cBN微粒粒径及含量对Ni-cBN复合镀层结构及高温耐磨性的影响

目的 探究立方氮化硼cBN微粒粒径及含量对复合电沉积的影响,提升Ni-cBN复合镀层的高温耐磨性.方法 在镀液中添加不同粒径(～0.5、3.0、10μm)及不同含量的cBN颗粒制备Ni-cBN复合镀层,采用溶解称重法测试镀层复合量,通过扫描电镜(SEM)、显微硬度计和高温球盘磨损试验等评价不同复合镀层的微观结构、硬度及高温耐磨性.结果 cBN微粒粒径为0.5μm时,颗粒易发生轻微团聚,复合量难以大幅度提高;选择3.0μm和10μm的cBN颗粒,一定程度上利于提高复合量.整体上说,复合量越高、微粒粒径越大,复合镀层的平均硬度越高.但在相近复合量下,3.0μm颗粒复合的镀层颗粒分布均匀性更佳.相比于纯Ni层,Ni-cBN复合镀层中弥散分布的cBN颗粒,提高了镀层硬度,改善了镀层的耐磨性.对于不同粒径的颗粒,小颗粒(～0.5μm)复合的镀层的摩擦系数略低,但粘着磨损较为严重;大颗粒(～10μm)复合的镀层的粗糙度较高,以磨粒磨损为主.结论 镀液中cBN微粒的粒径及含量直接影响镀层复合量及耐磨性.选择粒径为3.0μm的cBN颗粒、控制cBN复合量为40.5％时,Ni-cBN复合镀层的显微硬度>600HV,且高温耐磨性更佳.     

工艺参数对Ni-ZrO2纳米复合镀层性能的影响

用电沉积方法在铜表面制备了Ni-ZrO2纳米复合镀层。研究了工艺参数对复合镀层的硬度、耐磨性、耐蚀性的影响。结果表明,镀层硬度随阴极电流密度、镀液温度的增大均呈现先增大后减小的趋势;而随镀液中纳米ZrO2的添加量增加,镀层的硬度逐渐增大;镀层的耐磨性随这几个工艺参数的增加先增加后减小;镀层的耐蚀性随着电流密度的升高先下降再升高,随着镀液中纳米ZrO2添加量、镀液温度的增加,镀层的耐蚀性先升高再下降。本工作中最佳的工艺参数为纳米ZrO2添加量8g/L,阴极电流密度3A/dm2,镀液温度50℃左右。     

抛光轮耐磨复合镀层制备及其性能研究

以不锈钢为基体材料,Ni-W-P为基质合金,添加耐磨微粒碳化硅(SiC)和六方氮化硼(-αBN)固体润滑微粒,在抛光轮工作面镀制Ni-W-P/SiC BN多元复合镀层。该工艺得到的Ni-W-P/SiC BN多元复合镀层表面光亮、质感均匀、镀层结合力良好、耐蚀性优良。经过相同次数磨损试验,Ni-W-P/SiC BN热处理镀层的耐磨性能是0Cr18Ni9Ti不锈钢的5.22倍。     

长效自润滑耐磨耐蚀复合镀层制备工艺及性能研究

以长效自润滑耐磨、耐蚀复合镀层制备技术,采用45#钢为基体材料、Ni-B为基底合金、Ni-W-P为基质合金、添加耐磨人造金刚石微粒和固体润滑剂(CF)n微粒,镀制Ni-B和Ni-W-P/金刚石-(CF)n双层复合镀层。试验结果表明:该工艺得到的Ni-B和Ni-W-P/金刚石-(CF)n双层复合镀层表面光亮,质感均匀,粗糙度为Ra0.2;镀层结合力良好;耐蚀性优良;经过相同次数磨损试验,磨损量仅为未镀试件的21.2%。     

热处理对Ni-P-PTFE化学复合镀层性能的影响

向一种含有络合剂的化学镀镍液中加入ＰＴＦＥ浓缩乳液,在材料表面获得了Ｎｉ－Ｐ－ＰＴＦＥ化学复合镀层,研究了热处理工艺对Ｎｉ－Ｐ－ＰＴＦＥ 事氐层性能的影响。试验结果表明,在３００℃以下加热时,复合镀层的硬度变化不明显。加热温度为４００℃时,复合镀层具有最高的显微硬度,耐磨性增加,结合强度提高,热处理后,复合镀层的耐蚀性下降。     

电刷镀复合镀层工艺及性能研究

对电刷镀复合镀工艺以及镀层性能作了深入的研究,通过研制的一种高粘度胶状刷镀Ｎｉ溶液,解决了固体微粒悬浮的均匀性和稳定性问题,在此种镀液为基础添加各种不同的固体微粒,制备出复合镀液,并施以电刷镀工艺,从而得到各种不同性能的复合镀层。     

复合镀层电刷镀工艺的研究

在电刷镀溶液中加入一定量的一种或几种不溶性的固体非金属颗粒,通过电刷镀工艺的沉积而获得硬度较高,耐磨,耐蚀,自润滑的复合镀层,在天龙４＾＃－４快速镍刷镀液及天龙６＾＃－６非晶态镍磷合金镀液的基础上,就其镀液组成,添加剂等条件进行试验,选择,并对加入的固体颗粒的分散数量,颗粒径的大小进行试验,确定工艺参数,形成完善可行工艺。     

比浊法测定Ni-W复合镀层中微粒的含量

用比浊法测定了（Ni-W)-SiC、(Ni-W)-ZrO、(Ni-W)-BaSO4复合镀层中微粒的含量,确定并讨论了测定的最佳条件。方法的相对偏差小于4．0％,回收率为96．0％－103．0％。     

稀土对复合镀工艺及镀层性能的影响

研究了稀土对复合镀工艺及性能的影响，结果表明，添加适量的稀土能显著地提高复合镀层中ＳｉＣ微粒的含量，硬度和耐磨性。     

Thermodynamics of electrodeposited Ni-B-SiC composite coatings

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The properties of electrodeposited Zn-Co coatings

The possibility of increasing the corrosion resistance of automotive sheet steel by electrodepositing with Zn-Co alloy coatings was investigated. Process variables during electrodeposition such as current density, electrolyte flow rate, and pH were varied in order to examine their influence on the electroplating process. Cobalt contents varying from 0.2 to 7 wt% were easily obtained. The influence of these process parameters on the characteristics of the coating could be related to the hydroxide suppression mechanism for anomalous codeposition. The structure and the morphology of the coatings were determined using SEM and XRD analysis. Application properties important for coating systems used in the automotive industry, such as friction behavior, adhesion, and corrosion behavior, were investigated on coatings with varying cobalt content. The corrosion resistance of the Zn-Co alloy layers was found to be better than that of pure zinc coatings.     

MB8镁合金阴极电沉积Ni-SiC纳米复合镀层微观结构及性能

采用以硫酸镍为主盐的电沉积技术,在MB8形变镁合金表面制备纳米复合镀层。利用扫描电镜和透射电镜观察复合镀层的显微形貌和微观结构,利用X射线衍射仪和能谱仪对复合镀层进行物相分析,利用显微硬度计测定镀层显微硬度,利用快速磨损试验机测试复合镀层的耐磨性能,利用电化学测试仪测定复合镀层在3.5%NaCl（质量分数）溶液中的极化曲线。结果表明：在MB8形变镁合金表面可以获得结晶均匀、结构致密的纳米复合镀层,该复合镀层的显微硬度最高达HV 682,其耐磨性能超过硬铬镀层,且具有较好的耐蚀性能,自腐蚀电位较镁合金基体提高677 mV。     

Theoretical study of hardness variation with pulse parameters in composite coatings electrodeposited by pulsed currents

Theoretical aspects of the electrodeposition of composite coatings prepared by pulsed currents and also the variation of coatings hardness with the pulse parameters have been presented in this paper. The effect of the grain size, polarisation, pulse-plating parameters and incorporation of ceramic particles on the hardness or flow stress are also reported. The theoretical relationship obtained showed that with increasing polarisation and particle incorporation, the hardness of the coatings was increased. In addition, by decreasing the grain size, frequency and duty cycle the hardness was increased.     

Preparation and tribological behavior of electrodeposited Ni-W-GO composite coatings

Ni-W-GO composite coatings were successfully plated on 45# steel substrate by co-electrodeposition technique in a Ni-W electrolyte solution,with different contents of graphene oxide(GO)nanoparticles in suspension.The structure,phase composition and surface morphology of as-plated composite coatings were characterized by Raman,X-ray diffraction(XRD),scanning electron microscopy(SEM)attached with energy disperse spectroscopy(EDS),respectively.The hardness and tribological behavior of the present coatings were also evaluated by Vickers Hardness tester and high-speed reciprocating friction and wear tester,and the wear mechanism was discussed as well.The results show that layer-structured GO nanoparticles significantly affect the microstructure and grain size of the Ni-W-GO composite coatings.Meanwhile,GO nanoparticles embedded in NiW-GO coatings can obviously improve the hardness and wear resistance in comparison with the corresponding NiW coatings.The highest microhardness and wear resistance of Ni-W-GO composite coatings are obtained with 0.15 g·L~(-1)GO employing.     

电沉积参数对Co-BN（六方、）纳米复合涂层显微组织和摩擦性能的影晌

通过扫描电镜、场发射扫描电镜、能谱、原子力显微镜和X射线衍射等测试技术,研究电流密度、占空比和频率对电沉积Co—BN（六方）纳米复合涂层的显微组织和BN粒子含量的影响。同时,研究其显微硬度、摩擦性能以及磨损机理。随着电流密度和频率的增加,涂层的BN粒子含量和显微硬度先增加后减少。另外,通过减少占空比,可以沉积更多的BN粒子并且得到更高的显微硬度。在占比空10％,频率50Hz和电流密度100mA／cm2的条件下,可以得到最佳的涂层摩擦性能。     

Structure and characteristics of electrodeposited RE-Ni-W-P-B_4C-PTFE composite coatings

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The effects of pulse-reverse parameters on the properties of Ni-carbon nanotubes composite coatings

A nickel based composite coatings reinforced with carbon nanotubes (CNTs) were prepared by pulse-reverse electrodeposition. The effects of reverse ratio and frequency on the surface morphology, micro-hardness and corrosion resistance of Ni-CNTs composite coatings were studied. The results showed that higher pulse reverse ratio and pulse frequency made the surface morphology of the coatings more homogeneous. The micro-hardness of the coatings increased with the increase of reverse pulse ratio but decreased with the increase of pulse frequency. Corrosion resistance of the coatings first increases then decreases as the pulse frequency and reverse ratio increase. The best corrosion resistance was obtained for coatings under the condition of 30% reverse ratio and 100 Hz pulse frequency. The effects of CNTs on the properties of the composite coatings were discussed.     

Synthesis and properties of electrodeposited Ni-CeO_2 nano-composite coatings

Current machinery requires metallic materials to have better surface properties. Based on an orthogonal experimental design and analysis method, the CeO_2-reinforced nickel nano-composite coatings were prepared by direct current electrodeposition in a nickel sulfate bath containing CeO_2 nanoparticles. Statistical results indicate that current density is the most significant variable in the electrodeposition processing, while temperature is the least important factor. The microstructure of Ni and Ni-CeO_2 nano-composite coatings was characterized by scanning electron microscopy(SEM) equipped with energy-dispersive spectroscopy(EDS), and X-ray diffraction(XRD).The microhardness of the Ni coating is enhanced by the incorporation of CeO_2 nanoparticles. Potentiodynamic polarization and electrochemical impedance spectroscopy(EIS) were used to characterize the corrosion behavior of Ni and Ni-CeO_2 coatings. These studies show that NiCeO_2 coating has better corrosion resistance compared to Ni coating.     

电沉积Co-Cr3C2纳米复合涂层的热稳定性

研究了电沉积Co-Cr3C2纳米复合涂层的热稳定性.析出相Cr3C2颗粒均匀弥散地分布在涂层中,质量分数大约为30％.600℃以上退火导致涂层当中形成孔隙.400℃以下和600℃以上退火分别有利于Co纳米晶粒沿[002]和[220]方向生长.低于400℃退火可以同时获得优异的耐磨性和高硬度.经低于400℃退火,涂层的摩擦系数达到0.12,而经200℃退火后的涂层的摩擦系数低至0.04.