TC4钛合金低磷化学镀工艺研究

针对TC4钛合金低磷化学镀,在浸锌活化和乳酸-乙酸络合条件下,对镍磷质量浓度比、温度、pH值、乙酸、乳酸等工艺因素对镀速和镀层磷含量的影响进行系列实验研究。用扫描电镜、能谱仪、显微硬度仪、X射线衍射仪对镀层的表面形貌、硬度和物相进行表征。研究结果表明：提高镍磷质量浓度比、温度、pH值,控制络合剂乳酸在20g/L～22g/L,乙酸在19g/L～20g/L范围内,均有利于低磷镀层的形成,平均镀速为25.6μm/h;镀层为晶态的Ni-P过饱和固溶体,平均粒径10μm,磷含量为2.56wt%,硬度为750.2HV.     

铜/镍磷合金复合镀涤纶电磁屏蔽织物的制备

在化学镀铜涤纶织物表面电镀镍磷合金,制备铜/镍磷复合镀电磁屏蔽织物,研究了硫酸镍浓度、氯化镍浓度和亚磷酸浓度对复合镀织物性能的影响.结果表明,电镀镍磷合金工艺为:硫酸镍浓度240 g/L,氯化镍浓度40 g/L,亚磷酸浓度30 g/L,制备的铜/镍磷复合镀织物表面镀层均匀致密,在300 k~3 000 MHz电磁屏蔽效能在90 dB以上,具有优异的电磁屏蔽效能、抗氧化性和耐蚀性.     

光亮镀镍添加剂对镀层抗腐蚀性能的影响研究

设计正交试验,研究了镀镍光亮剂糖精钠、1,4-丁炔二醇和香豆素对镍镀层的光亮度及抗腐蚀性能的影响。通过对镀层表观形貌、微观形貌、电荷转移电阻、自腐蚀电位、自腐蚀电流的分析,确定了光亮镀镍的组合光亮剂最优水平。综合考虑镍镀层的光亮效果和电化学抗腐蚀性能,最优的组合光亮剂添加水平为:糖精钠0.8g/L、1,4-丁炔二醇0.6g/L、香豆素0.25g/L。     

硫酸亚铁铵盐弱酸性体系电镀锌铁合金的研究

以硫酸亚铁铵盐和氯化锌为主盐的弱酸性体系电镀锌铁合金,镀液静置15d,仍稳定、无沉淀。研究了添加剂、电流密度、温度和pH对镀层的外观以及镀层组成的影响。结果表明,增加添加剂的用量,降低温度或者电流密度,会使镀层变得光亮。pH对镀层光亮度的影响有一个最佳范围为4．50．5。添加剂用量为15-17mL／L,温度为30oC,pH为4．5-5,电流密度为0．5—1．0A／dm‘时,镀层光亮且铁含量在0．2％__0．8％。SEM图显示,添加剂用量的增加使得镀层的结构更加紧密。     

珍珠镀镍的电镀工艺参数优化

通过正交试验确定了珍珠镀镍的最佳工艺条件,制备出了效果优良的珍珠镍镀层,提高了镀层的珠光外观和耐腐蚀性．通过金相显微镜照片和电化学技术表征（交流阻抗技术和Tafel曲线测试）对单层珍珠镀镍、单层光亮镀镍和双层珍珠镀镍（光亮镍上施镀珍珠镍）的性能进行了对比．结果表明：双层珍珠镀镍更加均匀致密;单层珍珠镍的耐腐蚀性优于双层珍珠镀镍;双层珍珠镀镍的耐腐蚀性优于单层光亮镀镍．     

化学镀法制备钴包覆碳化硅复合粉末的研究

采用化学镀法制备钴包覆碳化硅复合粉末,通过研究化学镀过程中钴盐浓度、还原剂浓度、络合剂浓度、缓冲剂浓度、温度以及pH值等因素对沉积速率的影响规律,得到化学镀钴的优化条件。利用XRD、SEM和EDAX等测试手段对该复合粉末的组分及形貌进行了表征。实验和表征结果表明,当硫酸钴浓度为30～50g/L,次磷酸钠浓度为40g/L,柠檬酸钠浓度为60～70g/L,控制温度为50～70℃以及调节pH值等于8时,镀层沉积速度较快,所得粉体表面被钴均匀包覆。     

双向脉冲电镀银对抗变色能力的影响

以银层抗变色特性为主要指标，对双向脉冲光亮镀银的工艺参数进行了优选，最佳脉冲参数为：频率８００Ｈｚ、正向占空比为１０％、负向占空比为零。在最佳参数下得到的银镀层光亮平滑，抗变色能力优良，与直流光亮镀银相比较，抗变色性能提高１０％以上。     

金刚石表面化学镀铜工艺研究

研究以硼氢化钠为还原剂、硝酸银为活化剂的金刚石表面化学镀铜工艺。使用XRD和EDS分析金刚石表面镀层的结构与成分,讨论渡液组分和工艺条件对化学镀铜的影响,并用体式显微镜观察了金刚石表面镀铜后的形貌。得到的最佳镀液配方与工艺条件是:NaBH41.5g/L,CuSO4·5H2O 20g/L,酒石酸钾钠15g/L,EDTA-2Na 20g/L,亚铁氰化钾65mg/L,双联吡啶15mg/L;溶液pH值13,反应温度60℃。结果表明运用本工艺可以在金刚石表面获得均匀的镀铜层。     

铝基复合材料基底镀厚膜TiN的附着力研究

利用直流磁过滤多弧离子镀技术在铝基复合材料基片上镀制大于25μm的TiN厚膜.对厚膜TiN的附着力及其与各种工艺条件的关系.采用扫描电镜对厚膜TiN的微观结构及划痕形貌进行了分析.研究结果表明:基片的清洗、基片的温度、孤电流、脉冲偏压和镀层界面组织结构等都影响厚膜TiN的附着力;弧电流为70A、脉冲偏压为100V、占空比为70%、温度为200℃时,厚膜TiN的临界载荷达到4.5kg/mm~2,远大于指标要求4kg/mm~2;镀层界面的融合有利于提高厚膜TiN的附着力.     

木材表面化学镀Ni—P电磁屏蔽材料的制备和性能

采用正交实验法进行了木材表面化学镀Ni-P合金的研究,并对镀层进行了表征和电磁屏蔽性能的测试。实验结果表明,最优化学镀工艺条件为:ρ(NiSO4)=35 g.L-1,ρ(NaH2PO2.H2O)=45 g.L-1,ρ(HOOCCH2CH2COOH)=40 g.L-1,ρ(HOOCCHOHCH2COOH)=40 g.L-1,温度65℃,pH6.8。制备的Ni-P镀层平整、光亮,电磁屏蔽效能随Ni金属沉积量的增加而提高。在Ni沉积量12.79~38.38 g/m2的实验范围内,制备的新材料的电磁屏蔽效能为30.85~54.32 dB。     

Effect of attapulgite added in plating bath on the properties of Ni/TiC nano-composite coatings

Pure copper plates were coated by Ni-TiC dipulse current plating method. The effects of adding different concentration(ranging from 0.5 g/L to 3.0 g/L) of attapulgite nano particles to the plating bath on the surface morphology, wear resistance, and oxidation resistance of Ni/TiC/Attapulgite nano-composite coatings were investigated. The experimental results show that the composite coating is flat and compact with adding 3.0 g/L in the bath, and the coating preferred orientation is changed from the planes (111) to (200). The coefficient of the composite coatings decreases from 0.68 to 0.18 with increasing content of attapulgite in the bath, a mixed mode of adhesive-abrasive wear occurs for all coatings, and the wear mechanism shows a transition from adhesive-abrasive to predominantly abrasive wear mechanism when the concentration of attapulgite is beyond 1.5 g/L in electrolyte. The oxidation resistance of composite coatings is the best prepared when adding attapulgite particles at 0.5 g/L in the bath, the oxide mainly consists of a NiO phase by X-ray analysis.     

氯化铵体系Zn－Ni合金电镀

研究了镀液成分和工艺参数对镀层Ｎｉ含量的影响，探讨了Ｚｎ－Ｎｉ合金共沉积机理，获得了耐蚀性为同等镀锌层６倍以上的光亮Ｚｎ－Ｎｉ（１３％）合金电镀的配方和工艺条件．     

Ni-P/Al_2O_3复合镀层性能的表征与测试

为了提高镀层的耐磨性和硬度,在45碳钢基材上实施Ni-P/Al2O3化学复合镀,使纳米Al2O3微粒均匀分布于Ni-P基体中.研究了化学复合镀工艺条件和镀液组分对镀层性能的影响.镀件的耐蚀性实验和XRD分析表明:当硫酸镍25 g/L,次亚磷酸钠30 g/L,纳米Al2O3微粒加入量为5 g/L,乳酸20 mL/L和柠檬酸5 g/L,在pH=5.5,施镀温度为(85±2)℃,获得的Ni-P/Al2O3复合镀层表面光滑、胞状物致密,镀层的耐腐蚀性较高、硬度可达600HV,有利于得到综合性能较高的镀层.     

Morphology and tribological properties of Ni/n-SiO_2 composite coatings by pulse-reverse current brush-plating

1INTRODUCTION Pulse reversecurrent(RC)platingisanew technologycomingwithpulsecurrent(PC)andre versecurrent.Onthisaspect,earlierstudiesmani festedthat[16],intheconditionofRC,theeffectofelectricdoublelayerwasrestrained,thecontrol ofcrystallinegrowthwasenfor…     

Effect of direct current and pulse plating on the EDM performance of copper-zirconium diboride composites

Direct current and pulse plating of copper-zirconium diboride (ZrB2) composites were studied and the effects of current density (DC) and pulse duty cycle (PC) on the EDM performance of the composites were investigated. With increasing current den- sity, the effect of grain refinement on the electro-discharge machining (EDM) performance of the composites compensates that of the decrease of ZrB2 content in the composites, which improves the spark-resistance of the material. Under the same average current density and other experiment conditions, a lower duty cycle yields better EDM performance probably because more ZrB2 particles are incorporated in the composites in this condition. However, at a still lower duty cycle (10%), the particle agglomeration and the microcracks of the copper matrix occur, which considerably deteriorate the spark-resistance of the composites.     

Technology of black coloring for stainless steel by electrochemical method

The technology of black coloring for stainless steel by electrochemical method was studied. The optimum bath compositions and operating conditions were obtained as follows. 40 - 50 g/L K2Cr2O7, 15 - 20 g/L MnSO4, 15 -20 g/L （NH4）2SO4, 20 -40 g/L H3BO3, 20 -30 g/L additive A, 2 g/L （NH4）6Mo7O24 ; time 9 -20 min; temperature 15 - 30 ℃ ; potential 3 V and current density 1 - 2 mA/cm^2. The effects of the compositions of the bath on the quality of black colored film were discussed. The influences of passivation process on the black coloring velocity and performances of black colored film layer were investigated. The results show that the passivation process can improve the corrosion resistance and the stability to bear color-change; （NH4）2 SO4 can control the black coloring velocity and prolong black coloring bath life remarkably; and additive A can improve the evenness and compactness of black colored film layer. The results of scanning electron microscopy and energy dispersive spectra show that the microstructure is of cylindrical lump, the filling process can decrease the crackles, and the main elements of black colored film are Fe, Cr, Mn and Ni.     

激光熔覆Ni+Cr_2O_3复合涂层的耐蚀性

研究了激光搭接熔覆Ni+Cr2 O3复合涂层在 0 .5mol/LH2 SO4 +0 .5mol/LNaCl水溶液中的电化学行为 .试验表明Cr2 O3粒子在激光熔池中发生了完全溶解 ,涂层具有胞状枝晶组织特征 .激光熔覆Ni+Cr2 O3复合涂层比单一熔覆Ni合金涂层和 2Cr13马氏体不锈钢基材具有更低的维钝电流密度和更宽的钝化区范围 ,明显改善了在该腐蚀介质中的抗点蚀能力 .     

等离子喷涂NiCr/Cr_2C_3、Ni/C及其复合涂层的耐磨性能

为了加强车辆机械零件的表面防护,采用等离子喷涂工艺在304N不锈钢表面分别制备了NiCr/Cr_2C_3涂层、Ni/C涂层以及NiCr/Cr_2C_3和Ni/C复合涂层,观察了涂层组织形貌,测试了涂层硬度和耐磨性,分析了涂层的摩擦磨损机理.结果表明,3种涂层中NiCr/Cr_2C_3和Ni/C复合涂层的耐磨性能最好.金属粘结相NiCr可以起到足够的支撑作用,从而防止涂层剥离与黏着磨损的产生.Ni/C作为固体润滑剂,通过自润滑作用降低了涂层的整体摩擦系数.