Development of copper coatings on molybdenum powders by electroless plating technique

Mo powders with average particle size of 3 μm were attempted to coat with copper by electroless plating technique. The effect of the solution composition and plating conditions on the electroless copper plating was studied. The uncoated and coated powders were subjected to the microstructural studies by SEM and the phases were analyzed by XRD. The results indicate that the Mo powders are coated with copper, at （he same time, Mo-Cu composite powders with Cu content ranging from 15% to 85% （mass fraction） can be obtained. The optimal values of pH, HCHO concentration and temperature are in the ranges of 12-13, 22-26 ml/L and 60-65℃, respectively. The diffusion-shrinkage autocatalytic model is suggested for the growth mechanism of electroless coating over the surface.     

Preparation and characterization of molybdenum powders with copper coating by the electroless plating technique

Molybdenum powders with a diameter of approximately 3 μm were coated with copper using the electroless plating technique in the pH 12.5-13 and temperature range of 55-75℃.The optimization of the electroless copper bath was evaluated through the combination of process parameters like pH and temperature.The optimized values of pH and temperature were found to be 12.5 and 60℃,respectively,which attributes to the bright maroon color of the coating with an increase in weight of 46%.The uncoated and coated powders were subjected to microstructural studies using scanning electron microscope (SEM) and the phases were analyzed using X-ray diffraction (XRD).An attempt was made to understand the growth mechanism of the coating.The diffusion-shrinkage autocatalytic model was suggested for copper growth on the molybdenum surface.     

化学镀法制备Ni-P包覆SiC复合粉

用次亚磷酸钠作为还原剂,采用化学镀的方法制备表面包覆Ni-P镀层的Si C复合颗粒,其表面形貌、成分、结构、电磁波吸收性能分别利用SEM、EDS、XRD及矢量网络分析仪进行了研究。结果表明:经二次镀镍后Si C表面形成了一层连续且致密的Ni-P合金镀层,并且没有引入其它杂质元素。随着施镀时间的延长镀层不断增厚。化学镀镍工艺显著改善了Si C对电磁波的吸收能力,镀后复合颗粒在4~22 GHz频段范围内,超过-5 d B的吸收带宽高达11.8 GHz,最大吸收出现在17.7 GHz处,衰减值为-9.9 d B。     

简化预处理辅助化学镀制备Cu包覆TiC复合粉末

研究了一种简化预处理辅助化学镀工艺制备Cu包覆TiC复合粉末.利用场发射扫描电子显微镜和能谱仪分析了原始TiC粉末,预处理之后的TiC粉末,Cu包覆TiC复合粉末的表面形貌和成分,同时也阐述了Cu镀层的生长机理.结果表明,经过简化预处理之后的TiC出现了很多表面缺陷,Cu能够均匀的包覆在TiC颗粒表面.其生长机理如下:经过预处理之后的TiC出现很多表面缺陷,成为化学镀过程中的活性点;化学镀过程中,Cu在TiC表面的各个缺陷处形核长大;Cu与Cu之间相互接触相互作用形成密集的网状结构最终形成致密的Cu镀层.     

超声波辅助化学镀法制备CoAl_2O_4尖晶石粉体

采用超声波辅助化学镀法在室温条件下制备了Co/Al2O3复合粉体,1200℃下热处理1.5h获得了CoAl2O4尖晶石粉体。用扫描电镜、透射电镜和X射线衍射测定了粉体的微观形貌、成分和相组成;用差热分析法确定了粉体的尖晶石转变温度。结果表明:镀覆制备的Co/Al2O3复合粉体由金属钴和Al2O3两相组成,金属钴相包覆Al2O3相,Co包覆层在Al2O3颗粒表面分布均匀且结构较疏松;复合粉体的尖晶石转变温度为850℃左右;转变后获得的粉体也是一种复合粉体,由Al2O3和CoAl2O4两相组成,由粉体的生长机制可预见,它是以α-Al2O3为核心CoAl2O4尖晶石包覆在其表面的结构。     

Ni-P化学镀的机理及其研究方法

Ni-P化学镀镀液体系复杂,影响因素甚多,因此多种Ni-P化学镀机理理论共存,综述并评价了目前流行的几种化学镀的机理理论,同时介绍了其研究方法.     

Ni-P-Nanodiamond composite electroless plating

The effect of nanodiamond content in electrolyte and rotational speed of the stirrer on the deposition rate of coatings,the nanodiamond content in coatings,the microstructure and the micro-hardness of coatings were studied.A self-made pin-on-disk tribo-meter was employed to evaluate the wear resistance of prepared coatings.Results show that the thickness of composite coating decreases with the rotational speed,while the micro hardness of coating and the content of nanodiamond in coating increase with increa...     

化学镀制备玄武岩纤维/镍核壳结构及其表征

采用简单易行的化学镀方法，在较低的温度下制备出一种新型的玄武岩纤维／镍核壳结构。SEM、XRD、XPS分析结果表明，金属Ni颗粒吸附在玄武岩纤维表面，形成了一层均匀连续的镍壳层。通过对试验结果进行分析，得出了制备玄武岩纤维／镍核壳结构的最佳温度和pH值分别为50℃和10．0。文中对化学镀核壳结构的形成机理也进行了初步分析。     

Surface characterization and electrical resistivity of electroless plating nanocrystalline copper films on glass

Nanocrystalline copper films were prepared on the glass by electroless plating technique. The surface characterization of copper films with different deposition time was studied by field emission scanning electron microscopy （FESEM） and atomic force microscopy （AFM）. The results indicate that the copper films have a （111） texture. A continuous and smooth film forms on the glass substrate at deposition times of 5 min. The surface roughness of as-deposited copper films becomes rougher with large nodules as the deposition time increases. According to Fuchs-Sondheimer （F-S）, Mayadas-Shatzkes （M-S） theory and a combined model, the grain boundary reflection coefficient （R） is calculated in the range of 0.40-0.75. The theoretical analysis based on the experimental results show that the grain boundaries contribute mainly to the increase of electrical resistivity of nanocrystalline copper film compared with the film surfaces.     

纳米Al2O3p化学镀铜复合粉末的烧结致密化

化学镀是制备纳米颗粒增强金属基复合材料的有效方法.对纳米Al2O3p化学镀铜粉末的烧结致密化特点进行了研究,分析了化学镀粉末的预处理、成型压力、烧结温度、保温时间、复压复烧工艺等对致密化的影响.在优化各影响因素的情况下,对Al2O3含量为10%的化学镀铜粉末采用常规粉末冶金工艺得到了相对致密度达94%的试样.     

Process of electroless plating Cu-Sn-Zn ternary alloy

1 Introduction Electroless plating tin and tin alloy is an attractive technique to produce function plating layer with prior performances of corrosion resistance and decoration[1, 2], due to the possibility of uniform deposition on complex shapes, conduct…     

Ni-B合金化学镀包覆TiB2粉的研究

为改善TiB2粉末物性,采用化学镀工艺对其进行包覆Ni—B合金处理。经Hall流动仪检测,包覆后粉末松装密度由1．15～1．17g／cm^3增加到1．38～1．39g／cm^3,粉末流动性由包覆前粉末堵塞霍尔流动性测量仪喷嘴变为94～97s／50g;SEM形貌扫描分析表明包覆效果较好,包覆率大于90％;补加镀液包覆效果更好,镀层更致密,包覆率大于95％。     

镍-磷-钛酸钾晶须化学复合镀层的制备及性能

采用化学复合镀方法制备镍-磷-钛酸钾晶须复合镀层,用扫描电镜和金相显微镜观察复合镀层的表面形貌和断面结构,用XRD研究时效温度对镀层组织结构的影响,并解释时效温度对镀层显微硬度的影响机制。采用交流阻抗技术和中性盐雾实验研究镀层的耐腐蚀性能。在销-盘式摩擦磨损试验机上进行复合镀层的摩擦磨损性能测试。结果表明：镀层的显微硬度随温度的变化曲线呈单峰形态,在400℃时达到最大值;复合镀层具有良好的耐腐蚀性能和摩擦磨损性能,在同等实验条件下,复合镀层的磨损率只有Ni-P镀层的1/4。     

化学镀Ni-Co-P合金的初期沉积行为

用特殊制样手段在ＴＥＭ上直接观察镍钴磷合金化学沉积的初期形貌。结果表明：化学沉积的初期沉积过程具有明显的择优倾向和不均匀性。原子并非以单个原子的形式沉积于基体表面,而是还原后的原子在固－液界面处首先形成原子团,然后基体表面的高能量区域优先沉积。阴着时间的延长,沉积闰的长大颂向并不明显,而是以沉积颗粒逐步链状联结的方式扩展,直至覆盖整个基体表面。     

Diffusion bonding of a superplastic inconel 718SPF superalloy by electroless nickel plating

Although intimate contact can be obtained for diffusion bonding of a superplastic Inconel 718SPF superalloy under a low pressure of 7 MPa, the precipitates formed at the interface retarded achievement of a sound joint. The shear strength was only 41.5 MPa for an overlap length of 12 T (T=1.3 mm, sheet thickness). The diffusion bondability of this Inconel 718SPF superalloy was enhanced by electroless nickel plating. In this situation, the bonding shear strength increased to 70.4 MPa for the same overlap length of 12 T under the same bonding condition, regardless of the roughness of the surface to be bonded. Upon decreasing the overlap length from 12 to 6 T, the bonding strength remained constant.     

热处理对化学镀镀层性能影响的研究进展

热处理可以使镀层稳定,改善力学性能。分别叙述了随温度的升高和保温时间的延长,热处理对化学镀Ni-P二元合金、Ni-W-P、Ni-Cr-P等三元合金、Ni-W-Mo-P四元合金镀层性能的影响,分析了热处理对合金镀层耐蚀性、耐磨性的影响,并提出了热处理改善化学镀镀层性能的研究方向。     

化学镀和粉末冶金法制备W/Cu梯度热沉材料

用化学镀法和粉末冶金的方法制备高致密的W/Cu梯度热沉材料。用场发射扫描电镜观察了材料的组织结构、界面和断口形貌。对材料的机械性能也进行了表征,如抗弯强度和显微硬度。结果表明材料每一层都很致密且组织结构均匀。从截面上材料成分呈梯度分布,每层之间没有明显的界面。三层W/Cu梯度热沉材料的相对密度可达99.2%。散热层、过渡层和封接层的显微硬度值分别是200、210和240 HV。抗弯实验结果所示封接层和散热层作为承重抗弯表面时的抗弯强度分别是428.5MPa和480.7MPa。     

化学镀制备Ni-Cu-P-TiN复合镀层及其热处理工艺

采用中温化学复合镀在高碳钢表面制备了Ni-Cu-P-TiN复合镀层,采用SEM、XRD对镀层的相组成与微观结构进行了分析,并研究了400℃热处理时间对镀层相组成、硬度、耐腐蚀性能的影响。结果表明,TiN相均匀的分散于Ni-Cu-P胞状结构的界面之间,沉积比例在4.5%~5.0%;在400℃下进行恒温热处理,随时间延长,Ni-Cu-P-TiN镀层中逐渐析出细小Ni3P相,截面硬度增加,40min时达到最高硬度960HV;随热处理时间继续延长,Ni3P相的晶粒粗化,镀层硬度下降;镀态Ni-Cu-P-TiN镀层的自腐蚀电流密度为7.92μA,仅为高碳钢(167μA)的1/20,经400℃下恒温热处理0~40min,其自腐蚀电流密度逐渐升高,40min时达到最大值28.2μA。     

Regeneration and decontamination of a nickel citrate complex in spent electroless nickel plating solutions

The possibility of citrate precipitation by excess metal ions in alkaline solutions suggests the use of Ni(II) together with OH^? to precipitate a Ni(II)-citrate complex from spent electroless plating solutions. After treatment of the precipitate with acid, excess Ni(II) can be removed in the form of insoluble Ni(OH)₂. The solution of the Ni(II)-citrate complex can then be reused for electroless nickel plating. During this procedure the additive adipate is not regenerated. For decontamination of spent electroless nickel plating solutions Fe(III) can be used as Ni(II)-citrate complex precipitant.