Fabrication of thermal barrier coatings on the inner surface of carbon steel tubular components via a novel mechanical alloying method

摘要

The thermal barrier coatings of NiCrAl·Y_2O_3 and NiCrAlCo·Y_2O_3 were fabricated on the inner surface of low carbon steel tubular components via a novel high-energy mechanical alloying method. The microstructure, elemental distribution and phase composition of the prepared coatings were carefully investigated by the X-ray diffraction analyzer, scanning electron microscope and energy dispersive X-ray spectroscope. The thermal oxidation experiments were performed to inspect the anti-oxidation properties of the coatings. The addition of Co element contributed to the resistance against the thermal oxidation, comparing to that of the NiCrAl·Y_2O_3 coatings and the bare substrate. The anti-oxidation mechanism of NiCrAlCo·Y_2O_3 coatings was discussed in the paper. The thermal barrier function of the coatings was greatly useful for carbon steel tubes or pipes. In addition, the thermal barrier coating fabrication method indicated more efficient and productive than many other processing methods for obtaining functional coatings. According to the analyses of the experimental results, the formation mechanisms of the deposited coatings prepared by mechanical alloying method were detailed in terms of three assumed but reasonable steps.