共查询到18条相似文献,搜索用时 156 毫秒
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三价铬超声-脉冲电沉积Cr/SiC纳米复合镀层 总被引:1,自引:0,他引:1
利用超声-脉冲电沉积法,在三价铬镀液中,添加羧酸盐-尿素配合剂和SiC纳米颗粒,制备了Cr/SiC复合镀层。研究了超声-脉冲工艺参数对纳米SiC复合量、镀层厚度的影响。利用电化学法分析了超声波对三价铬电沉积Cr/SiC复合镀层的电化学行为。结果表明,超声-脉冲作用均有利于基质金属铬的电沉积,从而提高镀层厚度及SiC复合量。利用SEM、XRD、和EDS分别对Cr/SiC复合镀层的表面形貌、微观结构和组成等进行表征。结果表明,采用该技术可制备厚度为13.5μm、SiC含量为5.5%的Cr/SiC纳米复合镀层。 相似文献
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六价铬电沉积工艺毒性高、污染大,三价铬电沉积工艺低毒、低污染,应用前景广阔.运用正交设计法优化了镀铬液配方,确定了其工艺参数,研究了影响脉冲电沉积纳米铬镀层质量的主要工艺因素,分析了镀液组成对铬镀层厚度和电流效率的影响,得到了羧酸盐-尿素体系脉冲电沉积纳米晶铬镀层的最佳工艺.结果表明:影响镀层厚度的主次因素分别是配位剂A(柠檬酸钠)、配位剂B(碳原子数不少于8的一元羧酸盐)和CrCl3˙6H2O的浓度;影响电流效率的主次因素分别是配位剂A、CO(NH2)2和配位剂B的浓度.扫描电镜观察和电子能谱分析结果表明,铬镀层晶粒尺寸小于100nm,厚度均匀,表面光滑,结晶细致.该工艺能制备厚度为11.2um的铬镀层,其电流效率高达25.32%. 相似文献
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为了开发替代六价铬电镀的三价铬电镀工艺,采用氯化物三价铬镀液体系,在30CrMnSi高强度钢上制备了厚度100μm以上的厚铬镀层,其沉积速率为1.2 μm/min;通过扫描电子显微镜、X射线光电子能谱、中性盐雾试验、动电位极化曲线和电化学阻抗对镀层的微观形貌、化学组成和耐蚀性进行了表征和分析。结果表明:三价铬镀铬层由金属铬、氢氧化铬和氧化铬组成;镀层表面为瘤状小球结构,结晶致密、有小孔及微裂纹;镀层与基体结合力良好;铬镀层表现出典型的钝化行为,抗盐雾处理后的铬镀层经过232h中性盐雾试验无锈蚀。 相似文献
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In this communication, we present a generalization of our investigations concerning current state in the development of trivalent chromium baths as an environmentally friendly alternative to hazardous electroplating baths containing extremely toxic hexavalent chromium compounds. The main technological properties of sulfate trivalent chromium baths containing carbamide and formic acid as organic additives are described and compared to those typical of common Cr(VI) plating bath. It is shown that thick nanocrystalline chromium–carbon deposits may be obtained from the Cr(III) electrolytes under study, with some physicochemical and service properties of such coatings exceeding those of “usual” chromium deposits. The proposed trivalent chromium baths are distinguished by their high current efficiency and electrodeposition rate. The covering power of the Cr(III) baths is poorer than in case of hexavalent chromium baths; it may be improved by applying basic chromium sulfate (chrome tanning agent) instead of chromium sulfate as a source of Cr(III) ions in solution. There is no need to utilize toxic lead anodes in Cr(III) deposition processes. It is noted that a grave shortcoming of trivalent baths is their low conductivity in comparison with the hexavalent ones. 相似文献
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同时采用小槽和Hull Cell试验,并结合稳态极化法、电势阶跃法以及SEM等测试手段,研究了光亮剂对全硫酸盐体系中三价铬电沉积行为的影响.结果表明:光亮剂的光亮效果是一个综合效应,而不是一种光亮剂的作用结果;在E<-0.10 V的区间内,光亮剂能明显地增大阴极极化;光亮剂的加入,使镀液在4.00~22.50 A/dm2区域内能得到光亮的镀层;并且光亮剂的加入不会改变三价铬镀铬的电沉积行为,与未加光亮剂时一样仍遵循瞬时成核机理. 相似文献
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直流电沉积纳米晶铁-镍-铬合金箔工艺、性能及其机理研究 总被引:1,自引:0,他引:1
在含三价铬的水溶液中,以氨基乙酸(gly)为配位剂,直流电沉积制备出Fe-Ni-Cr合金箔,研究了电流密度、铬盐浓度对合金箔成分的影响;采用扫描电子显微镜和X射线衍射对合金箔进行表征,并对合金箔的各项性能进行了研究;采用电化学方法对铬电沉积机理进行初探.确定直流电沉积Fe-Ni-Cr合金箔的最佳工艺条件为:电流密度为15A/dm2,铬盐质量浓度为50 g/L,温度为60℃,pH值为1.5.在此条件下可获得厚度为20~30 μm光亮、无裂纹的合金箔,其中Cr、Fe和Ni的质量分数分别为4%~6%、60%~65%、30%~35%.合金箔微观形貌为紧密堆砌的不规则板块状小晶粒;合金箔为纳米晶结构,晶粒尺寸在纳米范围内,主相是Cr与α-Fe或γ-Fe形成的间隙固溶体;合金箔中Cr含量提高,硬度、电阻及耐蚀性均随之提高.通过理论计算gly-Cr3+还原沉积的标准活化能为35.6kJ/mol,该过程由电子转移步骤控制. 相似文献
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电沉积分布的均匀性涵盖了沉积层厚度、合金成分、微观结构(晶粒)及材料性能等多个方面,是电沉积技术应用中需要解决的重要问题.为此,简述了阴极电沉积分布的均匀性及形成原理,介绍了改善沉积分布均匀性可以采取的主要措施及其研究现状,总结了研究过程中所采用的几种方法. 相似文献
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V.S. Protsenko F.I. DanilovV.O. Gordiienko S.C. KwonM. Kim J.Y. Lee 《Thin solid films》2011,520(1):380-383
A sulfate trivalent chromium bath is described which contains chromium(III) salt, sodium sulfate, aluminum sulfate, boric acid, formic acid, carbamide and surfactant. The bath is operated using either titanium-manganese dioxide anodes or platinized titanium anodes without separation of anodic and cathodic compartments. Effect of bath composition and electrolysis conditions on current efficiency of chromium electrodeposition was studied. At optimal bath composition and electrolysis conditions, the deposition rate does not practically change during electrolysis time; it is close to 0.8 μm min−1. The nanocrystalline coatings with a thickness of several tens of micrometers are bright and smooth. The value of Cr-coatings hardness does not substantially differ from that observed in case of Cr(VI)-based baths. The possibility of continuous service of the proposed trivalent chromium bath was confirmed by means of a durational electroplating test (~ 2 months). 相似文献
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装饰性三价铬电镀层难以增厚、镀液不稳定、色泽不能令人满意.为此,采用线性电位扫描法探讨了甲酸铵、乙酸铵、草酸铵、柠檬酸铵4种羧酸盐配位剂体系中镀光亮镍钢表面电还原三价铬的极化特征,开发了草酸铵和甲酸铵复合配位剂三价铬电镀工艺,并对铬镀层的主要性能进行了研究.结果表明:草酸铵配位能力较强.可作为三价铬电镀的配位剂,甲酸铵既是配位剂也是消除六价铬干扰的还原剂,两者复配加入三价铬电镀液,可以获得较好的镀铬层,其厚度可达1.0~1.3 μm,光亮度为2级,耐蚀性、结合力等性能良好,能够满足装饰用途要求. 相似文献
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脉冲电沉积法制备纳米材料的研究进展 总被引:1,自引:0,他引:1
纳米材料具有特殊的磁性、光学、力学、电学、电化学催化等性能,而脉冲电沉积技术在制备纳米材料方面应用广泛且优点多.着重列举了脉冲电沉积技术在制备纳米晶材料、纳米复合材料、纳米析氢材料、纳米金属薄膜及纳米金属多层膜、纳米线材料等方面的应用,总结了纳米材料的一些特点,展望了脉冲电沉积技术制备纳米材料的前景. 相似文献
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Effluent discharged from the chromium electroplating industry contains a large number of metals, including chromium, copper, nickel, zinc, manganese and lead. The ion exchange process is an alternative technique for application in the treatment of industrial wastewater containing heavy metals and indeed it has proven to be very promising in the removal and recovery of valuable species. The main objective of the present work is to evaluate the performance of commercial ion exchange resins for removing chromium trivalent from industrial effluents, and for this purpose two resins were tested: a chelating exchange resin (Diaion CR11) and a weak cationic resin (Amberlite IRC86). In order to evaluate the sorption capacity of the resins some equilibrium experiments were carried out, being the temperature and pH the main variables considered. The chromium solutions employed in the experiments were synthetic solutions and industrial effluents. In addition, a transient test was also performed as an attempt to understand the kinetic behaviour of the process. 相似文献