以Ag2O为前驱体,葡萄糖为还原剂,聚乙烯吡咯烷酮(PVP)等为分散剂,对沉淀转化法制备超细银粉进行了研究。试验考察了反应体系pH值、分散剂、葡萄糖浓度及反应温度对银粉形貌与粒度的影响。结果表明,随着pH值的增加,银粉粒径呈先减小后增...以Ag2O为前驱体,葡萄糖为还原剂,聚乙烯吡咯烷酮(PVP)等为分散剂,对沉淀转化法制备超细银粉进行了研究。试验考察了反应体系pH值、分散剂、葡萄糖浓度及反应温度对银粉形貌与粒度的影响。结果表明,随着pH值的增加,银粉粒径呈先减小后增大的趋势,偏酸性体系中银粉粒径分布较宽,而偏碱性体系中颗粒团聚明显且其粒径分布宽;以PVP为分散剂可制备出分散性良好的类球形超细银粉;提高葡萄糖浓度,银粉粒径减小;温度升高银粉粒径增大且团聚严重。在100mL高纯水中加入8 g Ag2O和0.08 g PVP,控制反应温度为30℃,接着并流加入0.35 mol/L葡萄糖溶液和0.18 mol/L氨水溶液,控制体系pH值为8的条件下,可制备出粒径在1μm左右且分散良好的类球形超细银粉,其粒度可调。展开更多
This article adopts the double decomposition method, select the appropriate experimental conditions and operation process, respectively add appropriate amount of sodium carboxymethyl cellulose （CMC） as crystal contr...This article adopts the double decomposition method, select the appropriate experimental conditions and operation process, respectively add appropriate amount of sodium carboxymethyl cellulose （CMC） as crystal control agent to study the influence of crystalline of ultrafine calcium carbonate. The experimental results show that the different concentrations of CMC as crystal control agent on the morphology and crystal structure of calcium carbonate have obvious effect, which emerge morphology change from square to spherical, crystalline transition from calcite to aragonite. Thus, the results provide experimental data and theoretical basis for the use of different additives, and provide experimental basis and feasible solution for this kind of reaction.展开更多
The spherical silver mirco/nano-particles with narrow size distributions were obtained by chemical reduction of silver ammonia solution with ascorbic acid as reducing agent and bovine serum albumin (BSA) as bio-templa...The spherical silver mirco/nano-particles with narrow size distributions were obtained by chemical reduction of silver ammonia solution with ascorbic acid as reducing agent and bovine serum albumin (BSA) as bio-template. The effects of the concentration of Ag+ ions, BSA and ammonia, reactive temperature on the silver morphology and particle sizes were investigated. SEM, TEM and XRD were employed to characterize the morphology and structures of the prepared silver mirco/nano-particles. The results show that the spherical silver particle with smooth surface and narrow size distributions can be obtained by controlling the concentration of Ag+ ions, BSA, reaction temperature, etc. By controlling the above parameters, the silver spherical mirco/nano-particles with particle sizes ranging from 0.2 to 2.3 m can be well prepared, which is expected to be used in manufacturing high performance electronic pastes.展开更多
文摘以Ag2O为前驱体,葡萄糖为还原剂,聚乙烯吡咯烷酮(PVP)等为分散剂,对沉淀转化法制备超细银粉进行了研究。试验考察了反应体系pH值、分散剂、葡萄糖浓度及反应温度对银粉形貌与粒度的影响。结果表明,随着pH值的增加,银粉粒径呈先减小后增大的趋势,偏酸性体系中银粉粒径分布较宽,而偏碱性体系中颗粒团聚明显且其粒径分布宽;以PVP为分散剂可制备出分散性良好的类球形超细银粉;提高葡萄糖浓度,银粉粒径减小;温度升高银粉粒径增大且团聚严重。在100mL高纯水中加入8 g Ag2O和0.08 g PVP,控制反应温度为30℃,接着并流加入0.35 mol/L葡萄糖溶液和0.18 mol/L氨水溶液,控制体系pH值为8的条件下,可制备出粒径在1μm左右且分散良好的类球形超细银粉,其粒度可调。
文摘This article adopts the double decomposition method, select the appropriate experimental conditions and operation process, respectively add appropriate amount of sodium carboxymethyl cellulose （CMC） as crystal control agent to study the influence of crystalline of ultrafine calcium carbonate. The experimental results show that the different concentrations of CMC as crystal control agent on the morphology and crystal structure of calcium carbonate have obvious effect, which emerge morphology change from square to spherical, crystalline transition from calcite to aragonite. Thus, the results provide experimental data and theoretical basis for the use of different additives, and provide experimental basis and feasible solution for this kind of reaction.
基金supported by the National Natural Science Foundation of China (Grant No. 51271135) "New Century Talents Project" of Ministry of Education and Fundamental Research funding of Xi'an Jiaotong Universitythe project of Innovative Team of Shaanxi Province (Grant No. 2013KCT-05)
文摘The spherical silver mirco/nano-particles with narrow size distributions were obtained by chemical reduction of silver ammonia solution with ascorbic acid as reducing agent and bovine serum albumin (BSA) as bio-template. The effects of the concentration of Ag+ ions, BSA and ammonia, reactive temperature on the silver morphology and particle sizes were investigated. SEM, TEM and XRD were employed to characterize the morphology and structures of the prepared silver mirco/nano-particles. The results show that the spherical silver particle with smooth surface and narrow size distributions can be obtained by controlling the concentration of Ag+ ions, BSA, reaction temperature, etc. By controlling the above parameters, the silver spherical mirco/nano-particles with particle sizes ranging from 0.2 to 2.3 m can be well prepared, which is expected to be used in manufacturing high performance electronic pastes.
