A A cerium-based chemical conversion process was studied. First, zinc coating obtained from a free-cyanide alkaline bath, with derivative of imidazol with new brightener, was investigated, zinc-plated steel specimens...A A cerium-based chemical conversion process was studied. First, zinc coating obtained from a free-cyanide alkaline bath, with derivative of imidazol with new brightener, was investigated, zinc-plated steel specimens were treated with a solution of 50 mmol· L^-1 Ce(NO3 )3 The corrosion behavior of bare and treated mild galvanized steel was evaluated during exposure to 0.5 mol · L^-1 NaCl for different immersion time, using Tafel polarization curves and electrochemical impedance spectroscopy (EIS) measurements. The surface morphology of the coating was studied using scanning electron microscopy (SEM). The composition and chemical percent of the coating were examined by X-ray dispersion energy (EDAX). The results of these measurements showed that the newly developed cerium-based conversion coating process was a promising candidate for replacing the conventional chromate treatments used at present for galvanized steel.展开更多
开发了酸性无氰镀镉新工艺NCC-617。镀液组成为:氯化镉35-40 g/L,配位剂120-160 g/L,氯化钾140-180 g/L,光亮剂1.5-2.5 m L/L,辅助剂25-35 m L/L,p H 6.0-7.0。工艺条件为:挂镀──温度15-35℃,阴极电流密度0.5-1.5 A/dm^2;滚镀温度15...开发了酸性无氰镀镉新工艺NCC-617。镀液组成为:氯化镉35-40 g/L,配位剂120-160 g/L,氯化钾140-180 g/L,光亮剂1.5-2.5 m L/L,辅助剂25-35 m L/L,p H 6.0-7.0。工艺条件为:挂镀──温度15-35℃,阴极电流密度0.5-1.5 A/dm^2;滚镀温度15-30℃,槽电压4-7 V,滚筒转速3-5 r/min。在电流密度1 A/dm2下,镉的沉积速率为0.33μm/min。NCC-617镀液的电流效率为73%,均镀能力为41%-52%,深镀能力为9.2。镀镉层经低铬彩色钝化后中性盐雾试验2 000 h仍无白锈生成,其耐蚀性实现了重大突破。镀层的氢脆性和结合力合格。总之,NCC-617镀镉工艺具有镀液稳定,镀层性能优良,电镀废水容易处理的优点,具有较好的应用前景。展开更多
以自制焦磷酸盐为主要原料,加入适当的添加剂,对经表面处理的玻璃钢制品进行无氰Cu Zn Sn Co四元合金仿金电镀,讨论了镀液组分及工艺参数对镀层质量的影响。试验结果表明,在温度为30~50℃,电流密度为0.3~0.7A/dm2,pH值为7.0~9.0的条...以自制焦磷酸盐为主要原料,加入适当的添加剂,对经表面处理的玻璃钢制品进行无氰Cu Zn Sn Co四元合金仿金电镀,讨论了镀液组分及工艺参数对镀层质量的影响。试验结果表明,在温度为30~50℃,电流密度为0.3~0.7A/dm2,pH值为7.0~9.0的条件下,可获得18~24K金色镀层,经有效的后处理工艺,可使镀层色泽均一,性能稳定。展开更多
基金Project supported by the Office of the New Material and Clean Chemistry Research of the Tabriz University
文摘A A cerium-based chemical conversion process was studied. First, zinc coating obtained from a free-cyanide alkaline bath, with derivative of imidazol with new brightener, was investigated, zinc-plated steel specimens were treated with a solution of 50 mmol· L^-1 Ce(NO3 )3 The corrosion behavior of bare and treated mild galvanized steel was evaluated during exposure to 0.5 mol · L^-1 NaCl for different immersion time, using Tafel polarization curves and electrochemical impedance spectroscopy (EIS) measurements. The surface morphology of the coating was studied using scanning electron microscopy (SEM). The composition and chemical percent of the coating were examined by X-ray dispersion energy (EDAX). The results of these measurements showed that the newly developed cerium-based conversion coating process was a promising candidate for replacing the conventional chromate treatments used at present for galvanized steel.
文摘以自制焦磷酸盐为主要原料,加入适当的添加剂,对经表面处理的玻璃钢制品进行无氰Cu Zn Sn Co四元合金仿金电镀,讨论了镀液组分及工艺参数对镀层质量的影响。试验结果表明,在温度为30~50℃,电流密度为0.3~0.7A/dm2,pH值为7.0~9.0的条件下,可获得18~24K金色镀层,经有效的后处理工艺,可使镀层色泽均一,性能稳定。