含纳米粉镀液的电刷镀复合镀层试验研究

应用电刷镀技术制备了含有纳米SiC粉的镍基复合镀层，对该复合镀层的显微硬度和摩擦学性能进行了测试，并讨论了主要工艺参数对这些性能的影响规律。测试结果表明：纳米SiC粉的加入可以一定程度的提高复合镀层的硬度。快镍复合纳米SiC镀层的摩擦因数低于快镍镀层的摩擦因数。镀液中纳米SiC粉和添加剂浓度增加时，复合镀层的摩擦因数有降低趋势。与快镍镀层相比，快镍复合纳米SiC镀层的耐磨性有较大幅度的提高。还采用光学显微分析(OM)和电子探针(EPMA)研究了对该复合镀层的表面形貌、组织和元素分布特点，并提出了纳米SiC粉与镍共沉积的机理。     

脉冲电沉积纳米晶Zn涂层的结构表征与摩擦学性能

采用脉冲电沉积法,通过调节电流密度控制涂层的晶粒尺寸,在铜基体上制备了平均晶粒尺寸为6~32 nm的Zn涂层,采用XRD, SEM和显微硬度、摩擦实验等手段,表征了涂层的微观结构,并研究了其力学性能与摩擦学性能. 结果表明,纳米晶Zn涂层的表面平整致密,平均晶粒尺寸随电流密度增大而减小,随着晶粒尺寸减小,涂层的显微硬度增大,摩擦系数降低. 当电流密度从0.3 A/cm2增大至2.4 A/cm2时,平均晶粒尺寸从32 nm下降为6 nm,显微硬度从低于0.5 GPa增大至2.0 GPa以上,在大气环境中与Si3N4球之间的滑动摩擦系数从0.18降低至0.05. 硬度随晶粒尺寸的变化规律符合经典的Hall-Petch关系.     

镀液中石墨烯添加量对镍-石墨烯复合电镀层微观结构和耐磨性的影响

为提高巴氏合金的耐磨性,将石墨烯作为增强相添加到由240g/L NiSO_4·6H_2O、45 g/L NiCl_2·6H_2O、30 g/L H_3BO_3、20 g/L Na_2SO_4和0.1 g/L十二烷基苯磺酸钠组成的镀镍液中,在ZSnSb8Cu4合金上电沉积得到镍-石墨烯复合镀层。采用扫描电镜、X射线衍射仪和摩擦磨损试验仪考察了镍-石墨烯复合镀层的表面形貌、组织结构和耐磨性。结果表明,复合电沉积镍-石墨烯能够有效提高巴氏合金基体的耐磨性,而镀液中石墨烯添加量的增大能使镀层晶粒细化,显微硬度升高,摩擦因数和磨损率减小。当镀液中石墨烯的质量浓度为400 mg/L时,镍-石墨烯复合镀层的显微硬度较高,耐磨性最优。     

脉冲宽度对电刷镀制备Ni/CNT纳米晶复合镀层显微结构及性能的影响

在不同工艺参数下利用电刷镀技术制备镍-碳纳米管纳米镀层。将碳纳米管添加到刷镀镍的基础镀液中,并以球磨的方式加以分散。镀液中碳纳米管质量浓度为3 g/L。利用扫描电子显微镜和X-射线衍射对镀层晶粒尺寸、显微结构以及形貌进行分析,利用显微硬度仪和球磨磨损试验机对镀层硬度及磨损量进行测试。结果表明,在直流电流下所制备的Ni/CNT镀层的晶粒尺寸约为20 nm;在脉冲电流下,Ni/CNT镀层晶粒尺寸有所降低,并且当脉冲宽度变短时,镀层表面更为平整。随着热处理温度的升高,Ni/CNT镀层的晶粒尺寸有所增加,当加热温度达到500℃时,镀层晶粒尺寸超过50 nm。脉冲电流下所制备的镀层的显微硬度明显高于直流电流下,并且随着脉冲的变短镀层硬度增大。在300℃以下时,Ni/CNT镀层硬度有轻微变化,当温度升高到400℃以上时,镀层硬度明显降低。脉冲电流下所制备复合镀层的耐磨性较直流电流下更好,并且随着脉冲的变短,镀层耐磨性增强。     

电刷镀镍–钨–二硫化钼复合镀层的组织和耐摩擦磨损性能

采用复合电刷镀工艺在2Cr13不锈钢基材上制备了Ni–W–纳米MoS_2复合镀层。采用扫描电镜、显微硬度计和摩擦磨损试验机对镀层微观形貌、显微硬度和耐摩擦磨损性能进行分析。结果表明:与Ni–W合金镀层相比,Ni–W–纳米MoS_2复合镀层的表面更加平整、致密,显微硬度较低,耐摩擦磨损性能较优。随镀液中Mo S2纳米颗粒质量浓度的增大,复合镀层的摩擦因数小幅下降,磨损量先降后升。当镀液含20 g/L MoS_2时,所得Ni–W–纳米MoS_2复合镀层的综合性能最优。     

电沉积法制备纳米晶Ni-Co合金镀层

在氨基磺酸盐镀液体系中,采用电沉积法制备了纳米晶镍镀层和四种纳米晶Ni-Co合金镀层,采用FESEM、EDS和XRD表征了镀层的表面形貌、成分和晶体结构。结果表明,镍镀层和四种Ni-Co镀层的晶体结构都是简单面心立方结构;与镍镀层相比,Ni-Co合金镀层的平均晶粒尺寸减小,且当镀层钴含量为41.3%时,Ni-Co合金的平均晶粒尺寸最小为14.6 nm。在一定范围内,钴含量的增加有利于改善Ni-Co合金镀层的表面质量以及实现晶粒细化。     

镍-纳米石墨复合镀层的制备及其性能表征

利用电沉积方法,在铜基表面制备了镍-纳米石墨复合镀层。讨论了镀液中纳米石墨的质量浓度对复合镀层性能的影响规律,同时分析了超声波的施加对提高复合镀层质量的作用。结果表明:当镀液中纳米石墨的质量浓度为3g/L时,所得镍-纳米石墨复合镀层的表面粗糙度为0.972 2μm,摩擦因数为0.255 8,呈现出良好的减摩性能。     

镀液成分对纳米镍-钴合金镀层显微硬度的影响

研究了镀液成分(糖精和钴)对脉冲电沉积纳米镍-钴合金镀层显微结构和显微硬度的影响.结果发现:镀液中糖精和钴的加入都可以细化晶粒,提高硬度;同时其质量浓度的进一步增加又都可以使镀层硬度下降.通过镀液中钴的加入,有机晶粒细化剂(糖精)的用量可以明显减小,这将有助于镀层性能的提高.由于糖精的过量使用会使镀层中硫和碳的杂质量增加,而这些杂质往往存在于晶界上,使镀层韧性下降.     

电沉积镍纳米晶材料制备及性能

采用直流电沉积法向镀液中加入复合有机添加荆制备了镍纳米晶材料。采用扫描电镜及X射线衍射仪分析了该纳米晶材料的微观形貌及相结构．测定了其结合强度、显微硬度及耐磨性能。结果表明,该纳米镍镀层表面致密、平整,且结合强度、显微硬度及耐磨性能优良,与粗晶镍镀层相比有较大的提高．     

温度和电流密度对亚硫酸盐电镀金的影响

采用亚硫酸盐体系镀液在紫铜表面电镀金.研究了镀液温度和电流密度对电镀金层晶相结构和纳米硬度的影响.结果表明,随着镀液温度升高,金层由(220)面择优生长转变为(111)面择优生长,纳米硬度变化不大.随着电流密度增大,金层由(111)面择优生长转变为(220)面择优生长,纳米硬度减小.电镀金层的晶粒尺寸受镀液温度和电流密...     

粘结剂对超音速火焰喷涂碳化钨涂层磨粒磨损性能的影响

采用超音速火焰喷涂(HVOF)工艺在35钢基体上制备了WC-10Ni涂层和WC-12Co涂层,研究了镍、钴这两种粘结剂对WC涂层的显微硬度、摩擦系数和抗磨粒磨损性能的影响,采用扫描电子显微镜观察涂层磨损前后的表面形貌,探讨了WC涂层的磨粒磨损机理。结果表明,以HVOF方法制备的2种WC涂层均有较高的显微硬度,WC-10Ni涂层和WC-12Co涂层与SiC砂纸摩擦副之间的干摩擦系数相差不大。2种涂层在低载荷下均有较好的抗磨粒磨损性能,但在较高载荷下WC-12Co涂层的抗磨性明显优于WC-10Ni涂层。2种涂层的磨粒磨损形式主要为均匀磨耗磨损,磨损机理以微切削和微剥落为主。WC-12Co涂层的磨损表面损伤较轻微,综合性能优于WC-10Ni涂层。     

Microstructure,adhesion, and tribological properties of conventional plasma-sprayed coatings on steel substrate

A variety of metallic and oxide coatings were deposited under various conditions on 1020 mild steel substrate by conventional plasma spraying. The coating thickness, microhardness, cohesion and adhesion failure loads, friction coefficient, and abrasive wear resistance were evaluated. The coatings were classified as follows, in order of decreasing microhardness and wear resistance: alumina, chromia, 316 stainless steel, Ni-5% Al, elemental aluminum and aluminum-polyester. Wear resistance increased with increasing microhardness and decreasing friction coefficient. The microhardness and wear resistance of high-velocity oxy-fuel (HVOF) diamond jet (DJ)-sprayed aluminum were found to be superior to those of plasma-sprayed aluminum. Plasma or flame-sprayed metallic coatings adhered well to the substrate. The cohesion, adhesion, microhardness, and wear resistance of alumina coatings exceeded those of equally thick chromia coatings.     

SiC强化镍基纳米复合电刷镀层的干摩擦磨损特性

采用电刷镀技术制备了快速镍和,n-SiC/Ni、n-SiC/Ni-W复合镀层,研究了镀层的干摩擦磨损特性,测定了镀层的显微硬度,采用扫描电子显微镜(SEM)观察分析了镀层磨痕形貌.结果表明:纳米粒子的加入可以显著地提高镀层的耐磨性.纳米复合镀层的磨损机制以磨粒磨损为主,而纯镍镀层以粘着磨损和磨粒磨损为主.     

Effect of BEO in the electrodeposition process of Ni/diamond composite coatings for preparation of ultra-thin dicing blades: Experiments and theoretical calculations

Ni/diamond dicing blades is the main tool for scribe of silicon wafer at present. In order to decrease the width of dicing slot on the wafer, it is necessary to reduce the thickness of blades, and to increase the hardness, toughness and wear resistance of the Ni/diamond composite coatings in the process of electrodeposition. In this paper, 1,4-bis(2-hydroxyethoxy)-2-butyne (BEO) was used as an organic additive in the composite baths containing nickel amino-sulfonate, nickel chloride, boric acid, sodium dodecyl sulfate (SDS) and diamond particles in sizes of 3–5?µm, in order to improve the properties of Ni/diamond coatings and produce ultra-thin Ni/diamond dicing blades. The textures of Ni/diamond composite coatings were mainly Ni (200) and Diamond (111) since the addition of BEO in the baths inhibited the growth of Ni (111) and Ni (220). Quantum chemical calculations and molecular dynamics (MD) simulations showed that BEO could adsorb at the nickel surface strongly and inhibit the electrodeposition of nickel atoms. With the increase in concentration of BEO in the baths, the cathodic polarization potentials shifted to more negative direction and the thicknesses of the coatings decreased. Adding the appropriate amount of BEO (0.1–0.2?g/L) in the baths, the roughness of the coating decreased the number of individual diamond particles in the coating increased, and the hardness and the wear resistance of the coating was improved. When the thickness of Ni/diamond composite coating on aluminum alloy wheeled substrate was 15?µm, the width of its dicing slot was 22?µm. However, the addition of BEO in the bath cannot change the adhesive wear mechanism of the coating.     

Grain-Size Dependence of Sliding Wear in Tetragonal Zirconia Polycrystals

Using a pin-on-plate tribometer with the reciprocating motion of SiC against yttria-doped tetragonal zirconia polycrystal (Y-TZP) plates, the friction and wear of Y-TZP ceramics were investigated as a function of grain size in dry N₂ at room temperature. The results showed that the overall wear resistance increased as the grain size of Y-TZP ceramics decreased. For grain sizes ≤0.7 μm, the wear results revealed a Hall-Petch type of relationship ( d ^−1/2) between wear resistance and grain size. In this case, the main wear mechanisms were plastic deformation and microcracking. For grain sizes ≥0.9 μm, the wear resistance was proportional to the reciprocal of the grain diameter. In this regime, delamination and accompanying grain pullout were the main mechanisms. In this case, the phase transformation to monoclinic zirconia had a negative effect on the wear resistance of TZP ceramics. The coefficient of friction tended to be higher for fine-grained TZP-SiC couples than for coarse-grained TZP-SiC couples, whereas, for a specific regime of grain size, the coefficient of friction was almost independent of the grain size.     

A study on the electrocodeposition processes and properties of Ni�CSiC nanocomposite coatings

Ni–SiC nanocomposite coatings were prepared on a brass substrate by electrocodeposition. The electrodeposition was carried out by adding the SiC nanoparticles to a nickel-containing bath. Nickel deposition processes were analyzed by cathodic polarization curves, and the plating parameters were determined preliminarily by analyzing the effects of different technological parameters on the deposition process. Then, electrocodeposition processes were carried out with different concentrations of SiC nanoparticles in the bath. The effects of current density, stirring rate, and SiC nanoparticle’s concentration in the plating bath on the hardness of coatings were investigated by microhardness tests. Besides the microhardness tests, wearing tests and corrosion tests were also applied to the coatings with the highest hardness and coatings of pure nickel. The structures and surface morphologies of the coatings were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods. The experimental results show that the microhardness of the codeposited coating increases with increasing current density and attains a maximum at the SiC concentration of 6 g/L. The decrease in the microhardness at higher SiC concentrations may be due to agglomeration of nanosized particles in the plating bath. Increasing the stirring speed did not give a better quality deposition as coatings produced at low stirring rates always had higher microhardness values than did those at high stirring rates. Furthermore, the Ni–SiC nanocomposite coatings have lower friction coefficient and better corrosion resistance than those of pure nickel coatings.     

Tribological properties of YSZ and YSZ/Ni-YSZ nanocomposite coatings prepared by electron beam physical vapour deposition

Metal-ceramic nanocomposite coatings have been applied to many industrial applications owing to their remarkable properties such as wear, corrosion and high temperature oxidation resistance than that of metals and alloys in high temperature environments. In this study, YSZ and Ni-YSZ nanocomposite coatings deposited by electron beam physical vapour deposition (EBPVD) for high temperature environments have been investigated. Initially friction and wear behaviour of YSZ coatings deposited at various substrate temperature were studied. Then the effect on wear response of Ni-YSZ nanocomposites with different Ni content were investigated using a ball-on-disc micro tribometer. The structural and tribochemical changes that occurred in the wear tracks of YSZ and Ni-YSZ coatings were investigated using field emission scanning electron microscopy and Raman spectroscopy. The results obtained on sliding wear and friction behaviour of these nanocomposite coatings suggest that 50 wt.% of Ni in YSZ nanocomposite provides good wear resistance behaviour than that of other coatings. Such an improvement in tribomechanical and wear performance of the nanocomposite coating could be attributed to the optimum amount of Ni which promotes the formation of NiO from Ni due to the frictional heat between nanocomposite coating and the sliding counter body in wear track as confirmed by Raman analysis.     

Investigation of high temperature wear resistance of TiCrAlCN/TiAlN multilayer coatings over M2 steel

In this study, TiCrAlCN/TiAlN multilayer coatings were deposited on M2 high speed steel substrates by the Closed-Field Unbalanced Magnetron Sputtering system. The chemical composition, microstructure, morphology, mechanical and high temperature wear resistance properties of the coatings were characterized, analyzed and compared to the substrate. The high temperature wear tests were carried out under a load of 2 N at the lap (wear test distance) of 50 m and in dry sliding condition at Room Temperature (RT), 150, 300, 450, and 600 °C on atmospheric conditions. It has been found that the TiCrAlCN/TiAlN multilayer coatings have a higher wear resistance than the M2 substrate. The stable friction behavior and low friction tendency was determined at 600 °C. When the test temperature increased, the wear rates decreased. Narrow and smooth wear tracks and also the lowest wear rate were obtained at 600 °C.     

Preparation and tribocorrosion performance of CrCN coatings in artificial seawater on different substrates with different bias voltages

The CrCN coatings have been prepared by multi-arc ion plating technology with different bias voltages on 316?L, TC4 and H65 substrates, respectively. The prepared CrCN coatings have been characterized by XRD, SEM, and EDS, respectively. The mechanical properties, electrochemical corrosion behavior, and tribological performance of prepared coatings were tested by microhardness tester, scratch tester, electrochemical workstation, and friction and wear tester, respectively. Results show that the CrCN coatings with bias voltage of ?50?V presented the finer grain size, denser structure, better comprehensive mechanical properties and friction, and better corrosion resistance than the CrCN coatings with a bias voltage of ?30?V. The coating on TC4 substrate show the lower hardness, the better adhesion, the better electrochemical properties and tribological properties than that on 316?L substrate. The coatings based on H65 Cu substrate presented the worst electrochemical and wear properties. The CrCN coating with a bias voltage of ?50?V on TC4 substrate is an optimal candidate in artificial seawater for tribocorrosion.     

铝锂合金表面化学镀镍工艺及膜层耐腐蚀性能研究

为解决铝锂合金强烈电腐蚀倾向和对断裂及应变速率的敏感性,提出了在其表面进行化学镀镍处理的工艺方法。通过正交试验研究了基础化学镀镍液的主要成分对镀层性能的影响,利用扫描电子显微镜、INCA型能谱仪以及显微硬度计等分析了化学镀镍层的表面形貌、组成成分、镀层硬度等特性。研究结果表明,铝锂合金表面进行化学镀镍的可行性工艺为:15 g/L硫酸镍、25 g/L次磷酸钠、30 g/L醋酸钠、20 g/L乳酸、5 g/L硼酸、0.5~1.0 mL/L稳定剂,1.0~2.0 mL/L光亮剂,θ为85℃,施镀时间t为60 min。该工艺能在铝锂合金表面获得结合力良好、耐蚀性较好的化学镀镍层,镀镍层表面晶粒均匀细致,与基体结合力达1级,可耐中性盐雾试验时间48 h以上。