Abstract:Glass-ceramic coating of different molar ratios deposited on the metal support (NiCrFe alloy) was prepared by a sol-gel method, with tetra-ethyl orthosilicate (TEOS) and aluminium nitrate (Al(NO3)3·9H2O) as the starting materials. The effects of different preparation parameters on the morphology, crystal quality and the bonding strength of the coating were studied. Characterization of XRD and SEM and the tests of thermal shock, ultrasonic vibration and tension show that the coating can increase the specific surface area and enhance the bonding strength between the metal support (NiCrFe alloy) of diesel engine catalytic converters and the coating. Moreover, the calcination temperature of the coating is lower and the preparation is much simpler than the traditional ones. Optimal parameters are found to be as follows: pre-oxidation of the metallic supports should be performed at 900 oC, the molar ratio of silicon to aluminum is 5:1, the coating drying is performed at 70 oC for 2 h and calcining is at 650 oC for 2 h.