Fabrication and characterization of Al_2O_3-metal composite coating on steel plate with nonpressure combustion synthesis

摘要

Al2O3-metal composite coatings with different reactants and diluents were fabricated on mild steel plate with nonpressure combustion synthesis process. The coatings were characterized by means of X-ray diffraction, scanning electron microscopy, and energy-dispersive spectrometry, respectively. Thermal shock tests were carried out to determine the bond strength of the coating with the steel substrate. The results indicate that the coating is composed of a-Al2O3, a-(Fe–Cr) and Al2SiO5 as the main phases. It is found that the coating with the diluents of Al2O3–SiO2 and transition layer of Al2O3–Cr presents the highest hardness of 2270 HV0.2 and the lowest porosity of 3.93 %. Owing to a metallurgical bond of the coating-to-substrate, the coating exhibits a good thermal shock resistance.