共查询到19条相似文献,搜索用时 156 毫秒
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以硝酸银代替氯化钯为活化剂在空心微珠表面化学镀Ni-P合金镀层,用X射线衍射仪(XRD)、能谱仪(EDX)、扫描电镜(SEM)、X射线光电子能谱(XPS)和振动样品磁强计(VSM)对其进行了分析表征,结果表明以硝酸银代替氯化钯为活化剂,在空心微珠表面能得到Ni-P合金镀层.并分析了以硝酸银代替氯化钯为活化剂制备Ni-P镀层的形成机理. 相似文献
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采用粉体化学镀技术,以AgNO3取代常见的贵金属盐PdC12作为活化剂、H2PO2-取代Sn2+作为还原剂,经一步前处理过程,在空心微珠表面包覆NiCoP合金.利用扫描电镜、能谱分析仪分别讨论包覆层的形貌和成分,表明NiCoP合金均匀包覆在空心微珠表面;X射线衍射和磁强计分析表明,未经热处理的包覆合金涂层为非晶态结构,无明显的铁磁性;经热处理后的包覆合金涂层转变为晶态结构,表现出较强的铁磁性,有利于吸收电磁波.最后,提出了这种改进工艺的一种可能的机理. 相似文献
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为了改善镀液性能,扩大Ni-Co-P合金的应用范围,以硼酸为缓冲剂,柠檬酸钠为配位体化学镀Ni-Co-P合金,用扫描电镜(SEM)、差示扫描量热(DSC)和X射线衍射(XRD)等技术研究了Ni-Co-P合金镀层表面的微观形貌和晶化行为.结果表明,Ni-Co-P合金镀层在镀态时呈多晶态结构,有立方Ni-Co合金相和非晶相(以非晶相为主),镀层于339.4℃时转化为Ni3P相,其晶化行为与氨性缓冲介质中得到的Ni-Co-P合金有明显差异.Ni-Co-P合金在镀态时其表面有许多直径为1.9~4.8μm的圆形小颗粒;500℃处理后的镀层表面有一些直径为6~7μm的圆形大颗粒,表面呈胞状结构,每一胞状物由许多50~100nm的颗粒形成.本研究为Ni-Co-P合金应用提供了参考. 相似文献
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空心玻璃微珠表面化学镀Ni-P合金磁性涂层的研究 总被引:2,自引:0,他引:2
采用化学镀工艺在空心玻璃微珠表面包覆了一层磁性的Ni-P合金涂层,对其进行了表面金属化改性.分别用X射线衍射仪(XRD)、傅立叶变换红外光谱仪(FT-IR)、扫描电子显微镜(SEM)以及振动样品磁强计(VSM)对化学镀前后空心玻璃微珠的形貌、组成、结构以及磁性能进行了表征.结果表明:通过化学镀工艺制备的Ni-P合金涂层由原子团簇组成;涂层为非晶结构并具有较好的磁性能;化学镀后空心玻璃微珠的X射线衍射强度和红外透射强度均降低. 相似文献
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为了改善化学镀Ni-Co-P合金工艺存在的镀速慢、镀层质量差等问题,研究了镀液组分、表面活性剂、pH值、稳定剂、配位剂对化学镀Ni-Co-P合金镀层沉积速度、耐蚀性、孔蚀率的影响,得出最佳镀液配方和工艺:26 g/L CoSO4,28 g/L NiSO4,22 g/L NaH2PO2,80 g/L Na3C6H5O7,69 g/L(NH4)2SO4,1 mg/L KI,50 mg/L十二烷基苯磺酸钠,pH=8,温度85℃.本研究结果为化学镀Ni-Co-P合金工艺提供了依据,较有实用价值. 相似文献
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通过改变化学镀液中金属离子Co2+与(Co2++Ni2+)的摩尔浓度比获得了不同的Ni-Co-P合金化学镀层。研究了钴的引入对Ni-Co-P合金镀层的沉积速率及组织性能的影响。结果表明:随着Co2+与(Co2++Ni2+)摩尔浓度比的增加,镀层的沉积速率不断下降,镀层中P含量逐渐减小,镀层表面的胞状组织由大到小;镀层硬度随Co2+与(Co2++Ni2+)摩尔浓度比的增加先升高后降低,Co2+与(Co2++Ni2+)摩尔浓度比为0.4时,硬度最大达554.12HV,镀层具有优良的耐硫酸腐蚀性能,Co2+与(Co2++Ni2+)摩尔浓度比为0.6时,镀层耐蚀性最强。 相似文献
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Electroless nanocrystalline Ag coating of fly ash cenosphere particles utilizing a Sn-Pd catalyst system is demonstrated in this article. The deposition of pure metallic nanocrystalline Ag on the fly ash cenosphere particle surface is confirmed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) analysis. Under the described conditions of electroless coating, average nanocrystalline Ag-coating thickness is observed to be approximately 220 nm, using a focused ion beam technique, which is less than that observed by transmission electron microscopy (TEM) (260-360 nm). TEM observation further reveals that the Ag-coating is made up of 50 nm Ag nanocrystallites, which is comparable with the size of approximately 37 nm obtained from the XRD data. The mechanism of the electroless Ag-coating process is discussed. Ag-coated fly ash particles find applications in manufacturing conducting polymers for electromagnetic interference shielding applications. 相似文献
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采用化学镀方法制备Ni-Co-P三元合金镀层以改善NdFeB磁体的耐腐蚀性能.优化了镀液配方以及施镀工艺,研究了镀液pH值和金属离子配比([Co2 ]/[Ni2 Co2 ])对沉积速度和镀层成分的影响,测量了NdFeB基体和不同镀层在3.5%(质量分数,下同)NaCl溶液中的极化曲线.结果表明,随镀液pH值增加,沉积速度提高,镀层中Co含量升高,Ni含量和P含量逐渐降低;随镀液中Co2 比例增加,沉积速度下降,镀层中Co含量升高,Ni和P含量降低.化学镀Ni-Co-P合金后的NdFeB磁体在3.5%NaCl溶液中的腐蚀速度降低了约两个数量级;当镀液金属离子配比[Co2 ]/[Ni2 Co2 ]=0.3时,镀层耐腐蚀性能最好,且优于相同施镀条件下所得到的Ni-P镀层. 相似文献
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锅炉炉管的水垢或磨损不利于锅炉的安全节能,在炉管内外表面制备不同的Ni—P化学镀层和Ni—P—PTFE化学复合镀层,具有耐磨且低表面自由能性能,防水垢防磨损,安全节能效果明显。在化学镀Ni—P合金基础上加入PT—FE粒子,采用镍盐和还原剂在同一溶液中进行的自催化氧化-还原反应,从而在工件表面沉积出的Ni—P—PTFE化学复合镀层,具有低表面自由能,且具有高的硬度、耐磨性、润滑性、优异的耐蚀性。PTFE浓度、表面活性剂、温度和pH值,对Ni—P—PTFE化学复合镀层PTFE含量和PTFE粒子分散性有影响。 相似文献
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化学镀Ni-Co-W-P及其析氢性能的研究 总被引:1,自引:0,他引:1
用化学镀方法制备出Ni-Co-W-P合金电极,测量了其在1 mol/L NaOH溶液中的阴极极化曲线并研究了其析氢电催化活性.试验表明,在相同的电流密度下,Ni-Co-P,Ni-W-P和Ni-Co-W-P合金电极的析氢过电位较Fe电极降低,其中Ni-Co-W-P的析氢过电位降低约230 mV,XRD试验显示其镀层为非晶态.并进一步测试了其在7 mol/L KOH中的连续电解曲线.结果表明:Ni-Co-W-P合金电极比Ni-Co-P,Ni-W-P合金电极具有更好的析氢电催化活性和电化学稳定性,有利于降低槽压,减少能耗. 相似文献
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Z. Wu Q. N. Wang S. Zhao Y. Zhang C. M. Yang 《Materialwissenschaft und Werkstofftechnik》2023,54(3):312-326
In this paper, the epoxy resin composite filled with wood fiber and fly ash cenosphere was prepared. In order to improve the bonding properties between wooden fiber/fly ash cenosphere and epoxy resin, the grafting treatment of wooden fiber and fly ash cenosphere surfaces was carried out here using KH550 type silane coupling agent. The effects of different process parameters on the surface modification effect of wooden fiber and fly ash cenosphere were investigated, the mechanical properties and energy absorption characteristics of the materials before and after the filler modification were tested, and the microscopic interfacial structures of the matrix with wooden fiber and fly ash cenosphere were investigated by scanning electron microscopy. Meanwhile, based on LS-DYNA simulation software, the energy-absorbing performance of energy-absorbing boxes prepared from AA6061 aluminum alloy and modified wooden fiber-fly ash cenosphere/epoxy resin composites were compared in low-velocity collisions. 相似文献
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The feasibility of incorporating fly ash cenospheres in die cast magnesium alloy has been demonstrated. The effects of fly ash cenosphere additions on the microstructure and some of the salient physical and mechanical properties of magnesium alloy (AZ91D) metal matrix composites were investigated. The control AZ91D alloy and associated composites, containing 5, 10, and 15 wt.% of fly ash cenospheres (added), were synthesized using a die casting technique. A microstructural comparison showed that microstructural refinement – occurred due to the fly ash additions and became more pronounced with an increase in the percentage of the fly ash added. The metal matrix areas nearer to the fly ash particles exhibited a greater degree of refinement than was observed in the areas further away from these particles. Both filled and unfilled fly ash cenospheres, and porosity were observed in the composite microstructures. The composite specimen densities decreased and the coefficient of thermal expansion did not change significantly as the volume percent of fly ash was increased within the range investigated. The hardness values of the composite specimens exhibited an increase in proportion to the increase in percentage of added fly ash. The tensile strength of the composites also increased as the concentration of fly ash cenospheres was increased. In contrast, the Young’s modulus of these composite samples, as measured by non-destructive pulse-echo method, decreased as the percentage of fly ash in the composite was increased. SEM micrographs of the tensile fracture surfaces showed broken cenospheres on the fracture surface and evidence of ‘pull outs’, where fly ash particles were previously embedded in the matrix. Compression testing results showed that the presence of 5 wt.% cenospheres decreased the compressive strength and compressive yield strength of the composite relative to that of the AZ91D matrix alloy. Surprisingly, a significant change in compression strength was not observed for the composites with 10 and 15 wt.% cenospheres in comparison to the AZ91D matrix alloy. In contrast to the tensile tests, no cenosphere remnants were observed on the compressive test fracture surface of the composites. This observation suggests that the fracture of the composite was initiated within the AZ91D matrix by normal void nucleation and growth, followed by crack propagation through the matrix, avoiding any of the cenospheres, leading to composite fracture of the matrix. 相似文献