温度对AZ31B镁合金表面化学镀Ni-B合金性能的影响

试验研究了镀液温度对AZ31B镁合金表面化学镀Ni-B合金性能的影响。结果表明:镀液温度对化学镀Ni-B合金的镀速、成分、形貌、耐腐蚀性有很大的影响,当温度为80℃时,镀速较大,镀层均匀、紧凑、细小,耐腐蚀性良好。     

主盐对镁合金表面化学镀Ni-B合金性能的影响

主要研究镀液中主盐浓度对镁合金表面化学镀Ni-B合金性能的影响,着重探讨主盐浓度对镀速、镀层形貌及耐腐蚀性的影响.结果表明:当氯化镍浓度为30g/L时,镀速最大且镀层组织均匀、紧凑、细小,耐腐蚀性较好.     

还原剂对铝表面化学镀Ni-Co-P合金耐腐蚀性能的影响

研究镀液中还原剂浓度对铝表面化学镀Ni-Co-P合金性能的影响。运用增重法分析了浓度对镀速的影响;采用JSM-5610LV型扫描电镜、能谱仪、CHI660C型电化学工作站研究化学镀Ni-Co-P合金的表面形貌、微观成分和耐腐蚀性能。结果表明,镀液中还原剂浓度为30 g/L时,镀速最大,镀层均匀、紧凑、细小,镀层的镍、钴含量适中,耐腐蚀性较好。     

还原剂浓度对铝合金表面化学镀Ni-P-SiC的影响

试验研究了还原剂浓度对1060铝合金表面化学镀Ni-P-SiC的影响,着重探讨不同还原剂浓度对镀速和镀层形貌、成分及耐腐蚀性的影响,并得出还原剂的最佳浓度。结果表明,当还原剂浓度为24 g/L时,镀速最大,镀层均匀、紧凑、细密、耐腐蚀性良好。     

化学镀Ni-B合金镀层性能

通过改变镀液还原剂的含量和加入定量的乙酸钠,研究对化学镀镍硼合金形貌和性能的变化。从晶体结构、镀层形貌、硬度和耐磨曲线等几方面来分析加入乙酸钠12g/L时,化学镀Ni-B合金镀层形貌和性能改善的原因。乙酸钠起到缓冲剂的作用,降低了化学镀Ni-B的镀速,提高了化学镀Ni-B的致密度,改善了镀层的质量从而提高镀层的各种性能。     

担载非晶态Ni-B合金催化材料化学镀法制备

以NH3为稳定剂,KBH4为还原剂,考察了化学镀法制备γ-Al2O3担载Ni-B非晶态合金催化剂工艺条件.NH3浓度和温度对镀液的稳定性有显著影响,加料顺序亦影响催化剂制备的顺利进行.14℃下,NH3浓度13.5%,镀液稳定时间8 h,当NH3浓度降到5.4%时,稳定剂完全失去作用.当温度升到30℃,NH3浓度13.5%,镀液稳定时间降到3.5 h.在γ-Al2O3表面预载微量金属镍敏化载体表面,可以催化化学镀的顺利进行.XRD数据显示化学镀法制备Ni-B合金的非晶态特性明显优于普通化学还原法.     

担载非晶态Ni-B合金催化材料化学镀法制备

以NH3为稳定剂,KBH4为还原剂,考察了化学镀法制备γ-Al2O3担载Ni-B非晶态合金催化剂工艺条件.NH3浓度和温度对镀液的稳定性有显著影响,加料顺序亦影响催化剂制备的顺利进行.14℃下,NH3浓度13.5%,镀液稳定时间8 h,当NH3浓度降到5.4%时,稳定剂完全失去作用.当温度升到30℃,NH3浓度13.5%,镀液稳定时间降到3.5 h.在γ-Al2O3表面预载微量金属镍敏化载体表面,可以催化化学镀的顺利进行.XRD数据显示化学镀法制备Ni-B合金的非晶态特性明显优于普通化学还原法.     

铝硅合金表面复合化学镀(Ni-B)-SiC的研究

研究了在铝合金(LG12)表面上复合化学镀(Ni-B)-SiC镀层工艺,对影响镀层镀速的几大因素进行了探讨,确定在铝硅合金上复合化学镀(Ni-B)-SiC的最佳工艺及相关参数.同时对该工艺下获得的复合镀层结构性能进行了研究.结果表明,分散相SiC的嵌入基本没有改变Ni-B基质合金原有的非晶结构.450℃热处理后,复合镀层向晶体结构转变,镀层硬度值HV14737,达到最大.     

还原剂对镁合金表面化学镀Ni-P合金性能的影响

通过镀速测量、SEM、EDS等方法研究了AZ31B镁合金的化学镀Ni-P合金工艺。结果表明:镁合金表面化学镀Ni-P合金的最佳还原剂为次磷酸钠,还原剂的最佳浓度为20 g/L。所制备的镀层耐腐蚀性能良好。     

化学镀Ni—B合金工艺研究

近年来,化学镀Ni-B合金层的优异功能特性越来越受到各国化学镀工作者的重视,但它在我国还是个空白.本文详细讨论了二甲氨基硼烷化学镀Ni-B镀液中各种成分和工艺条件对Ni-B合金沉积速度和镀层含硼量的影响,确定了柠檬酸铵做配位剂的二甲氨基硼烷化学镀Ni-B合金的最佳工艺条件。按此条件可以稳定地获得含硼量为1～5％的Ni-B镀层。     

Effect of coating bath composition on the properties of electroless nickel-boron films

The effect of borohydride, thallium acetate, ethylenediamine and sodium hydroxide concentrations, and the coating bath temperature on both the coating rate and boron content of the electroless Ni-B films was investigated systematically. The Ni-B coating rate increased with the increase in thallium acetate and sodium hydroxide concentrations, but it was not very sensitive to the borohydride concentration. Below 90 g L^− 1 ethylenediamine concentration the coating efficiency was significantly low and above this value as the ethylenediamine concentration increased the coating rate decreased slightly. Below 85 °C the coating rate was very low and above this temperature it was insensitive to the bath temperature. The boron content of Ni-B film increased with the increase in the borohydride concentration and the bath temperature, and decreased with the increase in thallium acetate and ethylenediamine concentrations. Up to 50 g L^− 1 sodium hydroxide concentration, the boron content of the film increased and above this concentration it was insensitive to the sodium hydroxide concentration. As the boron content of Ni-B film increased, both the corrosion resistance and microhardness of Ni-B film increased. Heat treatment brought significant improvement in the microhardness but the corrosion resistance of Ni-B film was observed to decrease due to the disappearance of the amorphous characteristics of the as-deposited Ni-B film and the formation of the Ni-B compound phases.     

镁合金直接化学镀Ni-B镀层的腐蚀电化学行为研究

  研究了镁合金表面化学镀Ni-B合金的电化学行为,采用电化学动电位扫描极化曲线和交流阻抗研究了Ni-B镀层的腐蚀电化学行为,结果表明,Ni-B镀层在3.5%NaCl溶液中具有优良的耐蚀性能.所得Ni-B镀层的自腐蚀电位在－400 mV左右,相对于基体-1460 mV提高了1000 mV,自腐蚀电流密度小于0.7 μA/cm²,相对于基体28.5 μA/cm²降低了近两个数量级,说明Ni-B镀层能够有效地提高AZ91D 镁合金的耐腐蚀性能,使AZ91D镁合金在35%NaCl溶液腐蚀介质中的腐蚀速度明显降低.电化学交流阻抗测试结果符合极化曲线的测量结果,化学镀Ni B镀层后的AZ91D镁合金在3.5％NaCl溶液中的阻抗值相对于基体提高两个数量级,表现为自腐蚀电流降低,阻抗值相应提高.     

化学镀Ni-B和Ni-B/BN镀层微动磨损性能研究

采用化学镀液相沉积技术,以钛合金TA7为基体材料,分别镀覆Ni-B合金镀层和Ni-B/BN自润滑复合镀层,对镀层进行微动磨损性能测试和镀层表面形貌观察.结果表明:在微动磨损过程中完全滑移状态下,Ni-B/BN镀层中六方BN微粒具有类似石墨层状结构,该Ni-B/BN镀层具有自润滑性能,使其摩擦因数比Ni-B镀层低,即Ni-B/BN复合镀层在滑移区耐微动磨损性能要优于化学镀Ni-B二元合金镀层.     

工况条件对化学镀镍硼合金层耐磨性的影响

本文研究了载荷和配对材料对化学镀镍硼合金层耐磨性的影响。结果表明:镀层的磨损量随载荷的增加而加大;配对材料的硬度愈高,镀层的磨损量愈大。     

主盐浓度对铝合金表面化学镀Ni-Co-P的影响

试验研究了主盐浓度对铝合金表面化学镀Ni-Co-P的影响。着重探讨不同主盐浓度对镀速和镀层形貌、成分及耐腐蚀性的影响,并得出主盐的最佳浓度。研究结果表明,当主盐浓度为15g/L时,镀速最大,镀层均匀、紧凑、细密、耐腐蚀性良好。     

Ni-B合金电沉积工艺性能研究

研究了Ni-B合金电沉积的镀液、镀层性能.阴极极化曲线实验结果表明Ni-B合金电沉积是典型的诱导共沉积类型.镀液稳定性高,镀层硬度高,镀态硬度值可达700～800HV,耐磨性好.镀层具有一定的耐酸能力和很强的耐碱液腐蚀能力.     

A novel dual nickel coating on AZ91D magnesium alloy

Magnesium alloys covered with metal coating display excellent corrosion resistance,wear resistance,conductivity and electromagnetic shielding properties.The electroless plating Ni-P as bottom layer following the electroplating nickel as surface layer on AZ91D magnesium alloy was investigated.The coating surface morphology was observed with SEM and the structure was analyzed with XRD.Electrochemical tests and salt spray tests were carried out to study the corrosion resistance.The experimental results indi...     

Formation and properties of stannate conversion coatings on AZ61 magnesium alloys

The effects of solution composition and temperature on the microstructure and corrosion resistance of stannate conversion coatings on AZ61 magnesium alloys were investigated. The conversion coating consisted of a porous layer as under layer intimately contacted with the magnesium plate and a hemispherical particle layer as major overlay formed right on top of the porous layer. During the coalescence of the hemispherical particles to form a complete coating on the magnesium alloy, some sites of discontinuity inevitably left and determined the corrosion resistance of the coating evaluated using a salt spray test. Increasing bath stannate ion concentration and lowering bath pH increased the population density of the hemispherical particles whose size was accordingly reduced. The corrosion resistance of the conversion coating was improved with finer particles, which were preferably formed at less alkaline solution with higher stannate ion contents. Furthermore, the conditions favoring the formation of finer particles also reduced the immersion time necessary for producing the conversion coating with optimal corrosion resistance.     

Influence of potassium pyrophosphate in electrolyte on coated layer of AZ91 Mg alloy formed by plasma electrolytic oxidation

The effect of potassium pyrophosphate in the electrolyte on plasma electrolytic oxidation (PEO) process for AZ91 Mg alloy was investigated. The morphologies and chemical compositions of the coating layer on the AZ91 Mg alloy were evaluated and corrosion resistance was also estimated by potentiodynamic polarization analysis. The coating layer on AZ91 Mg alloy coated from the Bath 2 containing 0.03 mol/L of potassium pyrophosphate for 360 s exhibited considerably dense structure and contained 11%–18% (mass fraction) of phosphorous. The higher content of phosphorous of coating layer coated from Bath 2 could be detected at the bottom of oxide layer, which strongly implied that the phosphorous ion might be concentrated at the barrier layer. Corrosion potential of coating layer of AZ91 Mg alloy increased and corrosion current density decreased with increasing the concentration of potassium pyrophosphate. The polarization resistance (R_p) of coating layer of AZ91 Mg alloy coated from Bath 2 was 4.65×10⁷ Ω/cm², which was higher than that (R_p=3.56×10⁴ Ω/cm²) of the sample coated from electrolyte without potassium pyrophosphate. The coating layer coated from Bath 2 containing 0.03 mol/L potassium pyrophosphate exhibited the best corrosion resistance.