共查询到19条相似文献,搜索用时 187 毫秒
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采用置换还原法在片状铜粉上镀银。对铜粉镀银制备过程及抗氧化性能做了研究。实验结果表明,在铜粉表面首先发生置换反应,生成点缀式银颗粒,之后银颗粒长大,不完全的包覆在铜粉表面,溶液中过量的银离子在还原剂的作用下,表面银层进一步生长,得到完全包覆银的铜粉。通过X-射线衍射分析,片状铜粉镀银层表面未见氧化物,所得粉末表层结构致密。铜粉镀银层具有良好的抗高温氧化性。 相似文献
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化学还原法制备导电涂料用片状超细铜粉的研究 总被引:12,自引:1,他引:12
以CuSO4·5H2 O为原料 ,抗坏血酸为还原剂 ,NH3 ·H2 O为络合剂 ,将络合剂在反应温度加到CuSO4·5H2 O溶液中 ,再加入还原剂 ,制备了粒径分布为 1~ 10 μm的片状铜粉。探索与分析NH3 ·H2 O的用量、反应温度和CuSO4浓度对铜粉形貌及产率的影响。结果表明 :络合剂的使用是制备片状超细铜粉的关键 ,其与Cu2 + 形成络合物 ,减少溶液中游离Cu2 + 的浓度 ,控制铜的生成速度 ,并影响铜的成核和生长 ,最终形成片状铜粉。 相似文献
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用活性炭作催化剂,水作还原剂,实现钴氨脱硝法中的关键组分[Co(NH3)6]2+离子的再生,保持[Co(NH3)6]2+溶液长时高效地脱除废气中的NO。在消除扩散影响的条件下,在搅拌釜中对活性炭催化还原[Co(NH3)6]3+的反应过程进行了研究,结果表明:活性炭能催化还原[Co(NH3)6]3+的反应,而且活性炭加入量增加,反应速率也随之加快;反应速率随[Co(NH3)6]3+浓度的提高而加快;pH值是影响反应速度的一个重要因素,最佳pH值为2.74;反应温度的升高,明显地加快了反应速率。根据实验数据对该反应的本征动力学方程进行拟合,得该反应对[Co(NH3)6]3+为一级反应,反应活化能Ea=(64.62±2.06)kJ/mol。 相似文献
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《高校化学工程学报》2020,(4)
为了制备高抗氧化性能铜粉,采用AgNO_3为银源,化学镀法制备了不同含银量的超细镀银铜粉。将镀银铜粉作为导电填料制备导电胶,系统研究了制备工艺对导电胶性能的影响。结合扫描电镜(SEM)、X射线衍射(XRD)、X射线荧光(XRF)、流变仪测试、四探针电阻率测试、万能电子拉力机、热分析(DSC/TG)等分析手段,研究了镀银铜粉的形貌、晶体结构、导电胶黏度、电性能、强剪切度和固化过程热性能。结果表明:镀银铜粉具有较好的导电性及抗氧化性能。推荐最佳的导电胶制备工艺为:65%镀银铜粉、35%的环氧树脂,在150℃下固化10 min,该导电胶制备出薄膜的电阻率为8.73×10~(-4)?×cm,焊接铜片剪切强度为11 MPa,,具有优异的抗老化性能。 相似文献
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采用超声分散法,以钛酸丁酯为前驱体,硝酸银为银源,制备掺银的纳米二氧化钛粉末.并以XRD,TEM等手段对掺杂二氧化钛进行了表征,通过分析催化剂用量,以pH值对光催化速率影响为基础,研究了掺银的二氧化钛光催化剂对罗丹明B的动力学行为.结果表明,在500℃焙烧2h制备银掺杂的二氧化钛固体粉末为锐钛矿结构,催化罗丹明B反应符... 相似文献
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Deep purification of zinc ammoniacal leaching solution by cementation using zinc dust was studied.The effects of relative amount of metallic impurities,dosage of zinc dust,purification time,temperature,pH value and total ammonia concentration in the solution on the purification of the solution were investigated.The results indicate that total ammonia concentration in the solution had no effect on the purification,but relative amount of metallic impurities,dosage of zinc dust,purification time,temperature and pH value of the solution were the main factors influencing the purification.Keeping appropriate molar ratio of copper to cadmium or nickel to cadmium was beneficial to the cementation of cadmium.Nevertheless,the presence of cobalt went against the cementation of cadmium and cobalt.All metallic impurities could be decreased to acceptable levels under the optimized conditions of 2 g/L of zinc dust dosage,1 h of purification time,35℃,pH value 9.03 of zinc ammoniacal leaching solution.The deeply purified zinc ammoniacal solution obtained by one-stage purification meets the requirements of zinc electrowinning. 相似文献
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Deep Purification of Zinc Ammoniacal Leaching Solution 总被引:1,自引:0,他引:1
Deep purification of zinc ammoniacal leaching solution by cementation using zinc dust was studied. The effects of relative amount of metallic impurities, dosage of zinc dust, purification time, temperature, pH value and total ammonia concentration in the solution on the purification of the solution were investigated. The results indicate that total ammonia concentration in the solution had no effect on the purification, but relative amount of metallic impurities, dosage of zinc dust, purification time, temperature and pH value of the solution were the main factors influencing the purification. Keeping appropriate molar ratio of copper to cadmium or nickel to cadmium was beneficial to the cementation of cadmium. Nevertheless, the presence of cobalt went against the cementation of cadmium and cobalt. All metallic impurities could be decreased to acceptable levels under the optimized conditions of 2 g/L of zinc dust dosage, 1 h of purification time, 35℃, pH value 9.03 of zinc ammoniacal leaching solution. The deeply purified zinc ammoniacal solution obtained by one-stage purification meets the requirements of zinc electrowinning. 相似文献
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以蚕沙为原料,采用直接皂化法制备叶绿素铜钠盐。结果表明,最优工艺参数为:10 g干蚕沙粉在pH≈12的体系中,80℃下超声120 min;再于pH 2~3的体系中,65℃下酸化30 min,加入6 mL 10%CuSO4溶液,置铜时间90 min,最后用10%NaOH-CH3CH2OH调节溶液使叶绿素铜酸成盐析出,叶绿素铜钠盐的得率大于传统制备法,而且少一道工序,降低了成本。 相似文献