TiCN涂层的制备及其微观结构和性能

采用直流磁控溅射法在AZ31镁合金上制备了TiCN涂层.采用X射线荧光光谱仪、扫描电镜和X射线衍射仪表征了涂层的化学成分、表面形貌和物相,并采用电化学阻抗谱、浸泡试验、显微硬度测试和磨损试验考察了基体偏压(-40、-60和-80 V)对涂层性能的影响.结果表明,涂层由TiCN和TiN组成.随着负偏压增大,涂层中Ti、C...     

电压对6061铝合金微弧氧化陶瓷膜性能的影响

研究了电压对6061铝合金微弧氧化陶瓷膜相结构、微观形貌和耐磨性的影响。结果表明,随工作电压增大,微弧氧化陶瓷膜的厚度增大,表面粗糙度和显微硬度先增大后减小,耐磨性先变好后变差。电压为500 V时,所得的微弧氧化陶瓷膜厚度为12.5μm,显微硬度最高(407 HV),耐磨性最佳。     

电压对复合氧化法制备含钙磷的多孔氧化钛涂层结构的影响

为了分析电压对复合氧化法(即预阳极氧化和微弧氧化复合处理)制备多孔二氧化钛涂层的结构和性能的影响，利用X射线衍射、扫描电镜、显微硬度计、涂层划痕仪等对涂层的结构、形貌、元素组成、硬度及结合强度进行了观察测试。结果表明：电压对多孔二氧化钛涂层的结构和性能有很大影响，电压较低时，涂层由纯锐钛矿型二氧化钛组成；电压较高时，涂层由锐钛矿和金红石混合型二氧化钛组成；随着电压的增加，涂层表面最大微孔孔径增大，凹凸起伏变得明显，显微硬度增加，涂层的钙磷原子比也发生了变化。当电压为250，300，350和400V时，涂层中的钙磷摩尔比分别为1．27，1．86，1．52和1．82。在300 V电压下可得到结构和性能较为理想多孔二氧化钛梯度涂层。     

膜厚对(Ti,Al)N涂层微结构、机械性能及切削特性的影响

利用蒸发与磁控溅射二元组合源设备,通过控制沉积时间在钨钴类硬质合金螺纹刀表面制备了不同膜厚的(Ti,Al)N涂层。采用X射线衍射仪、扫描电镜、能谱仪、维氏显微硬度计、洛氏硬度计和摩擦试验机考察了涂层厚度对涂层微观结构、表面形貌、元素组成、显微硬度、膜-基结合力及摩擦磨损性能的影响,并通过切削40Cr钢材研究了涂层刀具的切削特性。结果表明,沉积6 h所得涂层(膜厚约5.0μm)的复合硬度(涂层+基材的显微硬度)显著高于沉积2 h(膜厚约1.8μm)所得涂层,但膜-基结合力更弱,磨耗速率更快。     

二硫化钼改性石墨基复合减摩涂层的摩擦磨损特性

以二硫化钼和石墨作为固体填料,聚酰亚胺作为黏结剂制备了耐磨减摩涂层,并研究了二硫化钼与石墨在聚酰亚胺黏结剂中的协同作用。测试涂料的黏度、复合涂层的显微硬度、摩擦因数以及磨损率,通过扫描电子显微镜(SEM)研究磨痕的微观形貌,研究基本物理性能及耐磨性,用SEM和三维形貌仪观察磨损轨迹的形貌。结果表明,随着二硫化钼比例的增大,黏度逐渐升高;二硫化钼与石墨的质量比为6∶4时,硬度最高为41.6 HV,二硫化钼的含量继续增加时,显微硬度开始下降;当二硫化钼与石墨质量比为2∶8时,摩擦因数最低为0.18～0.19之间,且涂层磨损率为1.275 6×10~(-4)mm~3/(N·m),涂层的摩擦磨损特性最佳。     

PH17-4不锈钢表面电火花沉积WC–20Ni涂层及其表征

以WC–20Ni作为电极,氩气作为保护气体,通过改装的HB-06型电火花堆焊修复机在PH17-4不锈钢基体表面沉积了WC–20Ni涂层。以涂层厚度为指标,通过单因素试验获得最佳工艺参数为:电压125 V,频率660 Hz,电容120μF,沉积时间3 min。采用扫描电镜、能谱仪和显微硬度计分别表征了沉积层的表面形貌、成分和显微硬度。在最佳工艺参数下,制得的沉积层组织连续、致密,与基体冶金结合且厚度均匀,约为30μm。随着距表面距离的增大,沉积层的显微硬度逐渐降低。     

电压对电刷镀三价铬镀层性能的影响

在45钢表面电刷镀得到三价铬镀层,镀液组成和工艺条件为:Cr2(SO4)36H2O 0.4 mol/L,甲酸铵0.5 mol/L,氨基乙酸0.5 mol/L,H3BO30.6 mol/L,NaH2PO2 H2O 0.3 mol/L,pH=1.5,温度50°C,镀笔移动速率15 cm/s。研究了电压对镀铬层显微结构、表面粗糙度、厚度、显微硬度和耐磨性的影响。随电压增大,镀层厚度增大,显微硬度和耐磨性均先提高后降低。电压为14 V时,镀层的表面平整,粗糙度为2.387μm,显微硬度为602 HV,耐磨性最好。     

负偏压对TiAlN涂层微观组织和性能的影响

采用多弧离子镀技术在钢基体上沉积了TiAlN涂层,研究了负偏压对TiAlN涂层的表面形貌、物相变化和力学性能的影响。结果表明,随着负偏压的增大,涂层表面溶滴颗粒的大小和数量均减小,晶格常数随Al含量的减少而增加,从-50V的0.413nm到-200V的0.422nm。同时负偏压的增大,增强了离子束对涂层和基体的轰击效应,提高了涂层抵抗塑性变形的能力,使得涂层的硬度和界面结合力得到改善。     

电压对快速刷镀铁镀层形貌及硬度的影响

使用电刷镀法在球墨铸铁上快速刷镀铁,采用不同刷镀电压进行刷镀实验。采用扫描电镜和显微硬度计对镀铁层的表面形貌和显微硬度进行观察和测定,分析刷镀电压对铁镀层表面形貌及显微硬度的影响。结果表明,电压为4 V时,镀层表面裂纹较多,显微硬度较低;6 V时镀层表面平整但有少量气孔,是由于刷镀时氢气聚集并未排出所致,显微硬度增大;继续升高电压至9 V时镀层表面有大量微凸体且表面粗糙,显微硬度降低。     

pH值对B_4C微粒复合镀铁层性能的影响

利用自制的不对称交-直流电镀电源进行低温复合镀铁。研究了pH值对B_4C微粒复合镀铁层的显微硬度、沉积速率及耐磨性的影响。结果表明:当pH值为1.0时,复合镀铁层具有最佳的综合性能;随着pH值的降低,复合镀铁层的显微硬度下降,沉积速率减慢,磨损量增大;随着pH值的升高,复合镀铁层的显微硬度升高,沉积速率减慢,磨损量增大。     

Characterisation of in-situ reactive plasma-sprayed nano-(Ti,V)N composite ceramic coatings with various V concentrations

The effect of V concentration on the microstructure and phase composition of nano-(Ti, V)N composite ceramic coatings prepared by in-situ reactive plasma spraying of mechanically mixed Ti–V powders were investigated using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, X-ray energy dispersive spectroscopy, and transmission electron microscopy. The microhardness, toughness, wear resistance, and strengthening mechanism of the prepared nano-(Ti, V)N coatings were measured and analysed. The results showed that the nano-(Ti, V)N coating comprised a large proportion of nano-(Ti, V)N grains, which was the solid solution of TiN and VN. All the V atoms completely entered the TiN lattice and the solubility limit of V in TiN is approximately 25 wt%. The grains of the (Ti, V)N (25 wt% V) coating had a face-centred cubic structure and a large quantity of twins; they were primarily equiaxed grains morphology with a few columnar grains. From comparing the experimental statistics, the (Ti, V)N (25 wt% V) coating displayed the highest microhardness (1952 ± 78.5 Hv) and the most even dispersion but a slightly lower toughness compared with the (Ti, V)N (35 wt% V) coating. The (Ti, V)N (25 wt% V) coating with a dense microstructure obtained a high microhardness due to dislocation strengthening, fine grain strengthening, and solid solution strengthening (from the solid solution of VN in TiN). Furthermore, a lower friction coefficient and wear volume loss indicated that the (Ti, V)N (25 wt% V) coating had superior tribological properties and great potential as a wear resistant coating.     

多弧离子镀(Ti,Cr)N镀层耐蚀性研究

采用多弧离子镀技术在高速钢表面制备了(Ti,Cr)N镀层,通过电化学工作站对镀层的塔菲尔曲线进行测试,分析镀层的耐腐蚀性,并采用质量变化法对电化学测试结果进行了验证。利用扫描电子显微镜观察了(Ti,Cr)N镀层腐蚀前后的微观形貌。结果表明,随电流比例ICr/ITi的增大,(Ti,Cr)N镀层表面晶粒尺寸逐渐减小。当ICr/ITi为90 A/60 A时,基体的自腐蚀电位由-0.750 V正移至-0.534 V,基体的腐蚀速率降低85.67%,耐蚀性提高。基体的腐蚀主要为点蚀和均匀腐蚀,(Ti,Cr)N镀层主要为小孔腐蚀。     

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.     

Influence of negative bias voltage on microstructure and property of Al-Ti-N films deposited by multi-arc ion plating

In this study, we systematically investigated the effects of negative bias voltage on the composition, deposition efficiency, microstructure, and mechanical properties of multi-arc ion plated (MAIP) AlTiN films. The films were deposited on high-speed steel substrates by MAIP at various negative bias voltages. The results indicated that the Al content [Al/(Al+Ti) ratio] and the deposition efficiency were significantly altered by the application of negative bias voltages. X-ray photoelectron spectroscopy analysis showed that the AlTiN films were composed of Ti–N and Al–N bonds. The macroparticles (MPs) on the film surface decreased with increasing negative bias voltage. We also discussed the different types of MPs found on the films and their influence on the process of determining the hardness of the films. The microhardness of the films depends on the negative bias voltages. The films deposited at −250 V exhibited a maximum hardness of ~45 GPa. The adhesion and frictional tests revealed that the film deposited at −150 V demonstrated the highest cracking resistance, the best adhesion under a critical load of 78 N, highest adhesion strength, and the lowest and stablest coefficient of friction at 0.23.     

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.     

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.     

Design and development of TiC-reinforced 410 martensitic stainless steel coatings fabricated by laser cladding

AISI 410 martensitic stainless steel (MSS) coatings, reinforced with TiC ceramic particles of varying contents (0, 5%, 10% and 15%), have been fabricated by laser cladding technology for the first time in this study. The microstructure evolution and properties of the laser-cladded specimens are carefully investigated by advanced techniques, including XRD, SEM, TEM, EDS, a micro-hardness tester and a ball-on-disc tribological tester. The obtained results show that the as-cladded 410 MSS coating is mainly composed of coarse lath martensite (M), a few austenite (A) and M₂₃C₆. After addition of TiC ceramic particles, the lath-shaped M is significantly refined, meanwhile the nano-sized Ti-enriched ceramic precipitates (TiC and Ti(C,N)) are formed in the composite coatings. However, microcracks and pores occur in the laser-cladded coating with addition of TiC up to 15%. It is found that both the microhardness and wear resistance of the coatings are enhanced with an increasing TiC content, and the 10% TiC-reinforced coating exhibits the optimal comprehensive performance, with much higher microhardness and wear resistance in comparison to the TiC-free MSS coating. The remarkable properties of the TiC-reinforced 410 MSS coatings can be mainly ascribed to the synergistic effects of microstructural refinement, nano-precipitation hardening and second-phase strengthening.     

Hot filament chemical vapour deposition and wear resistance of diamond films on WC-Co substrates coated using PVD-arc deposition technique

Different Cr- and Ti-base films were deposited using PVD-arc deposition onto WC-Co substrates, and multilayered coatings were obtained from the superimposition of diamond coatings, deposited on the PVD interlayer using hot filament chemical vapour deposition (HFCVD). The behaviour of PVD-arc deposited CrN and CrC interlayers between diamond and WC-Co substrates was studied and compared to TiN, TiC, and Ti(C,N) interlayers. Tribological tests with alternative sliding motion were carried out to check the multilayer (PVD + diamond) film adhesion on WC-Co substrate. Multilayer films obtained using PVD arc, characterised by large surface droplets, demonstrated good wear resistance, while diamond deposited on smooth PVD TiN films was not adherent. Multilayered Ti(C,N) + diamond film samples generally showed poor wear resistance.Diamond adhesion on Cr-based PVD coatings deposited on WC-Co substrate was good. In particular, CrN interlayers improved diamond film properties and 6 μm-thick diamond films deposited on CrN showed excellent wear behaviour characterised by the absence of measurable wear volume after sling tests. Good diamond adhesion on Cr-based PVD films has been attributed to chromium carbide formation on PVD film surfaces during the CVD process.