Thermal Error Compensation of the Wear-Depth Real-Time Detecting of Self-Lubricating Spherical Plain Bearings

The spherical plain bearing test bench is a necessary detecting equipment in the research process of self?lubricating spherical plain bearings. The varying environmental temperatures cause the thermal deformation of the wear?depth detecting system of bearing test benches and then a ect the accuracy of the wear?depth detecting data. However, few researches about the spherical plain bearing test benches can be found with the implementation of the detect?ing error compensation. Based on the self?made modular spherical plain bearing test bench, two main causes of ther?mal errors, the friction heat of bearings and the environmental temperature variation, are analysed. The thermal errors caused by the friction heat of bearings are calculated, and the thermal deformation of the wear?depth detecting sys?tem caused by the varying environmental temperatures is detected. In view of the above results, the environmental temperature variation is the main cause of the two error factors. When the environmental temperatures rise is 10.3 °C, the thermal deformation is approximately 0.01 mm. In addition, the comprehensive compensating model of the thermal error of the wear?depth detecting system is built by multiple linear regression(MLR) and time series analysis. Compared with the detecting data of the thermal errors, the comprehensive compensating model has higher fitting precision, and the maximum residual is only 1 μm. A comprehensive compensating model of the thermal error of the wear?depth detecting system is proposed, which provides a theoretical basis for the improvement of the real?time wear?depth detecting precision of the spherical plain bearing test bench.

Microstructure and properties of HVOF sprayed Ni-based submicron WS_2/CaF_2 self-lubricating composite coating

Ni-based submicron WS2/CaF2 self-lubricating composite coatings were produced on carbon steel substrate by high velocity oxygen fuel(HVOF) spray processing, and the microstructure and mechanical properties of the coatings were investigated. Non-uniform microstructure characterized by some pores and microcracks is observed in the produced composite coatings, which leads to low microhardness value, low adhesive strength and low frictional coefficient. For Ni45-5%CaF2-10%WS2 (mass fraction) and Ni45-10%CaF2-5%WS2 (mass fraction) coatings, under the test condition of load 40 N and speed 2 m/s, the friction coefficients obtained at room temperature are in the range of 0.35-0.48 and 0.31-0.41, respectively. The friction coefficients of two kinds of coatings increase to 0.4-0.63 and 0.35-0.46, respectively, at the test speed of 1 m/s. And the Ni45-10%CaF2-5%WS2 coating presents the minimum friction coefficient of 0.32-0.38 and good anti-wear properties at 400 ℃.

The Friction and Wear Properties of the Spherical Plain Bearings with Self-lubricating Composite Liner in Oscillatory Movement

A test method based on the condition simulation and a friction and wear test machine featuring in oscillatory movement were set up for self-lubricating spherical plain bearings (SPB). In the machine the condition parameters such as load, angle and frequency of oscillation and number of test cycles can be properly controlled. The data relating to the tribological properties of the bearing, in terms of friction coefficient, linear wear amount, temperature near friction surface and applied load, can be monitored and recorded simultaneously during test process by a computerized measuring system of the machine. Efforts were made to improve the measurement technology of the friction coefficient in oscillating motion. In result, a well-designed bearing torque mechanism was developed, which could reveal the relation between the friction coefficient and the displacement of oscillating angle in any defined cycle while the curve of friction coefficient vs number of testing cycles was continuously plotted. The tribological properties and service life of four kinds of the bearings, i.e, the sampleⅠ-Ⅳ with different self-lubricating composite liners, including three kinds of polytetrafluoroethylene (PTFE) fiber weave/epoxy resin composite liners and a PTFE plastic/copper grid composite liner, were evaluated by testing, and the wear mechanisms of the liner materials were analyzed.

Effects of Friction Heat on the Tribological Properties of the Woven Self-lubricating Liner

In the dry-sliding process of the woven self-lubricating liner which is used in the self-lubricating spherical plain bearing, the friction heat plays an important role in the tribological performances of the liner. It has important value to study on the relationship between tribological performances of the liner and the friction heat. Unforttmately, up to now, published work on this relationship is quite scarce. Therefore, the effect of friction heat on the tribological performances of the liner was investigated in the present work. The tribological behaviors of the liner were evaluated by using the high temperature end surface wear tester. Scanning electron microscopy （SEM） was utilized to examine the morphologies of worn surfaces of the liner and study the failure modes. Differential scanning calorimetry （DSC） measurement and X-ray diffraction （XRD） analysis were performed to study the behaviors of the wear debris. The temperature rise on the worn surface was calculated according to classical models. SEM observation shows that the dominating wear mechanism for the liner is mainly affected by friction shear force, contact pressure and friction heat. Higher fusion heat for the wear debris than that for the pure polytetrafluroethylene （PTFE） indicates that the PTFE is the main portion of the wear debris, and, the PTFE in the wear debris shows a higher crystallisation degree owing to the effects of friction shear force and the friction heat. Combining the calculated temperature rise results with the wear rate of the liner, it can be concluded that the effects of temperature rise o n the tribological performances of the liner become more obvious when the temperature rise exceeds the glass transition temperature （Tg） of the PTFE. The wear resistance of the liner deteriorates dramatically when the temperature rise approaches to the melting point （Ton） of the PTFE. The tribological performances of the liner can be improved when the temperature rise exceeds Tg but is far lower than Ton- The present study on the relationship between the temperature rise and the tribological performances of the liner may provide the basis for further understanding of the wear mechanisms of the liner as well as the relationship between the formation of the PTFE transfer film and the friction heat during the dry-sliding of the Finer.

Mechanical and friction properties of aluminum and titanium reinforced Ni-based self-lubricating composite

Ni-20Cr powders mixed with tungsten,aluminum,titanium,and different contents of molybdenum disulfides were hot-pressed in graphite mould by powder metallurgy method. Their tribological properties from room temperature to 600 ℃ and mechanical properties at atmosphere were tested. The results show that the hardness and anti-bending strength of composites increase by more than 20% when containing 6%(mass fraction) MoS2. But when molybdenum disulfide content exceeds 6%,the hardness and anti-bending strength will decrease gradually. The addition of MoS2 is favored to the reduction of friction coefficient of composite. The friction coefficient of composite decreases with the increase of molybdenum disulfide until the percentage of lubricant reaches 12%. In excess of this value,the friction coefficient value starts to ascend. The wear rates of composite with molybdenum disulfide are one order of magnitude lower than the alloy without lubricant. When the addition amount of MoS2 is in the range of 6% and 12%,the wear rates keep at the resemble level.

Study on Solid Self-Lubricating Material for Plasma Facing Components in EAST

In this study, the friction performance of self-lubricating material with the counterpart steel ball-plate rubbing was investigated in vacuum conditions and the thermal distortion of the heat sink sample was tested. The analysis and test results show that the self-lubricating ma- terial has excellent anti-friction properties in high vacuum condition and can decrease the thermal stress and avoid damage to the PFCs during physical experiments.

Tribological Behavior of Ni-based Self-lubricating Composites with the Addition of Ti3SiC2 and Ag2W2O7

The tribological properties of Nickel-based composites containing Ti3 SiC2 and Ag2 W2 O7 fabricated by spark plasma sintering against Si3 N4 balls were investigated using a ball-on-disk tribometer from room temperature to 600 ℃. The tribolayers formed on the friction surface and their effects on the tribological properties of composites at different temperatures were discussed based on the worn surface characterization. The results show that Ag2 W2 O7 is decomposed into metallic silver and CrWO4 during the high-temperature fabrication process. The composite with the addition of 20 wt% Ti3 SiC2 and 5 wt% Ag2 W2 O7 exhibits a friction coefficient of 0.33-0.49 and a wear rate of 7.07×10-5-9.89×10-5 mm3/（Nm） over a wide temperature range from room temperature to 600 ℃. The excellent tribological properties at a wide temperature range are attributed to the formation of a glaze layer at low temperature and a tribooxide layer at high temperature, which can provide a low shearing strength for the synergistic effects of Ag and tribooxides.

Tribological Properties of Self-lubricating Laminated Ceramic Materials

In order to improve the tribological properties of ceramic composites, Al2O3/TiC-Al2O3/ TiC/CaF2 self-lubricating laminated ceramic composites were prepared by vacuum hot pressing sintering. Experiments were conducted to get mechanical properties and the friction and wear properties were also measured with friction and wear tester. The worn surfaces were observed by scanning electron microscope （SEM） and energy dispersion spectrum （EDS）. The wear resistance properties and the self-lubricating effect of ceramic composites were analyzed. Results show that the Al2O3/TiC-Al2O3/TiC/CaF2 self-lubricating laminated ceramic composites layers are well-defined with a higher bonding strength and the mechanical performances are uniform enough to overcome the anisotropy of weak laminated ceramic composites. In addition, the fracture toughness of Al2O3/TiC layers is also improved. Its friction coefficient and wear rates decrease with the increase of rotation speed and load. Al2O3/TiC-Al2O3/TiC/CaF2 self-lubricating laminated ceramic composites have good wear resistance because of the tribofilm formed by the CaF2 solid lubricants. The wear mechanisms of Al2O3/TiC/ CaF2 layers are abrasive wear and Al2O3/TiC layers are adhesive wear.

MoSe_(2)/石墨烯-不锈钢自润滑材料的减摩机理

为克服不锈钢摩擦副零件摩擦因数大、易磨损的不足,利用粉末冶金不锈钢基体贯通孔隙特征和异质结纳米润滑剂超滑效应,采用真空浸渍和水热合成两步法工艺制备出了MoSe_(2)/石墨烯-不锈钢自润滑材料,并对其摩擦学特性与减摩机理进行了研究。研究发现:摩擦过程中,加入到基体孔隙的MoSe_(2)/石墨烯异质结润滑剂在摩擦表面形成了均匀润滑膜,显著减小了摩擦副的摩擦因数和磨损率。在常温、载荷40 N、转速100 r/min工况下,MoSe_(2)/石墨烯-不锈钢自润滑材料的摩擦因数低至0.106,磨损率降至6.45×10^(-5)mm^(3)/(N·m),与不锈钢基体相比,其摩擦因数和磨损率分别降低了86%和93%。

SLM铝合金表面喷射电沉积Ni-MoS_(2)自润滑复合涂层

采用喷射电沉积在SLM铝合金表面制备Ni-MoS_(2)自润滑复合涂层。用摩擦磨损试验机评价镀液中MoS_(2)浓度对Ni-MoS_(2)自润滑复合涂层摩擦磨损性能的影响。结果表明:共沉积MoS_(2)微粒能有效降低Ni-MoS_(2)自润滑复合涂层的摩擦系数和磨损率。与纯Ni涂层相比,Ni-MoS_(2)自润滑复合涂层与316L钢球对磨的摩擦系数和磨损率显著降低,摩擦系数从0.51降至0.12,磨损率从0.41 mg/m降至0.11 mg/m,为SLM铝合金表面改善摩擦学性能提供了参考。

等离子喷涂NiCrAl/Cr_(2)O_(3)/V_(2)O_(5)-Bi_(2)O_(3)复合涂层的制备及其高温摩擦行为研究

采用等离子喷涂制备了NiCrAl/Cr_(2)O_(3)/V_(2)O_(5)-Bi_(2)O_(3)复合涂层,并对涂层在600℃下的摩擦学行为进行了研究.结果表明:通过共混球磨、粘接团聚的方法,可制备出微米级且具有较好团聚形貌的V_(2)O_(3)-Bi_(2)O_(3)复合粉体,能够作为Ni基复合涂层的等离子喷涂喂料.复合涂层在600℃的平均摩擦系数为0.33,且得益于良好高温自润滑性能、以及添加Cr_(2)O_(3)能够缓解V_(2)O_(5)-Bi_(2)O_(3)对涂层硬度的不利作用,因而复合涂层磨损率(3.84×10^(-4)mm^(3)/N·m)约为纯NiCrAlY涂层的一半.在高温摩擦下,复合涂层磨痕内生成以BiVO4为主的多元氧化物摩擦化学产物,并表现出易剪切滑移特征,这是复合涂层良好高温自润滑性的主要原因.

放电等离子烧结Cu-15Ni-8Sn/石墨自润滑复合材料摩擦磨损性能研究

以Cu-15Ni-8Sn合金为基体,石墨为润滑剂,采用放电等离子烧结技术制备了Cu-15Ni-8Sn/石墨自润滑复合材料.使用扫描电子显微镜、X射线衍射仪和万能试验机研究了复合材料的微观组织、物相组成和室温力学性能,通过球-盘式摩擦试验机测试复合材料的摩擦磨损性能,利用三维轮廓仪测量材料磨损体积,借助扫描电子显微镜对磨痕形貌进行表征.结果表明:向Cu-15Ni-8Sn基体材料中添加石墨后,材料的硬度明显降低;随着石墨含量的提高,复合材料的抗压强度逐渐降低.当添加质量分数为3%的石墨时,Cu-15Ni-8Sn/石墨自润滑复合材料的耐磨性最好,磨损率最小为3.0×10^(-6)mm^(3)/(N·m),其磨损机理主要以磨粒磨损为主.

Effect of surface roughness on the surface lubrication performance of galvanized steel sheets with a self-lubricated coating

Four kinds of galvanized steel sheets having different surface roughness values were used to prepare the steel sheets with a self-lubricated coating. The effects of surface roughness on the surface lubrication performance of the steel sheets were examined using a friction coefficient tester. Results revealed large dynamic friction coefficients for the galvanized steel sheets, which increased remarkably with surface roughness. Once the self-lubricated coating was applied, significant drops in the dynamic friction coefficients were measured. After the first stage of the friction test,the coefficients were almost unchanged, which reflected a weak dependence on the surface roughness of the self-lubricated steel sheets. However, the dynamic friction coefficients gradually increased as the test progressed, where these increase clearly correlated with the surface roughness of the self-lubricated steel sheets.

磷酸锆对铜铋-钢背双层金属复合材料性能的影响

采用烧结压轧复合工艺制备了铜铋-钢背双层金属复合材料板材,研究了磷酸锆对铜铋-钢背复合材料板材结合强度、硬度及摩擦学性能的影响。结果表明:磷酸锆的添加可以有效改善铜铋-钢背复合材料板材减摩耐磨性能,并能够提升其抗承载能力。随着磷酸锆质量分数的增加,铜铋-钢背复合材料板材的结合强度逐渐减小,硬度先增大后减小。在定速定载寿命试验中,与未添加磷酸锆的铜铋-钢背复合材料板材相比,添加质量分数为2%和4%的磷酸锆可以有效改善铜铋-钢背复合材料板材的减摩耐磨性能,降低摩擦副摩擦系数,有利于表面温升。在定速变载荷试验中,磷酸锆的添加可以显著提升铜铋-钢背双层材料的摩擦抗承载能力。在端面油循环条件下,添加质量分数4%磷酸锆的铜铋-钢背复合材料板材极限PV值(摩擦副接触面压强与摩擦线速度乘积)可以达到14 MPa∙m∙s^(-1),而未添加磷酸锆的铜铋-钢背复合材料板材极限PV值仅8 MPa∙m∙s^(-1),提升约75%。

Self-lubricated Array Film of Amorphous Carbon Nanorods on an Aluminum Substrate

A self-lubricated array film of amorphous carbon nanorods was prepared by chemical catalytic pyrolysis of acetylene on the anodic aluminum oxide membrane fabricated by two-step anodization of aluminum. The tribological properties of the array film of amorphous carbon nanorods in ambient air were investigated using a ball-on-disk tester at applied loads range from 245 mN to 1960 mN at a sliding velocity of 0.2 m/s. The self-lubricated array film exhibited a small value of the friction coefficient as well as good wear resistance. The friction coefficient of array film of amorphous carbon nanorods decreased gradually with increasing the applied load. The approach proposed demonstrated a new efficient route towards enhanced the friction and wear performances of aluminum.

无机-有机杂化微胶囊:制备技术及在抗磨耐腐蚀涂层中的应用

微胶囊是增强涂层抗磨耐腐蚀性能的有效途径,对涂层抗磨耐腐蚀的研究有着重要意义。常见的微胶囊通常以聚砜(PSF)、聚脲甲醛(PUF)、聚三聚氰胺甲醛(PMF)、聚脲(PU)等有机物质为外壳,当与无机物质复合制成杂化壳时,能够显著增强微胶囊的耐温性、相容性,并有效调节其渗透性和机械强度。纳米粘土、纳米SiO_(2)、纳米CaCO_(3)、纳米Al_(2)O_(3)和碳纳米管等是合成杂化壳的良好材料。无机-有机杂化微胶囊具有强的耐温性、力学强度和物理稳定性。利用微胶囊包覆油性物质或离子液体,制备具有自润滑、自修复性能的涂料,在抗磨耐腐蚀方面有广泛应用。目前,无机-有机杂化微胶囊的制备方法主要有溶剂蒸发法、Pickering乳液法、原位聚合法和界面聚合法等。溶剂蒸发法试验周期短、简单易行。Pickering乳液法能有效提高包封效率。原位聚合法成球容易、包覆量大且无副产物。界面聚合法具有速度快、反应温和等优势。本文讨论了无机-有机杂化微胶囊的制备方法,简述了微胶囊的抗磨耐腐蚀机制,并以制备方法为分类依据,概述了微胶囊在增强高分子有机涂层相关性能中的具体运用,最后对无机-有机杂化微胶囊的制备与应用进行了展望,以期为微胶囊在更多领域中的运用提供参考。

Comparison of Microbubble and Air Layer Injection with Porous Media for Drag Reduction on a Self-propelled Barge Ship Model

Ship resistance issues are related to fuel economy,speed,and cost efficiency.Air lubrication is a promising technique for lowering hull frictional resistance as it is supposed to modify the energy in the turbulent boundary layer and thereby reduce hull friction.In this paper,the objective is to identify the optimum type of air lubrication using microbubble drag reduction(MBDR)and air layer drag reduction(ALDR)techniques to reduce the resistance of a 56-m Indonesian self-propelled barge(SPB).A model with the following dimensions was constructed:length L=2000 mm,breadth B=521.60 mm,and draft T=52.50 mm.The ship model was towed using standard towing tank experimental parameters.The speed was varied over the Froude number range 0.11–0.31.The air layer flow rate was varied at 80,85,and 90 standard liters per minute(SLPM)and the microbubble injection coefficient over the range 0.20–0.60.The results show that the ship model using the air layer had the highest drag reduction up to a maximum of 90%.Based on the characteristics of the SPB,which operates at low speed,the optimum air lubrication type to reduce resistance in this instance is ALDR.

Parameter Self - Learning of Generalized Predictive Control Using BP Neural Network

This paper describes the self—adjustment of some tuning-knobs of the generalized predictive controller(GPC).A three feedforward neural network was utilized to on line learn two key tuning-knobs of GPC,and BP algorithm was used for the training of the linking-weights of the neural network.Hence it gets rid of the difficulty of choosing these tuning-knobs manually and provides easier condition for the wide applications of GPC on industrial plants.Simulation results illustrated the effectiveness of the method.

Self - Crosslinking Behavior of Self - Emulsion Water - Based Polyure-thane Coating Agents

The relation between structures and properties of polyurethane are investigated by modern physical and chemical methods.The results obtained are as follows:the effects of the content of self-crosslinking agent on the properties of polyurethane,i.e.,dispersion stability,dynamical viscoelasticity and mechanical properties are discussed.It is found that the optimum molar ratio of epichlorohydrin and diethylenetriamine is 1:2.A mois-

Culture Self- Consciousness in Transmission of Chinese Philosophy from the Perspective of English Globalization -- Taking the Belt and Road Initiative for Example

The Belt and Road Initiative contains the aspiration of Chinese nation to pursue ideological freedom and desire of strengthening international exchanges and cooperation. This paper takes the Belt and Road Initiative for example,emphasizing the interpretation of the inheritance and development of Chinese culture so as to study the importance of Culture Self-Consciousness in Chinese Philosophy,in the context of English globalization. That is to say,this paper stresses the spirits and the stand of nation 's demonstration on pursuing peace,cooperation and sustainable development in the civilization continuity from traditional China to the contemporary China,with practical philosophic view.