Silane coupling agent KH560 was used to modify the surface of nano-α-Al<sub>2</sub>O<sub>3</sub> in ethanol-aqueous solution with different proportions. The particle size of nano-α-Al<sub&...Silane coupling agent KH560 was used to modify the surface of nano-α-Al<sub>2</sub>O<sub>3</sub> in ethanol-aqueous solution with different proportions. The particle size of nano-α-Al<sub>2</sub>O<sub>3</sub> was determined by nano-particle size analyzer, and the effects of nano-α-Al<sub>2</sub>O<sub>3</sub> content, ethanol-aqueous solution ratio and KH560 dosage on the dispersion and particle size of nano-α-Al<sub>2</sub>O<sub>3</sub> were investigated. The material structure before and after modification was determined by Fourier transform infrared spectroscopy (FTIR). Aqueous polyurethane resin and inorganic components are combined with modified nano-α-Al<sub>2</sub>O<sub>3</sub> dispersion to form chromium-free passivation solution. The solution is coated on the galvanized sheet, the adhesion and surface hardness are tested, the bonding strength of the coating and the surface hardness of the substrate are discussed. The corrosion resistance and surface morphology of the matrix were investigated by electrochemical test, neutral salt spray test and scanning electron microscope test. The chromium-free passivation film formed after the modification of nano-α-Al<sub>2</sub>O<sub>3</sub> increases the surface hardness of galvanized sheet by about 85%. The corrosion resistance of the film is better than that of a single polyurethane film. The results show that the surface hardness and corrosion resistance of polyurethane resin composite passivation film are significantly improved by the introduction of nano-α-Al<sub>2</sub>O<sub>3</sub>.展开更多
以板状刚玉颗粒与细粉、α-Al2O3微粉、金属Al粉、MgO细粉和石墨为原料,酚醛树脂为结合剂,在加入4%( w )Al粉基础上,用< 0.088 mm 的MgO细粉等量替代刚玉粉,研究MgO细粉加入量(质量分数分别为0、1%、3%和5%)对Al复合Al2O3-C不烧滑板...以板状刚玉颗粒与细粉、α-Al2O3微粉、金属Al粉、MgO细粉和石墨为原料,酚醛树脂为结合剂,在加入4%( w )Al粉基础上,用< 0.088 mm 的MgO细粉等量替代刚玉粉,研究MgO细粉加入量(质量分数分别为0、1%、3%和5%)对Al复合Al2O3-C不烧滑板材料性能、组成和显微结构的影响。结果表明:不加MgO细粉时,金属Al与C和N2反应生成纤维状Al4C3和AlN而起增强增韧作用,材料具有较高的高温强度和优良的抗热震性。MgO细粉加入量为1%( w )时,材料保持较高的高温强度和优良的抗热震性,材料中有较多纤维状Al4C3和AlN生成。MgO细粉加入量≥3%( w )时,材料的高温强度和抗热震性明显下降,这是由于MgO与基体中Al2O3以及Al反应生成的Al2O3发生反应生成MgAl2O4膨胀,进而产生较多裂纹,同时Al4C3和AlN生成量明显降低。但随着MgO细粉加入量的增加,材料的抗氧化性提高,这是由于在试样外层形成MgAl2O4致密层,阻碍氧气向材料内部扩散。展开更多
文摘Silane coupling agent KH560 was used to modify the surface of nano-α-Al<sub>2</sub>O<sub>3</sub> in ethanol-aqueous solution with different proportions. The particle size of nano-α-Al<sub>2</sub>O<sub>3</sub> was determined by nano-particle size analyzer, and the effects of nano-α-Al<sub>2</sub>O<sub>3</sub> content, ethanol-aqueous solution ratio and KH560 dosage on the dispersion and particle size of nano-α-Al<sub>2</sub>O<sub>3</sub> were investigated. The material structure before and after modification was determined by Fourier transform infrared spectroscopy (FTIR). Aqueous polyurethane resin and inorganic components are combined with modified nano-α-Al<sub>2</sub>O<sub>3</sub> dispersion to form chromium-free passivation solution. The solution is coated on the galvanized sheet, the adhesion and surface hardness are tested, the bonding strength of the coating and the surface hardness of the substrate are discussed. The corrosion resistance and surface morphology of the matrix were investigated by electrochemical test, neutral salt spray test and scanning electron microscope test. The chromium-free passivation film formed after the modification of nano-α-Al<sub>2</sub>O<sub>3</sub> increases the surface hardness of galvanized sheet by about 85%. The corrosion resistance of the film is better than that of a single polyurethane film. The results show that the surface hardness and corrosion resistance of polyurethane resin composite passivation film are significantly improved by the introduction of nano-α-Al<sub>2</sub>O<sub>3</sub>.
文摘以板状刚玉颗粒与细粉、α-Al2O3微粉、金属Al粉、MgO细粉和石墨为原料,酚醛树脂为结合剂,在加入4%( w )Al粉基础上,用< 0.088 mm 的MgO细粉等量替代刚玉粉,研究MgO细粉加入量(质量分数分别为0、1%、3%和5%)对Al复合Al2O3-C不烧滑板材料性能、组成和显微结构的影响。结果表明:不加MgO细粉时,金属Al与C和N2反应生成纤维状Al4C3和AlN而起增强增韧作用,材料具有较高的高温强度和优良的抗热震性。MgO细粉加入量为1%( w )时,材料保持较高的高温强度和优良的抗热震性,材料中有较多纤维状Al4C3和AlN生成。MgO细粉加入量≥3%( w )时,材料的高温强度和抗热震性明显下降,这是由于MgO与基体中Al2O3以及Al反应生成的Al2O3发生反应生成MgAl2O4膨胀,进而产生较多裂纹,同时Al4C3和AlN生成量明显降低。但随着MgO细粉加入量的增加,材料的抗氧化性提高,这是由于在试样外层形成MgAl2O4致密层,阻碍氧气向材料内部扩散。
