High-temperature oxidation-resistant NiCr/Al DUPLEX coating on CT3 STEEL SUBSTRATE

The oxidation resistance property of NiCr/Al duplex coating system has been evaluated at 800 o C during retention times of 1.5; 3; 4.5 and 6 hours. After the oxidation test, SEM-EDS data indicated the diffusion of aluminum into the NiCr coating, whereas  XRD patterns revealed the appearance of new phases (Al 3 Ni 2,  Al 2 O 3 ). In addition, an increase in micro-hardness (up to 518 - 842 Hv) was obtained after oxidation test. These obtained findings indicated that NiCr/Al coating had higher oxidation resistance than NiCr coating.