共查询到19条相似文献,搜索用时 203 毫秒
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硫酸盐体系三价铬镀铬工艺及镀层性能的研究 总被引:1,自引:0,他引:1
采用硫酸盐体系进行三价铬镀铬,获得了光亮银白色镀层。分别研究了镀液的pH值、镀液温度、电流密度、热处理温度等对镀层硬度的影响;分别用X射线衍射法、扫描电镜法等研究了镀层的性质。当溶液的pH值为2.4,镀液温度为45℃,电流密度为45 A/dm2时,镀层的硬度和摩擦系数分别为7 740 MPa和0.816。镀层分别在25℃,200℃,250℃,300℃和350℃下进行热处理,镀层的硬度分别为7 740 MPa,8 750 MPa,9 010 MPa,9 250 MPa,9 450 MPa,镀层的硬度增加的原因可能是镀层由非晶态向晶态转化所致。 相似文献
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缸筒镀铬工艺中阳极的改进 总被引:1,自引:1,他引:0
镀硬铬溶液分散能力差,阴极(缸筒)电流密度分布不均匀,缸筒上下镀层厚度差较大,超厚镀层需要研磨除去,为了改变老式阳极镀铬中出现较大的厚度差,对镀铬老式阳极进行了改造,它改善了缸筒电流密度的分布,使镀层厚度趋于一致(能使镀层厚度差接近于零或等于零),取得了较好的效果. 相似文献
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指出了锌合金压铸件电镀的特殊性.介绍了适用于锌合金压铸件的镀装饰铬工艺,其流程主要包括:超声波有机溶剂去油,浓硫酸除蜡油,稀酸活化,表面调整,氰化镀铜,焦磷酸盐镀铜,酸性光亮镀铜,光亮镀镍,镀铬,烘干,检验.给出了各工序的工艺条件、控制要点及常见故障的处理. 相似文献
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从电镀污泥中回收铜、镍、铬的工艺研究 总被引:1,自引:0,他引:1
介绍了一套完整的电镀污泥回收处理工艺.该工艺采用焙烧法将污泥中的金属组分同类分离,并结合黄钠铁矾沉淀法去除杂质铁等工艺对铜、镍、铬进行了回收利用.该工艺具有处理量大,回收率高,产品质量好,无二次污染等优点. 相似文献
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锌铁合金电镀工艺研究 总被引:2,自引:0,他引:2
研究了碱性锌酸盐锌铁合金电镀工艺,探讨了各工艺条件对镀层铁含量的影响.通过控制工艺条件,获得了含铁量为9%~12%的光亮锌铁合金镀层.最佳工艺条件为:znO 8~10 g/L,NaOH 110~130 g/L,三乙醇胺20~30 mL/L,FeSO4·7H2O3.3~4.5 g/L,添加剂30~60mL/L,阴极电流密度1~2A/dm2,搅拌速率160~240r/min,温度28~35℃.电化学极化测试和中性盐雾腐蚀试验的结果表明,采用此工艺所得锌铁合金镀层的耐蚀性明显优于纯锌镀层. 相似文献
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采用酸浸-铁氧体化-毒性浸出分析工艺实现电镀污泥的资源化.对电镀污泥中重金属的硫酸浸出工艺进行了研究,考查了液固比、时间、温度的影响.结果表明:在液固质量比为5∶1,时间为60 min,温度为25℃时,污泥中重金属的浸出率最佳.向重金属浸出液中加入硫酸亚铁,通入空气,控制pH值和温度条件下制备铁氧体材料,结果表明:在pH为9,铁和其他重金属M的摩尔比为8∶1,温度为80℃,时间为120 min的条件下,所得铁氧体结构稳定,滤液中重金属的浓度最低,远低于国家规定的一级排放标准值,可安全排放.对硫酸浸出残渣和铁氧体进行毒性浸出分析,结果均低于TCLP毒性鉴别标准值,已达到无害化,残渣可安全填埋,铁氧体可作为工业产品应用. 相似文献
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分别讨论了工件内腔镀硬铬液的组分———铬酸酐、硫酸和三价铬的含量对镀层性能的影响:铬酸酐的含量过高,镀层硬度降低。硫酸根的含量过高,镀液的分散能力和电流效率降低,并且镀液中Cr3 的含量上升;含量过低,会使镀件凹处的镀层薄,甚至无镀层沉积。Cr3 含量偏高,槽电压升高,光亮区变窄;含量偏低,分散能力降低,镀层光泽性不好,镀后工件水洗性不好。其最佳含量分别为:铬酸酐220~250g/L,硫酸与铬酸酐的质量比1∶(110~120),Cr3 2~4g/L。分别对30℃、40℃和50℃下的铬酐的质量浓度与镀液密度的关系,电镀过程中镀液温度与阴极电流密度及其与工件形状、阳极的设计和电极间距的关系,以及工件的预热温度、冲击电流和反向蚀刻等操作规范进行了介绍。 相似文献
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A microprocessor-controlled flow plating process was developed to deposit laminated chromium consisting of alternating layers of low contraction (LC) and high contraction (HC) chromium. The automated plating system contains a large number of variable parameters designed to allow the use of multiple plating modes. The available modes include a combination of direct current, interrupted, periodic reverse, pulse and laminated chromium plating.The laminated plating experiments were conducted at LC/HC solution temperatures of 85 and 55°C, current densities of 120 and 45 A dm–2, and at LC/HC duty cycles to produce spacings between 0.01 and 2.7 m. Under these plating conditions, deposits with hardness values between 655 and 1089 KHN (Knoop hardness number, kg mm–2) and tensile strengths between 6.8 and 57.2 were obtained.This paper was presented at a workshop on the electrodeposition of refractory metals, held at Imperial College, London, in July 1985. 相似文献
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A seawater desalination plant using a nuclear heating reactor (NHR) coupled with the multi-effect distillation (MED) process was developed by the Institute of Nuclear Energy Technology, Tsinghua University, China. The seawater desalination plant was designed to supply potable water demand to some coastal location or island where both fresh water and energy sources are severely lacking. The NHR design possesses intrinsic and passive safety features, which was demonstrated by the NHR-5 experiences. The intermediate circuit and steam circuit were designed as the safety barriers between the NHR and MED desalination systems. With the power range of the heating reactor within 10 to 200 MWt, the desalination plant could provide 8,000 to 160,000 m3/d of potable water of appropriate quality. The design concept and parameters, safety features, and comparative investigation of coupling schemes are presented in the paper. 相似文献