45~#钢表面织构上硬脂酸薄膜减摩性能的研究

本文中提出了一种在45#钢表面构筑具备优异减摩耐磨性能的薄膜的简易方法.首先采用高浓度氢氧化钠溶液在钢表面制备沟槽状表面织构,然后沉积硬脂酸分子得到减摩耐磨薄膜.用扫描电子显微镜、原子力显微镜、接触角测量仪、X射线光电子能谱仪以及X射线衍射仪等手段表征了薄膜的形成机制、表面形貌和化学组分,并利用微纳米摩擦磨损试验机研究薄膜在干摩擦条件下的减摩耐磨特性.研究结果发现,在经化学刻蚀形成织构的钢表面所沉积的硬脂酸薄膜具有优异的减摩耐磨性能.     

磷酸锌表面脂肪酸自组装单分子膜的制备及其摩擦学性能研究

采用水热法在锌片上一步合成磷酸锌薄膜,随后在表面沉积硬脂酸单分子膜以实现高疏水.利用扫描电子显微镜(SEM)、X-射线衍射(XRD)及摩擦磨损试验机(UMT-3)对制得样品的表面形貌、结构组份及摩擦学性能进行了表征,并利用红外光谱仪(IR)对硬脂酸修饰机理进行了研究.研究结果发现:在水热处理导致的磷酸锌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的联合作用下,在锌表面构筑的高疏水膜具有明显的减摩和耐磨特性.     

链长对离子液体超薄膜微/纳摩擦学性能的影响

采用浸渍-提拉法在单晶硅片表面成功制备了纳米厚度的具有不同烷基链长的离子液体超薄膜,系统考察了烷基链长对离子液体超薄膜微/纳摩擦学性能的影响.用Mettler热重分析仪测定了离子液体在氮气气氛条件下的热稳定性,采用多功能X射线光电子能谱分析了离子液体超薄膜表面的化学组分,并用接触角仪测定了其亲/疏水性质,薄膜的表面形貌、黏着和纳米摩擦学性质采用原子力显微镜进行了测定,采用微摩擦试验机评价了薄膜的微摩擦学性质.结果表明:离子液体的侧链烷基链长对其作为超薄膜的纳米摩擦学和黏着性质有重要的影响,随着烷基链长的增加,黏着力和纳米摩擦力大幅度降低,但对其微摩擦性能影响不大.同时根据试验结果提出了离子液体超薄膜减摩抗磨机理.     

纳米AlOOH及纳米Fe_3O_4粒子在液体石蜡中的摩擦学性能研究

采用四球摩擦磨损试验机对表面修饰的纳米AlOOH粒子及纳米Fe3O4粒子在液体石蜡中的摩擦学性能进行了对比研究.结果表明:这2种纳米粒子均能提高液体石蜡的减摩耐磨性能和PB值,纳米AlOOH粒子因具有层状结构,表现出更好的减摩耐磨性能,随着纳米粒子粒径的增大,其减摩耐磨的最佳浓度出现升高的趋势.对磨斑表面的SEM、AFM和XPS分析结果表明,纳米粒子能沉积在摩擦副表面,减少摩擦副表面微凸体的直接接触,从而减少微凸体之间的犁削和黏着.     

中频磁控溅射沉积含铝类金刚石碳膜结构及其摩擦磨损性能研究

采用中频磁控溅射技术在单晶硅表面制备含铝类金刚石(Al-DLC)薄膜,利用原子力显微镜、X射线光电子能谱仪、红外光谱仪、纳米压痕仪和微摩擦磨损试验机等考察薄膜表面形貌、结构及其摩擦磨损性能.结果表明:所制备的Al-DLC薄膜均匀、致密,表面粗糙度小,应力较低,硬度较高;薄膜与Si3N4陶瓷球对摩时显示出良好抗磨减摩性能;加基底偏压所制备薄膜的摩擦系数明显降低, 耐磨寿命显著提高.     

Mg-Mn-Ce镁合金表面功能纳米有机薄膜的制备与摩擦学特性

通过有机镀膜技术在Mg-Mn-Ce镁合金表面制备了有机薄膜,采用接触角测量仪测定了有机薄膜的蒸馏水接触角,使用椭圆偏振光谱仪测试了薄膜厚度,利用X射线光电子能谱仪（XPS）表征了薄膜表面典型元素的化学状态,使用原子力显微镜（AFM）观察了薄膜的表面形貌,并借助于纳米划痕测试仪评价了薄膜在微载荷下的摩擦学特性。研究结果表明：有机镀膜后镁合金表面形成了有序的纳米有机薄膜,有机薄膜与蒸馏水的接触角为108.6 °（未处理镁合金基体与水的接触角为45.8 °）,实现了亲水到疏水功能特性的转变;未处理镁合金基体的摩擦系数为0.127,有机镀膜后镁合金的摩擦系数为0.078,因此疏水性纳米薄膜能够有效降低摩擦系数。     

链长对离子液体纳米薄膜微/纳摩擦学性能的影响

采用浸渍－提拉法在单晶硅片表面成功制备了纳米厚度的具有不同烷基链长的离子液体超薄膜，系统考察了烷基链长对离子液体超薄膜微/纳摩擦学性能的影响。用Mettler热重分析仪测定了离子液体在氮气气氛条件下的热稳定性，采用多功能Ｘ射线光电子能谱分析了离子液体超薄膜表面的化学组分，并用接触角仪测定了其亲／疏水性质，薄膜的表面形貌、粘着和纳米摩擦学性质采用原子力显微镜进行了测定，采用微摩擦试验机评价了薄膜的微摩擦学性质。结果表明：离子液体的侧链烷基链长对其作为超薄膜的纳米摩擦学和粘着性质有重要的影响，随着烷基链长的增加，粘着力和纳米摩擦力大幅度降低，但对其微摩擦性能影响不大。同时根据试验结果提出了离子液体超薄膜减摩抗磨机理。     

等离子体辅助球磨制备表面修饰纳米TiO2的摩擦学性能分析

以季铵盐和月桂酸钠为过程处理剂,利用等离子体辅助球磨制备表面修饰纳米TiO_2粉体,并测试其摩擦学性能.结果表明:在等离子体的热爆效应及脉冲电子轰击效应的协同作用下,辅助球磨11 h制备的表面修饰纳米TiO_2粉体粒径在20 nm左右,晶型发生由锐钛矿型向金红石型的转变.等离子体辅助球磨使得纳米TiO_2获得了良好的亲油疏水表面特性,在40CA船用润滑油中表现出稳定的分散性.由于纳米TiO_2粉体的"微轴承"作用,复合润滑油的摩擦系数降低,摩擦副的磨损失重量减少.纳米TiO_2粉体在摩擦过程中容易吸附沉积在摩擦副表面并修补磨痕,使得复合润滑油具备良好的减摩及自修复性能.     

钛合金表面掺金属类金刚石薄膜的摩擦磨损性能研究

采用阳极层流型矩形气体离子源结合非平衡磁控溅射法在钛合金基体表面制备掺金属类金刚石(Me-DLC)薄膜,通过X射线光电子能谱仪、俄歇微探针、表面形貌仪及扫描电子显微镜等对薄膜结构进行表征,用SRV型摩擦磨损试验机评价其摩擦磨损性能.结果表明,类金刚石薄膜可以提高钛合金基体的承载能力和硬度,对基体材料起到有效的耐磨减摩作用,掺钨类金刚石薄膜的硬度及膜/基结合强度较高,具有良好的耐磨减摩性能,且在膜层承载能力范围内,载荷越高,DLC梯度薄膜的摩擦系数越小.     

低温溶胶凝胶法制备TiO2薄膜减摩性能的研究

采用溶胶-凝胶法并结合水热后处理技术在金属铜表面制备了TiO_2薄膜,利用扫描电子显微镜、X射线衍射对薄膜的表面形貌、晶型进行了表征,通过极化曲线研究了TiO_2薄膜在3.5%NaCl水溶液中的耐蚀性能,并考察了TiO_2薄膜的摩擦磨损性能.结果表明:170℃下水热处理后得到的TiO_2薄膜与480℃直接焙烧处理制备的TiO_2薄膜的表面形貌和晶型存在着明显差异,前者具有较低的摩擦系数和更长的耐磨寿命,同时在3.5%Na Cl溶液中的耐蚀性能也明显优于后者.     

Nano-tribological study on a super-hydrophobic film formed on rough aluminium substrates

A novel super-hydrophobic stearic acid (STA) film with a water contact angle of 166^o was prepared by chemical adsorption on aluminum wafer coated with polyethyleneimine (PEI) film. The micro-tribological behavior of the super-hydrophobic STA monolayer was compared with that of the polished and PEI-coated Al surfaces. The effect of relative humidity on the adhesion and friction was investigated as well. It was found that the STA monolayer showed decreased friction, while the adhesive force was greatly decreased by increasing the surface roughness of the Al wafer to reduce the contact area between the atomic force microscope (AFM) tip and the sample surface to be tested. Thus the friction and adhesion of the Al wafer was effectively decreased by generating the STA monolayer, which indicated that it could be feasible and rational to prepare a surface with good adhesion resistance and lubricity by properly controlling the surface morphology and the chemical composition. Both the adhesion and friction decreased as the relative humidity was lowered from 65% to 10%, though the decrease extent became insignificant for the STA monolayer. The project supported by the National Natural Science Foundation of China (50375151, 50323007, 10225209) and the Chinese Academy of Sciences (KJCX-SW-L2)     

单晶硅表面全氟聚醚润滑膜的制备及摩擦特性研究

利用浸涂技术在单晶硅基片上成功地制备出极性全氟聚醚润滑膜,在DF－PM型动－静摩控系数精密测定装置上考察了润滑膜的摩擦特性,并采用接触角测定仪和X射线光电子能谱仪对润滑膜的表面性质和化学状态进行了表征。结果表明,与基片相比,经烘烤处理后的全氟聚醚润滑膜同钢对摩擦系数显著降低,经60次摩擦后,摩擦系统迅速增大到0．22左右,此时润滑膜被磨穿;此后摩擦系数缓慢增加,当摩擦次数达到200次左右时,摩擦系数稳定于0．42附近,低于单晶硅片相应的摩擦系数,这可能是由于基片表面的全氟聚醚在滑动过程中向钢球表面发生转移所致。     

Role of surface roughness in the magnesite flotation and its mechanism

Surface roughness has a significant influence on mineral flotation. The assisting effect of surface roughness on minerals flotation is extensively investigated from its physical properties (e.g., the existing form of asperity and its size), however, the associated effect on mineral flotation based on the differences in surface chemical property caused by surface roughness has been rarely touched. With such a question in mind, in this study, we investigated the flotation recoveries of two batches of magnesite particles with varying degree of surface roughness produced by two different mills, and associated the flotation performances to their surface chemical properties (amount of adsorption sites for the collector) via a series of detections, including Scanning Electron Microscope-Energy Dispersive Spectrometry (SEM-EDS) observations, X-ray photoelectron spectroscopy (XPS) analysis, adsorption capacity tests, and contact angle measurements. Finally, we concluded that rougher magnesite particles could provide more active sites (Mg²⁺) for a larger capacity of sodium oleate (NaOL), thereby improving the hydrophobicity and floatability.     

紫外照射对FOTS自组装分子膜表面特性和摩擦特性的影响

利用自组装技术在硅基底制备FOTS自组装分子膜,对FOTS自组装分子膜进行紫外照射.采用接触角测量仪、原子力显微镜(AFM)、傅里叶红外变换光谱仪(FTIR)、X光电子能谱(XPS)和多功能摩擦磨损试验机(UMT)评价薄膜的表面特性和摩擦学特性.结果表明:FOTS自组装分子膜的蒸馏水接触角为109°.紫外照射导致C元素被O₃氧化,形成亲水的-COOH末端基团,使其接触角变小,表面粗糙度增大.在微载荷下,FOTS自组装分子膜和经不同时间紫外照射的FOTS自组装分子膜均可降低硅基底的摩擦和磨损.紫外照射后使FOTS自组装分子膜的摩擦系数增大,磨损加剧,这与其表面结构和润湿性变化相关.     

丁腈橡胶紫外线臭氧照射亲水改性及其水润滑性能研究

以丁腈橡胶为基底，采用紫外线-臭氧照射进行亲水/超亲水表面改性，通过接触角测量仪、光学显微镜对亲水改性表面的接触角、接触角滞后和微观形貌等特性进行表征，分析了表面亲水性的改性机理，并采用MFT-5000型摩擦磨损试验机测试了丁腈橡胶亲水表面的机械耐久性和保持性. 研究结果表明:采用紫外线臭氧照射丁腈橡胶10 min，就能得到完全润湿的超亲水表面，且在紫外线臭氧照射下，丁腈橡胶与臭氧发生反应生成氧化膜，使亲水改性后的丁腈橡胶，在干摩擦和水润滑状态下均表现出较小的摩擦系数和较好的耐磨性      

Permanent Alteration of Porous Media Wettability from Liquid-Wetting to Intermediate Gas-Wetting

Wettability of Berea and low permeability reservoir rocks are permanently altered from liquid-wetting to intermediate gas-wetting. We use water and decane as model liquid, and air and nitrogen as model gas in the experiments. New chemicals with various functional groups are used in the wettability alteration. We perform compositional analyses of the treated chemical solutions extracted from rock treatment by gas chromatography–mass spectrometry (GCMS) and by inductively coupled plasma-mass spectrometry (ICPMS). The analyses demonstrate reaction between the chemicals and the rock substrate. There is no measurable change in permeability from the chemical reaction for the low molecular weight chemicals. The results reveal the permanent alteration of wettability. Tests are conducted to measure contact angle, spontaneous imbibition, and flow to assess the effect of wettability alteration on flow performance as a function of chemical concentration and functionality. For Berea, the contact angle for the water–air–rock is altered from 0° to ~150° depending on the chemical concentration. For the reservoir rock, the contact angle is altered from ~70° to ~130°. As a result of the treatment, the water flow rate may increase two and a half times for a given pressure drop in the Berea. The permanent alteration of wettability with the new chemicals is intended for prevention of water blocking in gas production from tight reservoirs. Instead of hydraulic fracturing when water is introduced in formations with most of the water retained by the water-wet rocks, one may use the new chemical surfactants in fracturing to avoid water retention for high gas well productivity.     

二甲基—γ—全氟辛酰氧丙基硅烷自组装膜的制备及其摩擦学性能研究

利用分子自组装技术 ,用含有全氟烷基的氯硅烷作为前驱体 ,在活化玻璃表面制备了二甲基 -γ-全氟辛酰氧丙基硅烷单分子膜 ;用 X射线光电子能谱仪对组装膜表面的几种特征元素及其化学环境进行了表征 ;采用接触角测定仪测定了蒸馏水在自组装薄膜表面的接触角 ,在动静摩擦磨损试验机上评价了薄膜同 GCr1 5钢球对摩时的摩擦磨损性能 .结果表明 :所制备的自组装膜的表面自由能很低 ,具有很好的疏水 -疏油性 ,其对水的接触角高达 1 1 0°;二甲基 -γ-全氟辛酰氧丙基硅烷组装膜可以降低基片的摩擦系数 ,而且在较低负荷下具有很好的耐磨性     

Equilibrium shapes of strained islands with non-zero contact angles

The equilibrium morphology of a strained island on an elastic substrate is determined. The island is assumed to partially wet the substrate (Volmer-Weber growth) and thus makes a non-zero contact angle with the surface. Both isotropic and anisotropic misfit strain are allowed. Two- and three-dimensional equilibrium island shapes are determined by using expressions for the elastic strain energy in the small-slope approximation. In this limit, the problem can be reduced to a singular integral-differential equation for the island thickness. We find that when there is a non-zero contact angle, all island shapes, for a given ratio of the elastic stress to surface energy, attain a form that is independent of the specific contact angle under an appropriate scaling. We show that for islands with non-zero contact angles, as the island volume increases, the shape approaches the geometry of a completely wetting island. But when the volume decreases, these islands approach a point while islands with a zero contact angle, approach a finite length line segment of zero volume. Multiple-hump equilibrium shapes are found. Single-humped islands are shown to have a lower chemical potential than multiple-humped islands, implying that they are the most stable. This conclusion is shown to be consistent with a stability analysis of the two-dimensional case. The effects of a tetragonal misfit strain on the three-dimensional island shape is investigated.     

Effects of oxidation and surface roughness on contact angle

Contact angle is known to be a parameter that effects boiling. This study was undertaken to measure contact angle of high and low surface tension fluids on copper and aluminum surfaces.Data were taken for polished, oxidized, and rough surfaces. A simple, yet fairly accurate method of measuring the static equilibrium contact angle of a solid/liquid interface is presented. The principles of a line light source and tilting plate were modified and then combined in the design of this apparatus. The angles obtained and their variation with the solid surface properties were in good agreement with previously published data. The contact angle of distilled water o of the organic fluids and refrigerants tested were in the range of 2–5°. Roughness and oxidation reduce the contact angle. If the depth of the roughness is less than 0.5 μm contact angle. The apparatus is fairly simple in construction, is inexpensive, and has good reproductibity. The measured angles were then compared to those measured with the sessile drop method.