纳米Al2O3及PTFE的加入对镀层性能的影响

在化学镀Ni-P合金镀液中添加纳米Al2O3及PTFE制得Ni-P/PTFE-Al2O3复合镀层.研究了纳米Al2O3及PTFE的添加量对镀层硬度、磨损及减摩性能的影响.结果表明:纳米Al2O3及PTFE的加入能提高Ni-P合金镀层的硬度、耐磨及减摩性.     

Q235B钢表面复合防护层的制备及其有效性能

正0前言Ni-P化学镀层均匀、致密、光亮、硬度高、耐蚀耐磨性好,但其减摩性及润滑性较差。如果将聚四氟乙烯(PTFE)粒子加入Ni-P化学镀液中,形成Ni-P-PTFE复合镀层,就可以提高化学镀Ni-P层的减摩性能。然而,PTFE表面能极低,不易被润湿,而且分散性较差,故镀液的稳定性难以控制。为此,本工作先在Q235B钢表面化学镀Ni-P合金层,再制备PTFE涂层,经过风干、固化后烧结成型,得     

TC4钛合金不同表面预处理对化学镀Ni-P合金性能的影响

为了进一步弄清钛材表面不同预处理工艺对其后化学镀Ni-P合金层性能的影响,应用预浸镀镍、磷化、氟化物-磷酸盐化学转化及微弧氧化方法对TC4钛合金(Ti-6Al-4V)表面进行了预处理。采用综合测试及电化学测试技术,研究了TC4钛合金不同表面预处理对Ni-P合金化学镀层沉积速度、结合力、耐磨性及耐蚀性的影响。结果表明:TC4钛合金表面预浸镀镍和微弧氧化后,Ni-P合金化学镀层沉积速度较快,且与基体结合更好,至少能承受40 N载荷,但其表面的平整度比磷化和氟化物-磷酸盐化学转化后的差;预浸镀镍后的表面Ni-P合金镀层的耐蚀性最好,微弧氧化膜表面的Ni-P合金镀层耐磨性最好,摩擦系数减小至0.12;微弧氧化膜提高了基体表面的化学活性,同时增强了对Ni-P合金化学镀层具有类似"抛锚作用"的机械力,增强了其与基体的结合力。     

Ni-P/Ag纳米复合化学镀层的耐磨损性能

Ni-P/非金属纳米化学镀溶液中纳米粒子容易团聚,镀液难以保持稳定性.在化学镀Ni-P溶液中添加纳米银粒子,在钢铁基体上制备了Ni-P/Ag纳米复合镀层.用显微硬度计、金相显微镜等技术分析了镀层的厚度、硬度和表面形貌,用磨损试验机研究了镀层的耐磨损性能.结果表明:银纳米粒子在镀液中的含量为1.0×10-7mol/,L,银纳米粒子加快了镀层的沉积速度,使纳米复合镀层厚度增加;在相同的施镀条件下,Ni-P/Ag纳米复合镀层比Ni-P镀层具有更高的硬度和更好的耐磨损性能.     

AZ91D镁合金表面Ni-P化学镀层的微观组织与性能

以直接化学镀的方法在AZ91D镁合金表面制备了光亮、均匀、致密、厚度达40μm的Ni-P合金镀层,用现代分析技术分析了镀层的微观形貌、组织成分、显微硬度、结合力以及耐蚀性能.结果表明:Ni-P镀层属于中磷镀层,微晶结构,表面形貌呈胞状;镀层与基体结合良好;镀层的显微硬度比基体提高了4倍;镀层与抛光基体的结合力比未抛光的高,基体表面保持机加工状态的镀层破坏临界载荷为80.6 N;镀层具有较好的耐蚀性能.     

稀土铈对化学镀Ni-P-PTFE复合镀层防垢性能的影响

采用化学镀的方法在45号碳钢试样表面制备了稀土铈促进共沉积的Ni-P-PTFE复合镀层,利用扫描电子显微镜观察和分析了镀层的表面形貌,研究了稀土铈浓度对复合镀层的表面形貌、镀层的沉积速率、镀层中PTFE含量以及镀层防垢性能的影响。结果表明,适量稀土铈的加入使得镀层表面黑色粒子更加密集,即PTFE在镀层中的含量增加,在铈浓度为0.04g/L时达到最大;镀层的沉积速率与镀层中PTFE含量均随铈浓度的增加而呈现先升后降的趋势,在铈浓度为0.04g/L时分别达到最大值28.25μm/h和40.43%,而镀层中PTFE含量也随着沉积速率的增加而升高;铈的加入提高了镀层的防垢性能,镀层的结垢率随着铈对镀层中PTFE含量的影响而发生变化,当铈浓度为0.04g/L时,结垢率最低,仅为9.026g/m2,防垢效果最佳。     

脉冲电沉积Ni-P/纳米Al2O3复合镀层的性能

Ni-P/纳米Al2O3复合镀层具有良好的耐磨、耐腐蚀性能,但有关脉冲电沉积Ni-P/纳米Al2O3复合镀层的报道较少.采用脉冲电沉积方法制备了Ni-P/纳米Al2O3复合镀层,研究了复合镀层的表面形貌、结构及其在5%NaCl溶液中的耐腐蚀性能,并对300,400,500℃热处理后的复合镀层的显微硬度进行了测试.结果表明:Ni-P/纳米Al2O3复合镀层的耐蚀性优于1Cr18Ni9Ti不锈钢,但比Ni-P合金镀层差;随镀液中纳米Al2O3浓度增大,复合镀层的显微硬度提高,镀液中纳米Al2O3浓度为25.0 g/L时制得的复合镀层的硬度为685.5 HV;Ni-P/纳米Al2O3复合镀层经400℃热处理后硬度最高.     

回转体表面喷射电沉积Ni-P-ZrO2复合镀层耐腐蚀性能研究

为延长回转体零件的使用寿命,提高其耐腐蚀性能,本文利用喷射电沉积技术在45钢外圆表面制备Ni-P合金镀层和Ni-P-ZrO₂复合镀层,采用扫描电镜、腐蚀失重法和电化学测试分析等测试手段对Ni-P-ZrO₂复合镀层、Ni-P合金镀层和45钢基体在50 g/L NaCl溶液中的表面形貌和耐腐蚀性能进行研究,并探究腐蚀机理。研究表明:Ni-P-ZrO₂镀层相对Ni-P镀层表面致密度更高,缺陷较少;浸泡相同时间, Ni-P-ZrO₂镀层的失重量最小,腐蚀速率最小;电化学测试实验中,Ni-P-ZrO₂复合镀层的腐蚀电流最低(43.2×10^-5 A/cm²),共沉积ZrO₂颗粒后,Ni-P-ZrO₂复合镀层容抗弧半径更大,极化电阻值R_p增大为Ni-P合金的3倍,双层电容值C_d由4.743 8 μF/cm²降低为3.887 2 μF/cm²。在相同条件下腐蚀后,Ni-P-ZrO₂复合镀层的表面较为完好,腐蚀产物较少;Ni-P合金次之,有较多黑色腐蚀产物;45钢表面形貌最差。综上,采用喷射电沉积在回转体表面制备的Ni-P-ZrO₂复合镀层相对Ni-P合金镀层和45钢基体表现出更优良的耐腐蚀性能。     

锅炉炉管Ni—P—PTFE化学复合镀层研究

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。     

Ni-P多元合金及复合化学镀层的研究进展

综述了化学镀Ni-W(Cu,Ce)-P等三元及四元合金镀层和Ni-P-SiC(Al2 O3)耐磨复合镀层及Ni-P-(MoS2,PTFE)自润滑复合镀层的制备工艺,论述了W、Cu等合金元素及SiC、MoS2增强体引入对Ni-P镀层微观结构与性能的影响,指出特种合金化及多形态增强体复合将成为Ni-P化学镀研究的发展趋势.     

钛合金表面电泳沉积法制备YSZ/HAp纳米复合涂层

采用电泳沉积法在钛合金基体上制备了YSZ/HAp纳米复合涂层,用场发射扫描电镜、X射线衍射和能量散射谱对复合涂层HAp外层的表面形貌和晶相、复合涂层的断面形貌及元素组成分布进行分析研究,通过粘结-拉伸实验测定了涂层与基体的结合强度.结果表明YSZ/HAp纳米复合涂层与钛合金基体的结合强度明显高于HAp单一涂层与钛合金基体的结合强度,说明YSZ/HAp的复合缓和了HAp涂层与钛合金基体之间的热膨胀系数失配现象,改善了涂层与基体之间的结合.     

Ti6Al4V合金激光原位合成自润滑复合涂层高温摩擦学性能

为提高Ti6Al4V合金的高温摩擦学性能,采用激光熔覆技术在其表面原位合成多相混杂金属基高温自润滑耐磨复合涂层,熔覆粉末的成分为Ni60-16.8%TiC-23.2%WS_2(质量分数,下同),系统地研究复合涂层的显微组织、物相结构及其在20,300,600,800℃下的摩擦学性能和相关磨损机理。结果表明:复合涂层的显微硬度(701.88HV_0.5)约为基体(350 HV_0.5)的2倍;由于原位合成固体润滑相(Ti_2SC/TiS/NiS/TiO/TiO_2/NiCr_2O_4/Cr_2O_3)和硬质相(W,Ti)C_1-x/TiC/Cr_7C_3的协同作用,复合涂层的耐磨减摩性能明显优于基体。随着温度升高,涂层和基体的摩擦因数和磨损率均呈下降趋势,在800℃时复合涂层和基体的摩擦因数分别为0.32和0.43,磨损率分别为1.80×10^-4,2.92×10^-5mm/Nm。在800℃下塑性变形、分层和氧化磨损为基体主要磨损机理,复合涂层以氧化磨损和轻微的黏着磨损为主。     

激光熔敷Ti5Si3/NiTi2复合材料涂层的组织与耐磨性

以Ti-Si-Ni合金粉末为原料，利用激光熔敷技术在BT9钛合金表面制备出了以金属间化合物Ti5Si3为增强相，以NiTi2为基体的Ti5Si3/NiTi2金属间化合物快速凝固耐磨复合材料涂层，Ti5Si3/NiTi2合材料涂层的硬度高，组织均匀，致密，与基材之间为完全冶金结合，在干滑动磨损试验条件下具有很好的耐磨性。     

Laser surface coating of Mo–WC metal matrix composite on Ti6Al4V alloy

Laser surface alloying of Mo, WC and Mo–WC powders on the surface of Ti6Al4V alloys using a 2 kW Nd-YAG laser was performed. The dilution effect upon the microstructure, microhardness and wear resistance of the surface metal matrix composite (MMC) coating was investigated. With a constant thickness of pre-placed powder, the dilution levels of the alloyed layers were found to increase with the incident laser power. The fabricated surface MMC layer was metallurgically bonded to the Ti6Al4V substrate. The microhardness of the fabricated surface layer was found to be inversely proportional to the dilution level. The EDAX and XRD spectra results show that new intermetallic compounds and alloy phases were formed in the MMC layer. With the existence of Mo content in the pre-placed powder, the β-phase of Ti in the MMC coating can be retained at the quenching process. With increasing weight percentage content of WC particles in the Mo–WC pre-pasted powder, the microhardness and sliding wear resistance of the laser surface coating were increased by 87% and 150 times, respectively, as compared with the Ti6Al4V alloy. The surface friction of the laser-fabricated MMC coatings was also decreased as compared with the worn Ti6Al4V substrate.     

Effect of titanium and titania on chemical characteristics of hydroxyapatite plasma-sprayed into water

HA and its composite particles (HA/Ti, HA/TiO₂) were plasma-sprayed into water as well as on the Ti substrate, respectively. The microstructure and phase compositions of the sprayed HA and its composite particles before and after impinging on the substrate were studied by using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. The results showed that the HA in the composite particles sprayed into water had a higher crystallinity than that in the composite coating. The addition of Ti or TiO₂ could both influence the decomposition of HA, but no chemical reacting product between them was formed before and after impinging on the substrate. However, EDS analyses showed the occurrence of interdiffusion of elements between HA and TiO₂, which was favorable to enhance the cohesive strength of particles in the composite coating. The post heat treatment at 650 °C for 2 h can effectively improve the crystallinity of coating by transforming amorphous phases into HA.     

激光熔覆制备原位自生TiC增强Ni3（Si,Ti）复合涂层研究

运用激光熔覆技术修复受损的烟汽轮机叶片,在GH864镍基合金表面制备原位自生TiC颗粒增强Ni3(Si,Ti)金属间化合物复合涂层.利用扫描电镜、能谱分析仪、X射线衍射仪及显微硬度计研究了(Ti+C)的加入量对熔覆层组织及硬度的影响.研究表明:在优化的工艺参数下可获得宏观质量完好,无裂纹、气孔等缺陷,且与基体呈冶金结合的激光熔覆层,熔覆层由Ni(Si)、Ni3(Si,Ti)和TiC组成;当合金粉末中(Ti+C)的加入量为20%时熔覆层的硬度最高可达780Hv,是基体材料的2.4倍.     

低温熔盐电沉积羟基磷灰石复合涂层的研究

为了提高羟基磷灰石涂层的结合强度,在AlCl3-NaCl-TiCl3低温熔盐体系中加入HA微粒,复合电沉积制备Al-Ti/HA复合涂层,并对涂层的表面形貌、结构和结合强度进行了研究.结果表明: HA微粒均匀分散在Al-Ti合金镀层中,其共沉积量随电流密度的减小和熔盐中HA浓度的增大而增强;涂层的结合强度随HA共沉积量的增大而增强,当HA的共沉积量为40.1%(质量分数)时,Al-Ti/HA复合涂层的结合强度达到28.1 MPa.     

Effect of Substrate Type on Deposition Behavior and Wear Performance of Ni-Coated Graphite/Al Composite Coatings Deposited by Cold Spraying

This work focused on the deposition characteristics and wear behavior of Ni-coated graphite mixed with40 vol.% Al(Ni-Gr/Al) composite coatings sprayed on an Al alloy and a steel substrate by cold spraying(CS). The morphology of the ?attened Ni-Gr particles was examined by single-impact tests. Crosssectional microstructure and wear performance of the Ni-Gr/Al composite coatings were studied. Results showed that a larger number of Ni-Gr particles were ?nally bonded with the steel substrate, whereas many craters existed on the Al alloy substrate after the single-impact tests. The coating on the steel substrate had a high thickness, high graphite content and low coe?cient of friction(COF) compared to those on the Al alloy substrate. In addition, the CS coatings presented a homogeneous distribution and uniform morphology of graphite, and a comparative COF to that of conventional thermal sprayed coatings. It was shown that CS could avoid the decomposition and transformation of graphite phase.     

In situ composite coating of titania-hydroxyapatite on titanium substrate by micro-arc oxidation coupled with electrophoretic deposition processing

In situ composite coating of hydroxyapatite (HA)/TiO₂ were produced on titanium (Ti) substrate by micro-arc oxidation coupled with electrophoretic deposition (MAO&EPD) technique with different concentrations of HA particles in the 0.2 M NaOH electrolyte solution. The surface morphology and chemical composition of the hybrid coating were effected by HA concentration. The amount of HA particles incorporated into coating layer increased with increasing HA concentration used in the electrolyte solution. The corrosion behavior of the coating layer in simulated body fluids (SBF) was evaluated using a potentiodynamic polarization test. The corrosion resistance of the coated sample was increased compared to the untreated Ti sample. The in vitro bioactivity assessment showed that the MAO&EPD treated Ti substrate possessed higher apatite-forming ability than the untreated Ti. Moreover, the apatite-forming ability had a positive correlation with HA concentration. In addition, the cell behavior was also examined using cell proliferation assay and alkaline phosphatase ability. The coating formed at HA concentration of 5 g/L exhibited the highest cell ability.