Papers by Author: Cai Min Huang

Abstract: A new ternary compound TbCo0.67Ga1.33 was discovered and studied by means of X-ray powder diffraction technique. The crystal structure of the new compound was refined by using Rietveld method from X-ray powder diffraction data. This compound crystallizes in the orthorhombic with the CeCu2 structure type( space group Imma, a = 0.43384(6) nm, b = 0.70193(1) nm, c = 0.75617(1) nm, Z = 4, and Dcalc = 8.512 g/cm3 ). The Rietveld refinement results were Rp = 0.0996, Rwp = 0.1277.

Abstract: Al-8%Si alloy double-coating on Q235 steel were produced, Then the samples were executed diffusion at high temperatures protecting with flowing argon gas. Scanning electron microscope (SEM), optical microscope (OM), and energy dispersive X-ray spectroscope (EDS) were employed for microstructure observation of cross-sectional, surface and compositional analysis of coating. The diffusion mathematical model was established with the finite element method. The results show that good quality Al-8%Si coating is made; after heat-diffusion treatment, the new phases FeAl and Fe3Al presents; Silicon atoms in Al-8%Si alloy can hinder the diffusion of aluminum atoms into steel substrate at high temperature; Al-8%Si alloy double-coating sample’s high-temperature oxidation resistance is higher than Q235 steel. This material is hopefully used in the engine exhaust manifold.

Abstract: Hot-dip aluminizing panels of Q235 steels were produced in laboratory. Then the hot-dip aluminizing samples were executed diffusion at elevated temperatures protecting with flowing argon gas. Metallographic microscope, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were employed for compositional analyses and graphical analyses of coating. The diffusion process was researched and the phase’s microstructure after diffusion was analyzed and discussed. The hot-dip aluminizing diffusion mathematical model was established with the finite element method. The results show that after diffusion in hot-dip aluminizing, the aluminum of the coating disappeared. The thickness of diffusion layer increased and the dentate frame disappeared. There are some iron-rich phases such as Fe2Al5, FeAl and Fe3Al in the diffusion layer. The phase Fe2Al5 decreases and the phase FeAl increases. The mathematical model corresponds with the actual situation. The diffusion coefficients of Al atoms diffusing in intermetallic compounds were calculated at 950°C, which were 0.29×10-12 m2/s for Fe2Al5, 0.7×10-12 m2/s for FeAl, and 0.27×10-12 m2/s for Fe3Al, respectively.