超音速火焰喷涂NiCr-Cr_3C_2涂层的腐蚀磨损行为研究

利用球-盘式往复摩擦试验机和电化学工作站对NiCr-Cr_3C_2涂层和基体进行测试,分析在不同腐蚀性介质中超音速火焰喷涂制备的NiCr-Cr_3C_2涂层的耐腐蚀磨损性能,探究腐蚀磨损机理以及失效形式。结果表明:滑动摩擦破坏试样表面钝化膜,氯离子侵入使得试样的自腐蚀电位负移,腐蚀电流密度增大,摩擦加剧腐蚀,相比较于316L基体,NiCr-Cr_3C_2涂层在去离子水、人工海水和3.5%NaCl溶液中均表现出了良好的耐腐蚀磨损性能。     

316L不锈钢双极板表面聚酰亚胺复合涂层的制备与性能研究

采用共混-喷涂-热压的方法,在316L不锈钢表面上制备了10μm厚不同导电填料含量的石墨/聚酰亚胺(G/PI)、纳米炭/聚酰亚胺(C/PI)复合涂层。通过扫描电镜(SEM)、动电位极化、粘附力测试,以及接触电阻和水接触角测量,比较了含40%～70%(质量分数)填料的两种涂层的各项物理化学性质及其对316L不锈钢耐腐蚀性能的影响。结果表明,C/PI与G/PI涂层均能有效提高316L不锈钢基板的疏水性及耐蚀性,但G/PI涂层与316L不锈钢基板的结合力更好,更适合用作316L不锈钢双极板的耐蚀涂层。在含0.5 mol/L H_2SO_4和5 mg/L F-的溶液中,40%填料含量的G/PI复合涂层的耐蚀性最好,水接触角为86.6°。当组装扭矩为4.0 N·m时,70%G/PI涂层与碳纸的接触电阻为17.24 mΩ·cm~2,较316L不锈钢降低了约80.49%。     

PECVD类金刚石涂层的结构及其摩擦腐蚀行为

采用等离子体增强化学气相沉积技术(PECVD)在316L不锈钢上制备类金刚石(DLC)涂层,系统地研究了所制备类金刚石涂层的表面形貌与结构、不同载荷下的摩擦磨损行为以及NaCl溶液(3.5 wt%)中不同腐蚀时间下的腐蚀行为。研究结果表明：制备的DLC涂层是由sp³键和sp²键杂化形成的非晶碳结构,其中sp²-C含量大于sp³-C,具有典型的类金刚石碳特征;DLC涂层结构致密,表面平滑,粗糙度仅为Ra=12.1 nm,能够与316L不锈钢基体结合紧密;DLC涂层的接触角为59.44°,说明涂层表现出一定的润湿性;摩擦磨损测试结果表明DLC涂层具有良好的润滑效果,摩擦系数能低至0.07～0.16,磨损率低至(3.85～6.71)×10^-7 mm³/(N·m);电化学测试得到DLC涂层自腐蚀电流密度为6.72×10^-6 A·cm^-2,阻抗模值高达7.05×10⁴Ω·cm^-2...     

不锈钢双极板耐腐蚀涂层制备及性能

采用室温恒压电化学氮化技术在316L不锈钢表面成功制备了氮化涂层.通过X射线光电子能谱(XPS)、电化学阻抗(EIS)、动电位极化和接触角测量等方法对涂层的组成、疏水性和耐腐蚀性进行了分析.结果表明:涂层表面主要由铬的氧化物和混合氮化物(CrN+Cr2N)组成.氮化不锈钢接触角由改性前的76.2°提高到106.7°,腐蚀电位较裸钢提高了530 mV,腐蚀电流密度下降了3个数量级,说明氮化涂层能够有效保护不锈钢基底免受腐蚀.此外,在模拟PEMFC阴极环境中进行了10 h的恒电位极化测试,腐蚀电流密度小于1μA cm-2,验证了涂层长期的稳定性.     

三种不同Cr/Al/Ti元素比例的电弧离子镀（Cr/Al/Ti）N膜耐高温氧化性能的比较

用常用的Ti0.33Al0.67靶和Ti0.l50Al0.50靶以及Cr靶,在M2高速钢基体上镀制了三种不同Cr/Al/Ti比例的（Cr,Al,Ti）N涂层。比较了其硬度、结合力;测试了其抗800℃12小时以及900℃1小时氧化性能。结果表明,Cr/Al/Ti为0.55/0.27/0.16的涂层具有更高的硬度,更好的耐高温氧化性能。而结合力基本上没有差别。     

某有机涂层在盐雾环境下性能分析

在Q235基体上制备有机涂层,利用交流阻抗(EIS)测试、SEM(扫描电子显微镜)分析及涂层结合力测试等方法探讨了涂层在盐雾环境下的腐蚀防护性能。结果表明,腐蚀介质到达涂层/基体界面前,有机涂层的耐蚀性能优异,到达基底后涂层阻抗数值急剧减小;经1 200 h SST(盐雾试验)后,涂层内有大量孔隙及裂纹缺陷生成,但涂层与基体的结合强度仍然较高;根据实验结果提出了相应的特征等效电路。     

超音速火焰喷涂316L不锈钢涂层在零件尺寸修复中的应用

为了解决装备核心零部件因磨损、消除腐蚀等带来的尺寸超差问题,制作超音速火焰喷涂316L不锈钢涂层性能试样,对试样涂层的形貌、硬度、耐蚀性开展试验检测研究。结果表明,涂层具有与25Cr3MoA接近的硬度和比30CrMnSiNi2A更好的耐蚀性能。由此,提出采用超音速火焰喷涂316L不锈钢涂层进行零件尺寸修复,制定了可行的修理方案和技术路线,确定了修理工序和参数,形成了相关技术文件,用于指导零件尺寸修复,并在油泵轴和肩轴两类零件上成功应用和装机验证,其性能良好,质量安全。     

FeCrAl合金表面高温抗氧化陶瓷涂层的制备

用粘结料与Cr2O3制成料浆,用喷涂涂覆于FeCrAl合金表面,在空气中1 300℃熔烧制备了耐高温（1 200℃）抗氧化陶瓷涂层.用扫描电子显微镜,电子探针显微分析仪,X射线衍射仪,热膨胀仪等测试手段对涂层以及涂层与基体界面处进行表征.探讨了陶瓷涂层样品高温抗氧化性能的机理,获得了具有良好高温抗氧化性能的陶瓷涂层配方,其粘结料与Cr2O3的质量比为1;0.5.结果表明：在空气中1 200℃,360 h抗氧化实验后,这种涂层样品的氧化质量增加约为基体合金的1/22.揭示了涂层高温抗氧化性能与涂层的组成、显微结构之间的关系.     

基于多弧离子镀TiAlCN涂层的结构、力学及切削性能研究

为提高硬质合金刀具的切削加工性能，研究基于多弧离子镀技术在316L不锈钢及硬质合金(WC/Co)刀具表面制备了C掺杂TiAlCN涂层。首先采用扫描电子显微镜(SEM)、能量色散光谱仪(EDS)、X射线衍射仪(XRD)、拉曼光谱仪(Raman)、X射线光电子能谱仪(XPS)分析了TiAlCN涂层的表面形貌、元素成分、物相结构、碳峰位及化学态信息；然后通过二维触针轮廓仪、三维光学轮廓仪、纳米压痕仪及摩擦磨损试验机表征了TiAlCN涂层的表面粗糙度、三维形貌、纳米硬度、弹性模量及摩擦系数；最后利用高速切削测试验证了TiAlCN涂层的切削加工性能。结果表明：TiAlCN涂层表面致密光滑，无针孔、凹坑等缺陷，表面粗糙度Ra为0.066μm;TiAlCN涂层的物相组成复杂，主要为TiN、Ti(C,N)及Ti₃Al(C,N)，且涂层中形成了以sp²及sp³形式杂化的非晶碳；TiAlCN涂层的纳米硬度(H)、弹性模量(E)及H/E、H³/E²分别为34.18 GPa、398.57 GPa及0....     

HVOF制备的WC-10Co4Cr涂层性能及其在硬密封球阀上的应用

为提高金属硬密封球阀的抗磨损和耐腐蚀性能,采用超音速火焰喷涂(HVOF)工艺,在1Cr13不锈钢钢基体上制备了WC-10Co4Cr涂层。测试了涂层与基体的结合强度以及涂层的显微硬度、气孔率、抗磨损和腐蚀等性能。结果表明:WC-10Co4Cr涂层与粉末的相结构基本一致,涂层的显微硬度高,组织结构致密且与基体的结合强度高;另外,WC-10Co4Cr涂层还表现出较好的抗腐蚀性能和优异的抗磨粒磨损性能。生产实践表明,这些球阀密封性能好,开关灵活且耐磨和耐腐蚀性能良好。     

Inhibiting tribocorrosion damage of Cr/CrxN coatings by multi-layer design

The two-layer and multi-layer Cr/Cr_xN coatings were fabricated on 316 L stainless steel (316 L SS) substrates by the arc ion plating technique. The two-layer Cr/Cr_xN coating was a typical CrN coating with an adhesive Cr layer. And the multi-layer Cr/Cr_xN coating design was in two dimensions. In the first dimension, the multi-layer Cr/Cr_xN coating consisted of alternative Cr/CrN layers with the thickness ratio of 1:5; in the second dimension, the alternative Cr₂N layers with the thickness of 10 nm were inserted in CrN layers. This design was expected to increase transverse interfaces in a smaller scale. The microstructures, mechanical, corrosion and tribocorrosion performances of both Cr/Cr_xN coatings were systematically investigated. The results showed that the special multi-layer design of Cr/Cr_xN coatings improved mechanical, anti-corrosion and anti-tribocorrosion performances. Compared with the two-layer Cr/Cr_xN coating, the reduced tribocorrosion damage of the muti-layer Cr/Cr_xN coating was closely related to the inhibited synergistic effect between electrochemical corrosion and mechanical wear. In conclusion, the multi-layer Cr/Cr_xN coating was more suitable to work as the surface protective coating than the two-layer Cr/Cr_xN coating in seawater.     

Deposition of DLC film with adhesive W-DLC layer on stainless steel and its tribological properties

Tribological properties of a diamond-like carbon (DLC) coating with an adhesive tungsten-containing DLC (W-DLC) layer were investigated. The coatings were deposited onto AISI316L steel substrates and Si wafers using plasma enhanced chemical vapor deposition and tungsten co-sputtering of the metal target. Methane and argon gases were used as the precursor of the coatings. In this study, three types of coatings were evaluated: DLC/W-DLC on AISI316L (DLC-1), DLC/W-DLC on Si wafer (DLC-2), and DLC on Si wafer (DLC-3). The structural characterizations were performed by transmission electron microscopy and tapping mode atomic force microscopy. At the boundary between the W-DLC layer and the AISI316L substrate, microscopic decohesion or delamination was not observed. The surface roughness of the DLC-1 coating was greater than that of the DLC-2 coating. This feature was derived from the surface roughness of the initial surface of the AISI316L substrate. Friction tests were performed using a rotation-type ball-on-flat configuration tribometer. The observed friction of the DLC-1 coating was unstable compared with the DLC-2 or DLC-3 coatings. This was due to wear debris which had risen to the friction surface resulting in unstable friction on the DLC-1 coating. During the friction studies, the top DLC layer was removed from the adhesive W-DLC layer because the adhesive strength at this part was not enough. In order to achieve the low and stable friction of the DLC coating with the W-DLC layer on AISI316L, it is necessary to improve the smoothness of the surface and the adhesion between the DLC coating and the W-DLC layer.     

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.     

Cr–C/h-BN 自润滑复合镀层的制备与摩擦学性能

在三价铬Cr–C镀液中添加1~5 g/L的h-BN自润滑微粒,运用直流电沉积技术在Q235碳素结构钢基体上制备了Cr–C/h-BN复合镀层。利用扫描电镜(SEM)、X射线衍射仪(XRD)、显微硬度计、摩擦磨损试验机等设备分析了h-BN微粒添加量、电流密度等工艺参数对镀层组织和性能的影响。结果表明:在电流密度20 A/dm2,h-BN添加量3 g/L的条件下,可获得h-BN微粒体积分数为6.15%的复合镀层。h-BN微粒的添加改善了Cr–C合金镀层的耐磨性,Cr–C/h-BN复合镀层在室温干摩擦条件下的磨损率减少了22%,平均摩擦因数由原先的0.49降低至0.31。     

Electrochemical behavior of (Cr,W, Al,Ti, Si)N multilayer coating on nitrided AISI 316L steel in natural seawater

AISI 316L steel is often used in materials applied toward nuclear power but are subjected to pitting corrosion in a marine environment. In this study, (Cr, W, Al, Ti, Si)N multilayer coatings were deposited using multi-arc ion plating on the surface of non-nitrided and nitrided AISI 316L steel. The microstructure and corrosion resistance of four different systems were investigated, namely, (i) untreated AISI 316L steel, (ii) plasma nitrided (PN), (iii) coated on an untreated matrix (coating) only, and (iv) coated on nitrided (hybrid) specimens. The phase structures, morphologies, and compositions of the different specimens were characterized using X-ray diffraction, transmission electron microscope, Atomic Force Microscope, scanning electron microscope, X-ray photoelectron spectroscopy, and energy dispersive x-ray spectroscopy. The results show that a thin CrWAlTiSiN multilayer coating, approximately 2.3 μm in thickness, is deposited on the surface of an ~12 μm nitrided layer. Potentio-dynamic polarization and electrochemical impedance spectroscopy were used to evaluate the assessment of the electrochemical behavior in the natural seawater of China's Yellow Sea. The hybrid specimens exhibited excellent corrosion resistance compared to both the nitrided and coated specimens.     

Strongly adherent Al2O3 coating on SS 316L: Optimization of plasma spray parameters and investigation of unique wear resistance behaviour under air and nitrogen environment

Plasma spray deposition of Al₂O₃ is a well-established technique for thick ceramic coatings on various substrates to shield them from corrosion and wear. Owing to its high hardness, aluminum oxide is known to protect stainless steel substrates from wear. However, the plasma process requires optimization for desired coating thickness and adhesion strength. It is also necessary to understand the sensitivity of friction and wear resistance of the deposited coating on exposed environment for evaluation of service life. The study offers comprehensive investigation on plasma process parameters for the development of strongly adherent aluminium oxide coatings on SS 316L substrate. Impact of environment like dry air and dry nitrogen on tribological properties of the coatings was also investigated. Dense adherent coatings of alumina could be deposited on SS 316L at a plasma power of 20 kW with an intermediate bond coat of NiCrAlY to enhance the adhesion properties. The effects of stand-off distance and bond coat thickness on adhesion strength were additionally examined. Further, the coatings were characterised for phase composition, microstructure, microhardness and wear resistance potential. Reciprocating wear tests of the coatings were carried out using ball on disc reciprocating tribometer at different loading conditions (5, 10 and 15 N) at constant (5 Hz) sliding frequency. Unlike the coefficient of friction (COF), wear volume was found to increase with an increase in normal load. These adherent coatings revealed promising properties for the applications where the tribological failure of SS 316L in dry air or dry nitrogen environment is to be controlled.     

Multilayer architecture design to enhance load-bearing capacity and tribological behavior of CrAlN coatings in seawater

Steel materials employed in severe conditions including strong corrosion, high load and multi-factor coupling damages can easily cause incredible degradation until failure, and the protective CrN-based coatings should be one of promising candidates to relieve those damages for the steel equipment or components. In present paper, the monolayer CrAlN and multilayer Cr/CrAlN coatings were successfully deposited on steel substrates by multi-arc ion technology, and their microstructure, mechanical, tribological and corrosion performances were systematically investigated. The results show that the special multilayer Cr/CrAlN coating could possess much better load-bearing capacity and wear resistance than that of monolayer CrAlN coating, which was due to the facts that the multilayer architecture can effectively release the internal stress and inhibit the expansion of defects. Particularly, the multilayer interfaces could effectively prevent the aggressive medium in seawater infiltrating into the inside of coating, and thus the multilayer Cr/CrAlN coating could have higher corrosion resistance compared to monolayer CrAlN coating. As a result, this multilayer Cr/CrAlN coating could achieve excellent combined performances, indicating that it has greatly potential application as protective coating in seawater.     

Effect of carburizing treatment on microstructural,mechanical and tribological performances of Cr doped DLC coating deposited on Ti6Al4V alloy

Cr doped diamond-like carbon (DLC) coating was deposited on the carburized Ti6Al4V alloy (TA) by magnetron sputtering (MS). The physical and chemical characteristics of Cr doped DLC coating were obtained using scanning electron microscope, energy dispersive spectroscope, Raman spectrometer, X-ray photoelectron spectroscopy and Fourier transform infrared, and the mechanical property and adhesion force were analyzed by nanoindenter and scratch tester. The effects of carburizing treatment on the coefficient of friction (COF) and wear mechanism of Cr doped DLC coatings were investigated on a ball-on-disk tribometer. The results show that the adhesion force and mechanical property of Cr doped DLC coating deposited on the carburized TA are higher than those deposited on the original TA. The average coefficients of friction (COFs) of Cr doped DLC coatings deposited on the original and carburized TAs under the dry-friction condition are 0.157 and 0.143, respectively, showing that the carburizing treatment has the obvious effect of friction reduction for the Cr doped DLC coating. The wear mechanism of Cr doped DLC coating deposited on the carburized TA is combined action of abrasive wear and adhesive wear, which are contributed to the enhancement of mechanical property of Cr doped DLC coating by carburization treatment. Furthermore, the average COFs of Cr doped DLC coatings deposited on the original and carburized TAs under the oil-lubrication condition are 0.152 and 0.131, respectively, which are superior to those under the dry-fiction condition. The carburizing treatment promotes the formation of self-repairing carbonyl of Cr doped DLC coating, and the oil-wet characteristic of Cr doped DLC coating with the aromatic aldehyde of CO as the functional group plays the main role of friction reduction.     

Tribological mechanism of micro-arc oxidation coatings prepared by different electrolyte systems in artificial seawater

The micro-arc oxidation (MAO) coatings were prepared in four different electrolyte systems, including mixed acid, phosphate, phosphate-aluminate and phosphate-silicate electrolytes. The friction and wear properties of MAO coatings in ambient air, seawater and four groups of saline solutions related to seawater were investigated. The results showed that the addition of silicate to phosphate could increase the density of the coating. The phosphate-aluminate ceramic layer exhibited the lowest wear rate in various environments. Additionally, the friction coefficient and wear rate of MAO coating in seawater were lower than those in ambient air, which was due to the boundary lubrication effect of seawater. Meanwhile, the presence of divalent metal salts in seawater made its lubricity better than other salt solutions.