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钻具接头失效大多发生在螺纹表面,对螺纹表面镀铜、磷化处理能有效缓解螺纹粘扣,但镀铜、磷化工艺污染严重,为此,在钻具接头螺纹表面制备镍钨合金镀层,研究了表面镀镍钨合金对钻具螺纹性能的影响.试验表明:镍钨合金镀层显微硬度在700~900 HV1N,为基体材料硬度的2~3倍.镍钨合金镀层厚度在螺纹的牙顶面、牙侧面和牙底面依次降低,呈不均匀分布,对螺纹牙工作时的啮合度有不利的影响;镍钨合金镀层接头在前3次上卸扣试验中发生表面损伤.疲劳寿命试验结果发现镍钨合金镀层试样的疲劳寿命为对照组试样的20%左右.分析认为镍钨合金镀层的非晶结构明显提高了镀层硬度,但塑性变形能力差,降低了材料的疲劳性能,镀层厚度的不均匀导致接头严重粘扣. 相似文献
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目前,对镁合金表面镍钨合金镀层的研究多为化学镀镍钨磷三元镀层,工艺复杂,能耗高.采用电沉积法在AZ91D镁合金制备镍钨镀层,采用场发射扫描电镜(FESEM)、能谱成分分析(EDS)和X射线衍射(XRD)对镀层的表面形貌和成分进行分析,用维氏硬度计测量镀层硬度,测量AZ91D镁合金及镀层在3.5 %NaCl溶液中极化曲线,并结合盐雾试验判定其耐腐蚀性,研究了镀液中钨酸钠含量对所得镀层性能的影响.结果表明:随着镀液中Na2WO4·2H2O浓度的增加,镀层钨含量不断增加,镍钨置换固溶体数量增加,从而起到提高镀层硬度和耐磨性、细化镀层晶粒、提高耐蚀性的效果;Na2 WO4·2H2O浓度超过65 g/L时,继续添加Na2WO4·2H2O对镀层优化作用减弱;当Na2WO4·2H2O浓度为75 g/L时,镀层钨含量为25.06%,硬度达483 HV,自腐蚀电位-1.124 V,自腐蚀电流10.80 μA/cm2,所制备的镍钨镀层对镁合金基体具有耐磨耐蚀保护作用. 相似文献
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研究了化学镀Ni-Cu-P非晶态合金镀层的成分,结构、硬度及形貌等性能.研究结果表明:镀层中铜含量随着镀液中硫酸铜浓度的增加而提高,镍、磷含量随着镀液中硫酸铜浓度的增加而降低。由于铜具有优先析出的特征,导致合金镀层中Cu/Ni质量比远高于镀液中Cu^2+/Ni^2+质量比.在镀态下,Ni-Cu-P合金镀层为含铜、磷原子的镍基饱合固溶体.X-ray衍射表明:在镀态下及300℃以下热处理时,Ni-7.929%Cu-8.227%P(质量分数)合金镀层为非晶态结构,经400℃热处理后,开始有热力学平衡相Ni3P和Cu3P析出,合金镀层已转为晶态结构.Ni-7.929%Cu-8.227%P合金镀层的硬度随热处理温度的升高而增加,在400℃时,硬度达到最大值(845HV),热处理温度继续升高,合金镀层的硬度反而下降. 相似文献
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为了探讨1,4-丁炔二醇对纳米晶镍镀层硬度和耐蚀性的影响,采用直流电沉积法在黄铜表面制备了纳米晶镍镀层。利用X7000 X射线衍射仪、FEI Quanta600 FE-SEM扫描电镜、DUH-211S动态超显微微米压痕仪、动电位极化曲线及阻抗谱,研究了不同浓度1,4-丁炔二醇对镍镀层结构、硬度及耐蚀性的影响规律。结果表明:随着镀液中1,4-丁炔二醇浓度的增加,镍镀层晶面的择优取向由(200)织构向(111)转变,晶粒尺寸减小;镍镀层硬度增加,在1,4丁炔二醇浓度为0.5 g/L时达到654 HV;在3.5%Na Cl(质量分数)溶液中当1,4-丁炔二醇浓度为0.1 g/L时,镍镀层的耐腐蚀性最好。 相似文献
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非晶态Ni-W合金镀层的高温氧化性能研究EI 总被引:2,自引:0,他引:2
研究了Ni-W合金镀层的抗高温氧化及镀层加热处理后的硬度。为了进一步提高非晶态合金(Ni-W)镀层的性能,往镀液中又加入了P、Mo、Ce、B元素。 相似文献
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采用电沉积工艺制备了Fe-P非晶镀层,并研究了Fe-P非晶镀层在加热过程中镀层结构与硬度的变化趋势,结果表明:该镀层在300℃左右开始晶化,在330℃左右Fe-P合金开始转变为α-Fe(P)固溶体,到370℃左右铁磷化合物FexP(X=1,2,3)从α-Fe(P)固溶体中脱溶析出,由于固溶强化和弥散强化的作用导致镀层硬度增大,并在370℃达到最大值,当热处理温度继续增高至460℃后,镀层中弥散相粒子逐渐长大,即发生Ostwald熟化现象,从而导致镀层硬度快速下降。 相似文献
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目前有关纳米复合镀层电沉积的研究还不够深入、系统。以瓦特镀镍液为基础,在Q235A钢基体上制备镍-纳米金刚石复合镀层,研究了纳米金刚石浓度、搅拌速度对镍-纳米金刚石复合镀层性能的影响规律。在测试纳米金刚石复合镀液中镍的还原行为时发现,随着纳米金刚石浓度的升高,镍离子的极化程度呈现先升高后下降的趋势,镀液中纳米金刚石浓度为8.0 g/L时极化程度最大,同等条件下直流电沉积制备的复合镀层硬度、弹性模量分别为4.66 GPa和195.2 GPa,而双脉冲电沉积制备的镀层硬度和弹性模量分别达到5.23 GPa和197.4 GPa。 相似文献
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Electrodeposition and mechanical and corrosion resistance properties of Ni-W/SiC nanocomposite coatings 总被引:1,自引:0,他引:1
Ni-W/SiC nanocomposite coatings with various contents of SiC nano-particulates were prepared by electrodeposition in Ni-W plating bath containing SiC particulates. The influences of the SiC nano-particulates concentration, current density and stirring rate of the plating bath on the composition of the nanocomposite coatings were investigated. The surface morphologies of the Ni-W alloy and Ni-W/SiC nanocomposite coating were observed using a scanning electron microscope (SEM). The morphology of Ni-W/SiC nanocomposite coating is smoother than that of Ni-W alloy coating. The microhardness of composite coatings increases with the increasing content of the SiC nano-particulates in the coatings. The corrosion behavior of Ni-W alloy and Ni-W/SiC nanocomposite coatings was evaluated by the anodic polarization curves in 0.5 mol/L NaCl solution at room temperature. It shows that Ni-W/SiC nanocomposite coating has better corrosion resistance than the Ni-W alloy coating. 相似文献
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研究了在氢气气氛中,不同的热处理温度对Ni-W合金镀层表面状态、相结构及显微硬度和耐蚀性的影响。结果表明,镀态的Ni-W合金镀层存在一种未知相(2θ≈41.4°),热处理过程中这一未知相消失,同时镀层中析出NiW、Ni_4W等沉淀相。随着热处理温度的升高,镀层的晶粒度逐渐增大,镀层在热处理过程中形成的孔隙逐渐增多。当热处理温度达到1 000℃后,镀层表面出现明显的裂纹,同时镀层中可还原形成单质W。Ni-W合金镀层的显微硬度经热处理后显著增大,热处理温度为500℃时镀层的显微硬度最大,同时镀层具有与镀态Ni-W合金相近的耐蚀性,热处理温度进一步升高后镀层的耐蚀性降低。 相似文献
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The heat treatment effect on the structure and mechanical properties of electrodeposited nano grain size Ni-W alloy coatings 总被引:1,自引:0,他引:1
The Ni-W alloy coatings with tungsten content from 32.5 to 61.2 wt.% were prepared in this study by electro-deposition. Experimental results show that the grain size of Ni-W coatings evaluated by XRD decreased with increasing tungsten content in coatings, however, the micro-hardness increased with increasing tungsten content. As-deposited Ni-61.2 wt.%W coating has amorphous-like structure and the grain size is around 1.5 nm, after annealing at 500 °C, the hardness of the coating is promoted to 1293 Hv owing to formation of Ni4W and NW precipitates. In addition, the heat-treated Ni-W coatings show a better wear resistance than the as-plated Ni-W coatings. 相似文献
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C.H. Zac A.R. Bushroa M. Sarraf M. Rizwan M.F. Jamaludin 《Materialwissenschaft und Werkstofftechnik》2021,52(9):952-964
Ti-6Al-4V alloy is a bioinert material with low bioactive properties, which may hamper its bonding ability with body tissues that can be overcome by coating the metal with a bioactive glass layer, 45S5 reinforced zirconia. This coating can be deposited using an electrophoretic deposition process. In this study, a comparison is made between three types of coatings which are bioglass, pure zirconia and bioglass reinforced zirconia before and after heat treated. Mechanical evaluations using scratch tests and micro-hardness tests are conducted to evaluate the adhesion strengths and hardness properties of the coatings. The results show the presence of oxygen, and variations in the amounts of bioglass and zirconia, due to the activity of crystallization. X-ray diffraction confirms presence of all precursor elements in the coatings. The highest hardness value of 414 HV 2.942 is obtained for the sintered bioglass-zirconia composite coating, as compared to the hardness of bare titanium alloy of 266 HV 2.942. The highest adhesion strength of 1929 mN is also obtained for the bioglass-zirconia composite coating. These results show excellent performance for sintered bioglass-zirconia composite coating, making it a potential coating material for biomedical implants. 相似文献
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Nanoparticle reinforced nickel matrix composite coatings, such as n-Al2O3/Ni, n-SiO2/Ni, n-SiC/Ni and n-TiO2/Ni, were fabricated by brush plating technique. Hardness, wear resistance and contact-fatigue resistance of the composite coatings were determined, and strengthening mechanism of the composite coatings was discussed. Results showed that the composite coatings had superior properties to the Ni metal coating. Compared with properties of brush plated Ni metal coating, the composite coatings had hardness over 1.5 times and wear resistance capability of about 2.5 times. The strengthening mechanism of the composite coatings mainly included fine-crystal grain effect, nanoparticle dispersion effect and dislocation effect. 相似文献
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n-Al2O3/Ni复合电刷镀层的接触疲劳行为 总被引:2,自引:0,他引:2
为研究纳米颗粒复合电刷镀层的接触疲劳行为,通过在镍盐溶液中加入纳米氧化铝(n-Al2O3)颗粒,采用电刷镀技术制备了含n-Al2O3颗粒的镍基复合镀层(n-Al2O3/Ni),采用接触疲劳试验机评价了镀态和热处理态的n-Al2O3/Ni复合镀层的抗接触疲劳性能,并与纯镍刷镀层进行了性能对比.借助SEM和TEM对复合刷镀层的组织进行了分析,探讨了复合刷镀层的接触疲劳失效过程以及纳米颗粒等对刷镀层疲劳失效过程的影响.研究表明:n-Al2O3/Ni复合镀层在镀态下的接触疲劳寿命超过100万周次,明显高于纯镍镀层;退火后n-Al2O3/Ni复合镀层接触疲劳寿命为45.9万次,为纯镍镀层的1.62倍;复合镀层的接触疲劳失效过程分为裂纹萌生、裂纹扩展和镀层断裂3个阶段;纳米颗粒在复合镀层接触疲劳失效过程中起到阻碍位错滑移的作用,从而抑制塑性变形和裂纹扩展,使复合镀层具有较高的接触疲劳寿命. 相似文献