, were characterized and discussed in detail. The results show that the Cr₂N coating has better anti-friction and wear resistance behaviors than the Cr and CrN coatings under anhydrous and aqueous conditions. In addition, the water environment promoted the wear of the Zr-4 alloy and Cr coatings and inhibited the wear of the CrN and Cr₂N coatings. The mechanisms of friction and wear were also discussed.