Investigation of the Texture of Composite Electrodeposited Chromium–Carbon Coatings

We study the effect of carbon (graphite, black, and various grades of activated coal), introduced into an electrolyte, on the texture of composite chromium deposits. Carbon does not change the crystallographic texture of chromium deposits but substantially affects its perfection. The change in the degree of perfection depends on the concentration and grade of coal, which, obviously, is connected with different actions of impurities.     

超声处理对建筑用EVM表面离子镀DLC涂层组织和摩擦性的影响

通过超声方法处理聚氨基甲酸酯表面,选择脉冲碳离子源,结合阴极放电等离子方法在EVM表面完成DLC涂层的沉积过程,对超声处理过程中温度与时间参数引起的DLC涂层摩擦特性改变进行分析。实验测试研究结果表明:当超声处理的时间延长或者温度升高后,在试样表面形成了更深的条纹,能够显著增强EVM表面发生溶解的能力。DLC涂层在拉曼光谱测试过程中都形成低波数区间中的肩部结构,可以推断其光谱曲线都包含了D峰与G峰,在DLC膜内形成了跟高比例的石墨相。DLC涂层后的表面相对于EVM发生了摩擦系数稳定性下降,该结果表明DLC涂层可以使EVM获得更优耐磨性。当超声温度升高以及时间延长后,试样先发生摩擦系数的略微减小,之后发生逐渐升高。进行超声超声后,试样发生了磨损量的大幅降低,可以获得更致密的DLC涂层。     

金属锌表面超疏水薄膜的制备及其摩擦学性能

通过简单两步法在金属锌表面构筑超疏水薄膜, 锌片首先经N,N-二甲基甲酰胺(DMF)处理在表面构筑微纳结构薄膜, 然后在表面覆盖硬脂酸薄膜以实现超疏水. 采用扫描电子显微镜, 傅里叶红外光谱仪和接触角测量仪等手段表征了超疏水表面的形成机制和表面形貌, 并利用微纳米摩擦磨损试验机研究了超疏水薄膜的减摩耐磨特性. 研究结果发现, 在锌表面形成了一层纳米棒状结构的超疏水薄膜, 水的接触角可达155^o. 超疏水薄膜具有明显的减摩和耐磨特性, 这可归因于DMF处理导致的表面微织构化效应以及脂肪酸自组装薄膜的纳米润滑效应.     

Characterization and Tribological Behavior of Octadecene, Dodecene and Undecenoic Acid Films on Si Substrate

1.IntroductionWith the development of micromachines,the lubri-cation problem of microelectronic-mechanical systems(MEMS)has become more and more important.Con-ventional lubricants such as lubricating grease and oilcannot apply to MEMS owing to their extremely minia-turized size[1].It becomes a pressing problem to developnovel lubricating materials and methods so as to get rid ofthe friction-induced performance degradation and avoidfailure of MEMS devices.Efforts have been made in thisresp…     

摩擦副类型对高速钢表面脉冲激光熔覆CrAlSiN薄膜摩擦性能的影响

以316不锈钢和TC11钛合金作为摩擦副类型,研究其对高速钢表面脉冲激光熔覆CrAlSiN薄膜表面摩擦磨损性能测试分析。研究结果表明:CrAlSiN薄膜表层部位存在许多针孔、凹坑和白色颗粒,并且颗粒尺寸都很大截面区域内生成了许多致密结构的组织,厚度2.5μm左右。薄膜硬度为2416 HV,和基体间的结合力等于53 N,达到良好综合性能。316不锈钢与CrAlSiN薄膜之间对磨后在薄膜表面生成了许多大尺寸磨痕,结合磨痕深度发生了轻微磨损;TC11钛合金与CrAlSiN薄膜进行对磨在薄膜上生成具有较大宽度磨痕,出现了轻度磨损。以不锈钢作为配副材料时,形成了较大的摩擦系数。以TC11钛合金作为配副材料时,发生了严重磨损的现象,跟316不锈钢对磨时形成了深度很大的磨痕。它们磨损机制相近,都是以磨粒磨损和粘着磨损为主。     

镀锌层三价铬钝化膜腐蚀行为的研究

通过盐雾试验、扫描电镜、电化学测试和X射线光电子谱(XPS)等手段,研究了三价铬盐(TC)和三价铬盐加丙烯酸树脂(TCA)两种钝化液制得钝化膜的腐蚀行为及其耐蚀机理.结果表明,热浸镀锌层经TC、TCA钝化处理后,均能有效提高其抗腐蚀能力;SEM发现TC钝化膜表面出现微裂纹,TCA钝化膜表面呈网状的胞状组织覆盖于镀锌层之上,这种致密性好、稳定性高的膜层起到了更好的机械隔离作用,并能抑制钝化膜中微裂纹的产生,所以耐蚀性能大大提高;XPS分析表明,TC及TCA钝化膜层铬是以CrOOH或Cr(OH)3三价存在.此外,TCA膜层中还含有四价C、五价N.     

锌及锌覆盖层户外大气暴露腐蚀行为的研究

户外大气暴露腐蚀造成了损失巨大,研究其腐蚀行为与规律意义重大.通过户外大气暴露腐蚀数据统计分析及腐蚀产物分析,确定了影响锌及锌覆盖层在我国典型地区大气暴露腐蚀行为的最主要的环境因子,在腐蚀动力学、腐蚀机理、腐蚀产物等方面系统研究了锌及锌覆盖层在我国典型地区的大气腐蚀规律.结果表明,相对湿度、SO2、Cl-是影响锌及锌覆盖层在北京、武汉、江津、广州典型地区大气腐蚀行为的主要环境因子.锌及锌覆盖层在上述典型地区大气腐蚀动力学以线性为特征,且腐蚀速率:江津＞广州＞武汉＞北京,与这些地区在试验时间SO2沉积率大小排列次序(江津＞广州＞武汉＞北京)相对应.锌及锌覆盖层在上述典型地区大气暴露主要腐蚀产物为:Zn4SO4(OH)6·5H2O,另含有少量Zn5Cl2(OH)8·H2O及Zn4Cl2(OH)4SO4·5H2O.     

Fabrication and Characterization of Electrodeposited Ni-SiC-h/BN Composite Coatings

Ni—SiC—h/BN composite materials were prepared by electrodeposition technique with the dispersion of SiC（10 g/L） and h/BN nanosheets（10 g/L） in a nickel sulfamate electrolytic bath.Different ratio of sodium dodecyl sulfate（SDS） and cetyltrymethyl ammonium bromide（CTAB） surfactants were used to evaluate the effect of surfactants on the properties of the electrodeposited composite coatings.The coating samples were characterized by scanning electron microscopy,X-ray diffraction,Vickers microhardness test,scratch and tribology tests.The results revealed that the co-deposition of nanoparticles was significantly influenced by surfactants during electrodeposition process.Pyramidal or polyhedral nickel crystallites were observed at higher ratio of SDS/CTAB while smaller oval grains with refined surface morphologies were obtained at lower ratio of SDS/CTAB surfactants.In addition,wt%of particles co-deposition was increased,and Vickers microhardness,wear and coefficient of friction of the electrodeposited composite coatings were improved at increased CTAB and decreased SDS contents in the electrolyte during electrodeposition process.     

火焰喷涂FEP涂层的制备及其摩擦行为

利用火焰喷涂设备制备了FEP涂层,并对涂层的组成结构和摩擦学性能进行了评价.研究结果表明:经过对磨屑和FEP原料的红外测试,发现涂层无明显的降解和氧化;FEP涂层在与CCr15钢球对磨时,表现出优良的摩擦学性能.涂层的摩擦系数随着载荷的增大而降低;在相同载荷下,随着速度的增加,摩擦系数有逐步降低的趋势;相同载荷下,FEP涂层在低速情况下的磨损呈现出明显的粘着磨损迹象;在高速情况下,涂层迅速发生塑性变形,对偶与涂层之间类似抛光作用.     

电化学沉积方法对聚苯胺涂层抗腐蚀性能及电化学性能的影响

聚苯胺涂层的电化学特性及耐蚀性与其合成方法及工艺有着密切的关系.在以硫酸为掺杂剂的合成溶液中采用循环伏安和恒电流方法在304不锈钢表面沉积出了聚苯胺涂层.用扫描电镜和电化学方法研究了聚苯胺涂层的表面形貌、抗腐蚀性能和电化学性能.结果表明:聚苯胺涂层表面为多孔结构;开路电位-时间曲线表明,在腐蚀介质中,2种聚苯胺涂层均提高了304不锈钢的腐蚀电位,电化学阻抗谱结果表明,2种聚苯胺涂层在腐蚀初期反应均受扩散步骤控制,对腐蚀介质有一定的阻挡作用,但恒电流方法制备的聚苯胺在浸泡24 h后,表现为基体金属的阻抗谱特征.因此,相对于恒电流方法,循环伏安方法制备的聚苯胺对304不锈钢的钝化能力更强,可为基体提供更好的保护.     

不锈钢表面电沉积耐腐蚀膜层的研究进展

不锈钢因其优异的耐蚀性、导电导热性和机械加工性能而广泛应用于众多领域.为避免不锈钢在使用过程中的腐蚀破坏,在基体表面制备耐腐蚀膜层是主要的防护措施.首先结合近年来不锈钢表面电沉积法制备耐腐蚀膜层的研究现状,对不锈钢表面单层耐腐蚀膜、多层耐腐蚀膜及含掺杂物改性复合膜3种膜层的研究进展进行了概述;在此基础上,从膜层对基体的...     

锌基体疏液表面的制备及润湿行为

采用盐酸水溶液化学刻蚀和水热反应的方法在锌基体上构建微纳米粗糙结构,再经全氟辛酸修饰,制备疏液表面。通过X射线衍射仪、扫描电镜、红外光谱仪和接触角测量仪对试样表面的相组成、微观形貌、化学成分及润湿性进行表征。结果表明:试样的亚微米结构表面生长出一层ZnO纳米棒,在低表面能物质的共同作用下表现出良好的抗水流冲击性和稳定性。当盐酸浓度为1.0mol/L,水热反应温度为95℃时,ZnO纳米棒的生长形态最优,水和花生油在疏液表面的最大接触角分别为154.65°和144.65°,滚动角小于10°。     

Thermal Treatment Optimization of Electrodeposited Hydroxyapatite Coatings on Ti6Al4V Substrate

Thermal behavior of electrodeposited hydroxyapatite (HAP) coating on a titanium alloy (Ti6Al4V) is investigated in order to optimize the heat treatment conditions for this prosthetic material. The synthesized coatings are annealed in air atmosphere at 400, 600, 800, and 1000 °C, and then characterized by X‐ray diffraction (XRD) and selected area electron diffraction (SAED) for structure and phases analysis. Scanning and transmission electron microscopy associated to energy dispersive X‐ray microanalysis (SEM‐EDXS and STEM) are used for morphology and composition analysis. The results show that when the electrodeposited coating is annealed at temperatures greater than 600 °C, a well‐crystallized HAP is obtained with a notable change of its morphology. However, at these temperatures the surface of Ti6Al4V alloy (uncoated zones of the implant) is deteriorated by the formation of a thick surface oxide layer. Therefore, we limit the heat treatment temperature for the electrodeposited coatings on a Ti6Al4V alloy at 550 °C. At this optimized temperature it is demonstrated that the link between the coating and the substrate is improved and the crystallinity of the coating is controlled which make it well bioactive.     

Substrate Effects on the High-Temperature Oxidation Behavior of Thermal Barrier Coatings

The high-temperature oxidation behaviors of the NiCrAlYSi/P-YSZ thermal barrier coatings (TBCs) produced by electron beam-physical vapor deposition (EB-PVD) on directionally solidified (DS) and single crystalline (SC) Ni-based superalloy substrates were investigated. The cross-sectional microstructure investigation, isothermal and cyclic oxidation tests were conducted for the comparison of oxidation behaviors of TBCs on different substrates. Although TBC on DS substrate has a relatively higher oxidation rat...     

45钢表面激光熔覆NiCrBSi涂层的组织和摩擦磨损性能

采用激光熔覆技术在45钢表面制备NiCrBSi合金涂层,利用EPMA,SEM和TEM分析了激光熔覆层的微观组织,测试了激光熔覆层在不同环境气氛压力下的摩擦磨损性能.结果表明:激光熔覆层由熔覆区(CZ)、结合区(BZ)和基底热影响区(HAZ)三个区域组成.熔覆区的组织是在γ-Ni树枝晶和γ-Ni Ni3B共晶的基体上分布着细小的CrB颗粒和Cr7C3树枝晶,结合区是基底材料和熔覆材料的混熔区,呈定向凝固特征,基底热影响区为针状马氏体组织.激光熔覆层的摩擦磨损性能与环境气氛压力密切相关,随环境气氛压力的降低,摩擦系数增大,磨损量减少.     

Characterization of the Tribological Behavior of Different Tool Coatings and Dry Lubricant for High-Strength Aluminum Alloys at Elevated Temperatures

The use of high-strength aluminum components in automotive manufacturing offers the opportunity to reduce vehicle weight significantly and provide new lightweight potentials. In the past, the so-called hot forming and quench process (HFQ) successfully demonstrates the potential for the production of complex-shaped components made out of age-hardenable high-strength aluminum alloys. Currently, no method permits wear-free quench forming without the use of lubricants. To fulfill the increasing ecological and economic requirements, it is necessary to identify wear-reducing techniques to promote this forming technology in the future. This contribution investigates the interaction of lubricant and tool coatings on the tribological performance during quench forming of the high-strength aluminum alloy AA7075 at elevated temperatures. For this purpose, the tribological behavior is investigated using both, flat strip drawing tests and deep drawing operations. Subsequently, the component quality is compared and discussed. The results demonstrate that tool coatings are effective for the production of high-strength components in the HFQ process with minimal or even no lubrication and thus provide ecological as well as economic advantages.     

氮气流量对直流磁控溅射Zr-B-O-N薄膜摩擦学行为的影响

通过向ZrB₂薄膜中添加N和O元素,利用纳米复合结构和“预氧化”机制有望提高薄膜韧性、耐磨性能和耐热能力,本文系统研究了氮气流量对Zr-B-O-N薄膜摩擦学行为的影响。采用直流反应磁控溅射技术研制了ZrB₂薄膜和不同成分的Zr-B-O-N薄膜,利用扫描电镜观察薄膜的表面形貌,销盘式摩擦试验机测试薄膜的摩擦磨损性能,分析磨损失效机理。研究结果表明:在ZrB₂薄膜中添加N和O元素后,耐磨性能得到明显提高,随着氮气流量的增加,薄膜表面质量越来越好。结合力学性能测试结果,发现硬度不是影响薄膜耐磨性能的唯一要素,H/E^*值越大,薄膜抗磨损能力越强。当氮气流量比为5%时,尽管Zr-B-O-N薄膜硬度只有15 GPa,却具有最低的磨损率1.65μm³/N·mm。该工作为定量探讨薄膜力学参量与抗磨损性能的关系提供了重要实验依据。     

电沉积镍-羟基磷灰石复合涂层的研究

在镀镍液中加人少量的Ca(NO3)2、NH4H2PO4，在钛基体上实现在电沉积过程中羟基磷灰石(HA)和Ni的共沉积，实验探讨了电流密度、钙、磷浓度对涂层表面形貌、HA含量及涂层结合强度的影响。实验结果表明：涂层中HA的含量随电流密度和钙、磷浓度的增加而提高，但涂层结合强度先增大后减小，Ni-HA复合涂层的结合强度明显高于纯HA涂层的结合强度。通过控制适当的电沉积条件，在[Ca^2 ]=0．01mol／L，电流密度jc=20—30mA/cm^2时，可以制得HA分散较为均匀、结合强度较高的Ni-HA复合涂层。