共查询到19条相似文献,搜索用时 140 毫秒
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电沉积方法对Ni-SiC纳米微粒复合镀层结构与性能的影响 总被引:2,自引:0,他引:2
分别采用磁力搅拌-直流电沉积法、超声波搅拌-直流电沉积法和超声波搅拌-脉冲电流沉积法制备Ni-SiC纳米微粒复合镀层,并探讨电沉积方法对复合镀层组织结构、显微硬度、耐磨性及耐蚀性的影响。结果表明:超声波搅拌能引发扰动搅拌和击碎分散等综合效应,对共沉积过程起到积极促进作用,明显改善复合镀层的形貌组织,提高硬度、耐磨性和耐蚀性;并且进一步替代加载脉冲电流后,脉冲电流和超声波的作用叠加,使电沉积制备的复合镀层表面更平整,结构更致密,硬度更高,耐磨性和耐蚀性也更好。 相似文献
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脉冲技术电沉积铅镉合金的研究 总被引:1,自引:0,他引:1
通过对氨基磺酸盐体系中铅、镉产铅-镉镀液的阴极化曲线的研究,结果表明镀液中加入添加剂间苯二酚,显著增加电极化及改善镀层性能;用脉冲电沉积代替常规直流电沉积铅-镉,结果表明,脉冲电沉积所得镀层质量上流法有明显改善;原子吸收分光光度法测定表明,直流电沉积和脉冲电沉积可以得到不同含量的铅镉合金镀层。 相似文献
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采用直流电沉积方法在镀液中加入复合有机添加剂制备了镍铁纳米合金镀层。利用扫描电镜分析镀层形貌及晶粒尺寸,研究了硫酸亚铁铵浓度、电流密度、pH值对镀层中铁含量的影响,测定了镀层的耐腐蚀性能及结合力。结果表明,该纳米镀层表面致密、平整,且结合强度、耐腐蚀性能优良。 相似文献
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直流、周期换向脉冲纳米复合镀层在WM-2005-1型摩擦磨损试验机上,考察其摩擦磨损性能.采用扫描电镜观察镀层及磨损表面形貌,分析磨损机理.结果表明,周期换向脉冲复合镀层的形貌、耐磨性能优于直流复合镀层;载荷和转速对两种复合镀层的摩擦磨损性能有很大影响. 相似文献
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《Ceramics International》2020,46(2):1775-1783
The hard wear-resistant nanocomposite Ti–Al–Ni–C–N coatings were deposited by direct current magnetron sputtering (DCMS) and high power impulse magnetron sputtering (HIPIMS) in the Ar, Ar+15%N2, and Ar+25%N2 atmospheres. The structure of coatings was analyzed using the X-ray diffraction analysis, glow discharge optical emission spectroscopy, and scanning electron microscopy. Mechanical and tribological properties were measured using the nanoindentation and scratch testing as well as by tribological testing using the “pin-on-disc” scheme. Electrochemical corrosion resistance and oxidation resistance of coatings were investigated. The results suggest that the coatings are based on the FCC phases TiCN and Ni3Al with crystallites size ~3 and ~15 nm, correspondingly. DCMS coatings with optimal composition were characterized by hardness 34 GPa, stable friction coefficient <0.26 and wear rate <5 × 10-6 mm3N-1m-1. Application of HIPIMS mode allowed the increase of adhesion strength, tribological properties and corrosion resistance of coatings. 相似文献
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The durability and mechanical properties of epoxy ester coatings and films has been improved by blending with rigid aromatic polyurea (PU). The interaction of PU and epoxy ester was enhanced by coupling the polymers with polymethylhydrosiloxane. The reactions between various entities are analyzed by Fourier transform infrared spectroscopy and the change in physical and mechanical properties are studied by a dynamic mechanical analyzer. The corrosion resistance of the hybrid coatings was measured by direct current polarization method, direct current polarization (DCP). The addition of polymethylhydrosiloxane enhances the corrosion properties in the hybrid coatings. The surface morphology was analyzed by scanning electron microscopy. The glass transition temperature of the films increases with increasing PU concentration and a wide glass rubber transition range for hybrid coatings was achieved which confirms the higher impact strength of the hybrid coatings and films. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
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Evaluation of the corrosion resistance of phosphate coatings obtained by anodic electrochemical treatment 总被引:1,自引:0,他引:1
S. Jegannathan T.S.N. Sankara Narayanan K. Ravichandran S. Rajeswari 《Progress in Organic Coatings》2006,57(4):392-399
The corrosion resistance of phosphate coating obtained by anodic electrochemical treatment at 4–6 mA/cm2 is addressed in this paper. The corrosion performance of these coatings is also compared with the coatings obtained by chemical treatment. The regenerated phosphoric acid under the influence of anodic current causes a large variation in morphological features of the coatings. Immersion and salt spray tests indicate the ability of these coatings to act as a barrier film on mild steel. Polarization and electrochemical impedance spectroscopic (EIS) studies indicate that the corrosion resistance of phosphate coatings obtained by anodic treatment decreases with increase in current density employed for deposition. In spite of their higher coating weight, the corrosion resistance of phosphate coatings obtained by anodic treatment is inferior to those obtained by chemical treatment. The porosity or discontinuities created due to the dissolution of the coating under the influence of anodic current are considered responsible for the inferior corrosion resistance of these coatings. The study concludes that anodic treatment has only a limited scope for preparing phosphate coatings with improved corrosion resistance. 相似文献
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Aluminum nitride (AlN) coatings of about 2 μm thick were deposited on mild steel (MS) by means of direct current (DC) reactive
magnetron sputtering. AlN coatings were prepared in an Ar + N2 gas mixture and their crystal structure, microstructure, and topography were analyzed by X-ray diffractometry (XRD), scanning
electron microscopy (SEM) and atomic force microscopy (AFM), respectively. XRD revealed that the films are polycrystalline
in nature and have a hexagonal wurtzite structure with a predominant peak observed along the (002) plane. SEM and AFM images
showed the presence of continuously covered pebble like spherical grains on the surface. These coatings showed lower coefficient
of friction and excellent wear resistance compared to the bare MS substrate. The potentiodynamic polarization studies showed
lower corrosion current density and higher polarization resistance for the AlN/MS structure than the uncoated MS substrate. 相似文献
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脉冲电沉积纳米镍-碳化硅复合镀层的性能 总被引:1,自引:0,他引:1
分别采用直流(DC)和换向脉冲电流(PRC)电沉积法制得纳米Ni-SiC复合镀层。采用X射线衍射仪、扫描电镜、能谱仪对比研究了纯Ni镀层和Ni-SiC复合镀层的微观结构、宏观残余应力、表面形貌及成分。用浸泡法研究了不同镀层在3.5%(质量分数)NaCl和10%(体积分数)H2SO4溶液中的腐蚀行为。结果表明,脉冲电沉积能改变镀层的微观结构,有效提高镀层硬度,降低宏观残余应力。脉冲电沉积所得到的纯Ni镀层和纳米Ni-SiC复合镀层在3.5%NaCl及10%H2SO4溶液中的耐蚀性均优于直流镀层。脉冲镀层在3.5%NaCl溶液中受腐蚀很轻,主要腐蚀形态为点蚀,而在10%H2SO4溶液中,SiC粒子作为增强相使镀层的耐腐蚀性进一步提高。 相似文献
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M. Zemanová M. Krivosudská M. Chovancová V. Jorík 《Journal of Applied Electrochemistry》2011,41(9):1077-1085
Ni–W alloy coatings were prepared on a mild steel substrate by means of pulse current (PC) and compared to the coatings electrodeposited
by direct current (DC). In particular the study dealt with the influence of the frequency using pulse current on the surface
morphology while maintaining a constant duty cycle. A constant charge for DC and PC electrodeposition of Ni–W alloy coatings
was used. The morphology of the coatings was explored by scanning electron microscopy and the composition of the coatings
was analysed by X-ray powder diffraction and energy dispersive X-ray analysis. Corrosion resistance of Ni–W alloy coatings
was investigated by potentiodynamic polarization in a chloride medium. The corrosion products were analysed by Raman spectroscopy.
It was found that the temperature of the electrolysis affects current efficiency of the DC and PC electrodeposition. The frequency
of pulse electrodeposition alters the morphology of the Ni–W alloy coatings. There was evidence of the positive influence
of increased tungstate concentration in the electrolyte on corrosion resistance of the Ni–W alloy coatings. 相似文献