Ni-P-纳米化学复合镀层制备工艺的研究

为提高化学复合镀层的性能,采用纳米（SiC）r制备Ni-P-纳米（SiC）p化学复合镀层,较系统地研究镀液配方及各工艺参数对Ni-P-纳米（SiC）r化学复合镀层的影响,分析相应机理,同时对镀层进行热处理比较。实验结果表明：主盐、还原剂、温度、pH值、搅拌速率及（SiC）p加入量对Ni-P-（SiC）p镀层的沉积速率有较大影响,实验确定的最佳主盐浓度为28g/L、还原剂浓度为30g／L、施镀温度为（85±1）℃、pH值为4．5、搅拌速度为200r／min、（SiC）p加入量为2g／L。     

Ni-Al2O3复合镀层工艺研究

采用正八棱柱体形状的阴极,在普通的瓦特型镀液中加入氧化铝颗粒制备复合镀层,研究了阴极电流密度、搅拌速度和颗粒在镀液中的浓度等因素对镀层内粒子含量与阴极不同方向之间的关系。实验结果表明,阴极电流密度、搅拌速度和镀液中Al2O3含量都对镀层中复合粒子的含量有明显的影响,总体趋势是与阳极距离近的方向,粒子含量多,且各个位向之间的含量随工艺条件的不同而变化。     

一种节能阴极材料的制备条件研究

对在铁基体上进行复合电镀镍的制备条件进行了研究,讨论了镍粉悬浮量,镀液pH值,电流密度,镀液温度,电镀时间等工艺条件和参数对复合镀层的表面沉积量和表面镀层结合力的影响,通过实验确定了最佳电镀条件,电极耐酸腐蚀性强,析氢电位比纯铁下降260 mv左右,电极结构稳定成本低,制备简单,用于氯碱工业和水电解工业.     

Ni/纳米Al2O3微粒复合电镀工艺的试验研究

采用复合电镀的方法在45#钢表面制备获得Ni/纳米Al2O3微粒复合镀层.利用正交试验法研究了电流密度、镀液pH值和镀液温度对Ni/纳米Al2O3微粒复合镀层性能和沉积过程的影响.结果发现,它们对镀层沉积过程及其性能都有影响,但影响的程度和规律不同.最后综合考虑各因素,制订出Ni和纳米Al2O3微粒在45#钢表面发生共沉积的较理想工艺.     

Ni-SiC纳米复合电镀工艺研究

针对镀液中阴极电流密度、镀液温度以及极板间距,对Ni-SiC纳米复合镀层显微硬度的影响进行了研究.采用正交实验法对各工艺参数进行了优选.并且利用扫描电镜（SEM）对复合镀层的表面形貌及截面形貌进行了观察和分析.结果表明,Ni-SiC纳米复合镀层较纯镍镀层表面平整光滑,显微组织均匀、致密,并且其显微硬度也有明显提高.     

纳米Cr颗粒对Ni-Mo复合镀层性能的影响

为了研究纳米Cr颗粒对Ni-Mo复合镀层性能的影响,采用脉冲电沉积方法制备具有不同Cr含量的Ni-Mo复合镀层.利用扫描电子显微镜和X射线衍射仪分别观察和分析复合镀层的组织形貌及结构.采用电化学测试和X射线光电子能谱研究复合镀层的析氢性能和耐蚀性能.结果表明:随着镀液中纳米Cr颗粒含量的增加,镀层晶粒得到细化,析氢过电位增大,复合镀层析氢性能得到提高;当镀液中纳米Cr颗粒含量为20 g/L时,复合镀层表面钝化膜中MoO₃含量较高,且可与Cr产生协同效应,因而复合镀层具有较好的耐蚀性能;但随着镀液中纳米Cr颗粒含量的进一步增加,复合镀层中沉积的Cr元素含量降低,复合镀层的析氢性能和耐蚀性能均降低.因此,当镀液中纳米Cr颗粒含量为20 g/L时,复合镀层具有较好的析氢性能和耐蚀性能.     

由沉积纳米晶体镍

利用恒电沉积的方法，在55－65℃，pH值小于3．5，电流密度大于5A/dm^2含有糖精的瓦特液中分别以直流和脉冲方法镀取镍。经X射线衍射分析，镍晶体沉积层表现为（111）择优取向，扫描电镜和能谱分析结果显示，所得的镍晶晶粒尺寸为小于10nm的纳米晶体，并且镀层中含有少量的硫。通过研究电流密度及溶液中糖精浓度对镍沉积速率的影响，发现电流密度低时，镍沉积速率与电流密度呈线性关系，糖精的加入使镍沉积允许的电流密度增大，沉积速率减慢，对镍沉只起增加极化作用。     

电沉积Ni-Co-Cr合金镀层及其耐蚀性研究

采用电化学恒电流技术在铜基体上沉积制备了Ni-Co-Cr三元合金镀层,研究了电流密度、温度及pH值对合金镀层成分的影响.利用SEM和EDS研究了Ni-Co-Cr合金镀层的形貌与成分,通过交流阻抗技术研究了镀层的耐蚀性.采用弯曲实验法测定了镀层的结合力.结果表明,在阴极电流密度为100 mA/cm2,镀液温度为25℃,pH为2.5条件下沉积的合金镀层致密均匀,化学组成中Cr含量达到最高(达到10％,该成分为10.22％ Cr,21.61％ Ni,59.86％ Co,质量分数,氧和铜含量未计入),具有优化耐蚀性.     

焦磷酸盐镀铜工艺研究

通过铜镀层做基体材料的中间层或底层,可以获得许多具有特殊性能的镀层。氰化镀铜是应用最为广泛的底层镀铜工艺,但是氰化镀液中含有剧毒物。焦磷酸盐镀铜是替代氰化镀铜的最重要电镀工艺,但它的最大缺点在于附着力不好。文章用电化学方法研究了工艺条件对焦磷酸盐镀铜的镀层性能（特别是结合力）影响。结果表明：镀液的温度、搅拌速度、电流密度直接影响镀层性能;最佳工艺条件为：温度45~C,时间60rain,搅拌速度200r／rain,阴极电流密度1．5A／dm2。本研究结果为焦磷酸盐镀铜提供了实用的参考价值。     

化学镀Ni-P-Si3N4复合镀层在柴油机气缸套和活塞环上的应用

船用柴油机的气缸套和括塞环是常见的易损件，为了提高其耐磨性和抗咬合性，在气缸套和活塞环表面上进行化学复合镀Ni—P-Si3N4，研究了还原剂、镀液pH值、镀液温度对沉积速度的影响，分析了复合镀层的性能。实验表明：Si3N4颗粒在镀层中的弥散强化作用，提高了复合镀层的硬度和耐磨性，从而延长了气缸套和活塞环的使用寿命，达到节省燃料费用的目的。     

Effects of Surfactants SDS and CTAB on Ni-SiC Deposition

The influences of surfactant type and concentration on the content and uniformity of SiC particles in Ni-SiC deposit were studied in this paper. The electrochemical behavior of preparing Ni-SiC composite coating was investigated using the cyclic voltammetry method. Then the impact of surfactants on the deposition potential of Ni-SiC coating was analyzed. Electrochemical studies showed that the cathode overvoltage increases gradually with increasing SDS (Sodium dodecyl sulfate) concentration. The CV curve showed the shift towards a lower current at a given potential with increasing SDS concentration. Ni-SiC composite coatings were prepared by electrodeposition. The experimental results show that the dispersion of 40nm SiC in Ni-SiC coating obtained in the electrolyte containing SDS is superior that containing CTAB (cetyltrimethyl ammonium bromide). CTAB increases the content of 40 nm SiC particles in the Ni-SiC coating, but the uniformity of 40 nm SiC particles in Ni-SiC composite coating is poor. SiC particles are still agglomerated. Compared with the anionic surfactant SDS and the cationic surfactant CTAB, surfactant SDS makes the particles better dispersed. But the contribution of surfactant SDS for co-deposition amount of SiC particles is negligible. The cationic surfactant CTAB can effectively improve the suspension performance of SiC particles and promote the co-deposition of SiC particles and metallic nickel. But there is still some reunion of SiC.     

Electroless copper-phosphorus coatings with the addition of silicon carbide （SiC） particles

Cu-P-silicon carbide(SiC)composite coatings were deposited by means of electroless plating.The effects ofpH values,temperature,and different concentrations of sodium hypophosphite(NaH2PO2·H2O),nickel sulfate(NiSO4·6H2O),sodium citrate(C6H5Na3O7·2H2O)and SiC on the deposition rate and coating compositions were evaluated,and the bath formulation for Cu-P-SiC composite coatings was optimised.The coating compositions were determined using energy-dispersive X-ray analysis(EDX).The corresponding optimal operating parameters for depositing Cu-P-SiC are as follows:pH 9; temperature,90℃; NaH2PO2·H2O concentration,125 g/L; NiSO4·6H2O concentration,3.125 g/L; SiC concentration,5 g/L; and C6H5Na3O7·2H2O concentration,50 g/L.The surface morphology of the coatings analysed by scanning electron microscopy(SEM)shows that Cu particles are uniformly distributed.The hardness and wear resistance of Cu-P composite coatings are improved with the addition of SiC particles and increase with the increase of SiC content.     

镍—碳化硅复合共沉积的研究

报道在船用汽缸材料上进行Ni—SiC复合镀的研究。探讨了SiC浓度、液温、溶液PH和电流密度对沉积量的关系。获得了结合力强、硬度高、分散性好的镀层。利用微电泳技术测量体系中SiC微粒ξ电位,初步讨论了共沉积机理。     

电化学合成甲基磺酸亚锡的工艺研究

采用离子隔膜电解法制备了甲基磺酸亚锡,探讨了电流密度、体系温度、电解液浓度和搅拌速率各试验因素对电解过程的影响规律．通过单因素试验得出了各因素的最佳值：甲基磺酸浓度1mol／L,电流密度4A／dm^2,体系温度30℃,搅拌速率230r／min．该工艺操作简单、无毒、无害、无三废排放,产品产率高,是一种环境友好的绿色工艺．     

Morphology analysis of nickel-boron/diamond electroless deposition

The influences of mass concentration of nickel chloride hexahydrate, sodium borohydride, ethylenediamine, pH value, bath temperature on deposition rate were studied with orthogonal experiments by a series of pre-treatments on micro-diamond particle, and the optimized parameters were obtained. Both the morphology and the composition of original diamond and the diamond with Ni-B coating were analyzed by SEM and XRD respectively. The SEM image shows that the spherical Ni-B particle is coated upon diamond. XRD pattern shows that the coating compositions are Ni and Ni2B.     

Electric-oxidation extraction of molybdenite concentrate in alkaline NaCl electrolyte

The dissolution of molybdenite concentrate in NaCl electrolyte was investigated. The results show that the dissolution rate increases with the increase in liquid-to-solid ratio, stirring speed, NaCl concentration and temperature. When the liquid-to-solid ratio is 30:1, stirring speed is 400 r/min, concentration of NaCl is 4 mol/L at pH=9 and room temperature, the leaching efficiency of molybdenite concentrate will reach 99.5% in 240 min. Molybdenite concentrate cannot be electro-oxidized directly on the anode. The kinetic studies show that the dissolution of molybdenite concentrate is represented by shrinking core model with diffusion through a porous product layer of element sulfur, and the apparent activation energy for the dissolution reaction is 8.56 kJ/mol.     

Electric-oxidation extraction of molybdenite concentrate in alkaline NaCl electrolyte

The dissolution of molybdenite concentrate in NaCl electrolyte was investigated. The results show that the dissolution rate increases with the increase in liquid-to-solid ratio, stirring speed, NaCl concentration and temperature. When the liquid-to-solid ratio is 30:1, stirring speed is 400 r/min, concentration of NaCl is 4 mol/L at pH=9 and room temperature, the leaching efficiency of molybdenite concentrate will reach 99.5% in 240 min. Molybdenite concentrate cannot be electro-oxidized directly on the anode. The kinetic studies show that the dissolution of molybdenite concentrate is represented by shrinking core model with diffusion through a porous product layer of element sulfur, and the apparent activation energy for the dissolution reaction is 8.56 kJ/mol.     

CVD法快速制备SiC过程分析

采用TMS（CH3SiCl3)为原料,H2为载气,Ar为稀释气,在1000－1200℃范围以内以石墨为基体,通过化学气相沉积法（CVD）制备地SiC块体材料,在特定的工艺条件下,SiC的生长速率可达0．6mm/h,结合实验结果,研究了常压SiC-CVD过程中,对SiC生长速率产生影响的若干因素的作用,初步探索了基体尺寸与沉积室尺寸的比例、沉积温度、稀释气流量以及沉积时间对沉积速率的影响,综合分析提高了SiC生长速率的原因。