The tribological chemistry of the triazine derivative additives in rape seed oil and synthetic diester

The additives, laurylamino-methylthio-1,3,5-triazine-2,4-dithiol (referred to as TRLA) and diisooctylamino-methylthio-1,3,5-triazine-2,4-dithiol (referred to as TREA), were prepared in our laboratory. The products were characterized by means of infrared spectroscopy (IR) and elemental analysis. Their tribological behaviors as additives in raped seed oil and diester were evaluated using four-ball friction and wear testers as well. The results suggest that all the synthesized compounds have excellent tribological behaviors and they were compared with sulfurized isobutene (referred to as SIB) which is a commercial additive. The results show that they have good tribological properties. The two additives were investigated on thermal films and tribofilms by using X-ray absorption near edge structure (XANES) spectroscopy. The results of surface analysis reveal that the thermal films formed from TREA and TRLA in rape seed oil (referred to as RSO) and diester (referred to as DE), all are consist of iron sulfate; under mild AW conditions, the tribofilms from TRLA and TREA in DE is mainly composed of FeS, while the tribochemcal film from TRLA in RSO is mainly composed of iron sulfite; under EP-1 (the maximum non-seizure load) conditions, the tribochemical films from TRLA and TREA in RSO and DE mainly consist of FeS and FeSO₄; under EP-2 (nearly weld load) conditions, the tribochemical films from TRLA and TREA in RSO and DE mainly consist of FeS.     

Surface property enhancement by RE-borosulphurizing on high-carbon steel

Pack boronizing and rare-earth (RE)-borosulphurizing of high-carbon steel (T8) were conducted at 950 ^°C for 6 h. Characterizations of the layers formed on the surface of the high carbon steel were carried out by metallographic techniques, scanning electron microscopy, Auger electron spectroscopy and wear and corrosion resistance tests. It has been revealed that the diffusion front of the boride layer (BL) has a sawtooth shape, while that of the RE-borosulfide layer (RBSL) is flat. Different from the BL layer, the RBSL layer is compact, continuous and flat. The formation of FeS, Fe₂B and FeB phases on the substrates was confirmed by Auger electron spectroscopy analysis. The wear resistance test indicated that within a certain range, the abrasion resistance of the RBSL layer is better than that of the BL layer, especially under high-load conditions. The corrosion resistance test using the weight loss method has shown that the corrosion resistance of the RBSL layer is better but decreases faster with time extension than that of the BL layer.     

（Ti,Al）N Film on Normalized T8 Carbon Tool Steel Prepared by Pulsed High Energy Density Plasma Technique

Under optimized operating parameters, a hard and wear resistant （Ti,Al）N film is prepared on a normalized T8 carbon tool steel substrate by using pulsed high energy density plasma technique. Microstructure and composition of the film are analysed by x-ray diffraction, x-ray photoelectron spectroscopy, Auger electron spectroscopy and scanning electron microscopy. Hardness profile and tribological properties of the film are tested with nano- indenter and ring-on-ring wear tester, respectively. The tested results show that the microstructure of the film is dense ahd uniform and is mainly composed of （Ti,Al）N and A1N hard phases. A wide transition interface exists between the film and the normalized T8 carbon tool steel substrate. Thickness of the film is about lO00nm and mean hardness value of the film is about 26 GPa. Under dry sliding wear test conditions, relative wear resistance of the （Ti, Al）N film is approximately 9 times higher than that of the hardened T8 carbon tool steel reference sample. Meanwhile, the （Ti,Al）N film has low and stable friction coefficient compared with the hardened T8 carbon tool steel reference sample.     

Mild corrosion behavior on sulphurized steel surface during friction

After treatment by low temperature ion sulphuration, the solid lubrication sulphuration layers (FeS films) were produced on the AISI 1045 and stainless steel. A mass of corrosion peeling pits occurred on the worn scars of 1045 steel sulphuration layer after wear test, whereas none of them on the stainless steel one. AFM was used to observe the morphology of sulphuration layer, SEM equipped EDS was utilized to analyze the morphologies and compositions of worn scars. XPS and XRD were employed to detect the valence states of sulphuration layer and its worn scars, as well as the phase structures. The results showed that during friction, under the frictional heat, the sulfate radical with mild corrosion was produced, so that the 1045 steel without any anti-corrosion was corroded in some certain, meanwhile the stainless steel was not corroded depending on its excellent corrosion resistance.     

脉冲高能量密度等离子体法制备TiN薄膜及其摩擦磨损性能研究

利用脉冲高能量密度等离子体技术在室温条件下在45号钢基材上制备出了超硬耐磨TiN薄膜.利用XRD，XPS，AES，SEM等手段分析了薄膜的成分及显微组织结构，并测试了薄膜的硬度分布及摩擦磨损性能.结果表明：薄膜主要组成相为TiN，薄膜组织致密、均匀，与基材之间存在较宽的混合界面；薄膜硬度高，在干滑动磨损实验条件下具有优异的耐磨性及较低的摩擦系数. 关键词： 脉冲高能量密度等离子体 TiN膜 显微组织 耐磨性     

硫化廿二酸中氧与硫在菜籽油中的协同减摩抗磨作用研究

采用低温硫化工艺和复分解反应制备了无臭硫化廿二酸,在四球摩擦磨损试验机上考察了其在菜籽油中的减摩抗磨行为及承载能力,并对钢球磨损表面进行了扫描电子显微（ＳＥＭ）、电子探针（ＥＰＭＡ）以及Ｘ射线光电子能谱（ＸＰＳ）分析。通过与廿二酸和硫化异丁烯的对比研究发现,在廿二酸中引入硫后,氧与硫产生了明显的协同减摩抗磨及承载作用。钢球磨损表面ＸＰＳ分析结果表明,在摩擦过程中硫化廿二酸发生了摩擦化学变化,表面Ｅ     

Tribological behaviors of lanthanum-based phosphonate 3-aminopropyltriethoxysilane self-assembled films

Lanthanum-based thin films deposited on the phosphonate 3-aminopropyltriethoxysilane (APTES) self-assembled monolayer (SAM) were prepared on the hydroxylated glass substrate by a self-assembling process from specially formulated solution. Chemical compositions of the films and chemical state of the elements were detected by X-ray photoelectron spectrometry (XPS). The thickness of the films was determined with an ellipsometer, while the morphologies of the original and worn surfaces of the samples were analyzed by means of atomic force microscopy (AFM) and scanning electron microscopy (SEM), respectively. The tribological properties of the films sliding against GCr15 steel ball were evaluated on a UMT-2MT reciprocating friction and wear tester. As the results, the target film was obtained and reaction may have taken place between the film and the glass substrate. The tribological results show that lanthanum-based thin films are superior in reducing friction and resisting wear compared with APTES-SAM and phosphorylated APTES-SAM. SEM observation of the morphologies of worn surfaces indicates that the wear of APTES-SAM and the phosphorylated APTES-SAM is characteristic of brittle fracture and severe abrasion. Differently, slight abrasion and micro-crack dominate the wear of lanthanum-based thin films. The superior friction reduction and wear resistance of lanthanum-based thin films are attributed to the enhanced load-carrying capacity of the inorganic lanthanum particles in the lanthanum-based thin films as well as good adhesion of the films to the substrate.     

强流脉冲离子束辐照对电弧离子镀TiNbN硬质薄膜摩擦磨损性能的影响

 利用分离靶电弧离子镀工艺在高速钢基体上制备TiNbN多元硬质薄膜,利用TEMP-6型强流脉冲离子束（HIPIB）设备,采用含C/H离子、加速电压300 kV、脉冲宽度70 ns、束流密度60 A/cm2的强流脉冲离子束对所制备的薄膜进行辐照处理,研究辐照前后膜层的摩擦磨损性能的变化。实验结果表明：HIPIB辐照以后,薄膜的表面熔化,摩擦系数降低,晶粒细化,膜层的硬度由HK3444提高到HK3820,膜基结合力由59 N提高到65 N。在测试载荷300 N和600 N条件下,薄膜的摩擦磨损性能均有较大改善。     

Molecular Beam Epitaxy Growth of Tetragonal FeS Films on SrTiO_3(001) Substrates

We report the successful growth of the tetragonal FeS film with one or two unit-cell(UC) thickness on SrTiO_3(001)substrates by molecular beam epitaxy. Large lattice constant mismatch with the substrate leads to high density of defects in single-UC FeS, while it has been significantly reduced in the double-UC thick film due to the lattice relaxation. The scanning tunneling spectra on the surface of the FeS thin film reveal the electronic doping effect of single-UC FeS from the substrate. In addition,at the Fermi level,the energy gaps of approximately 1.5 meV are observed in the films of both thicknesses at 4.6 K and below. The absence of coherence peaks of gap spectra may be related to the preformed Cooper-pairs without phase cOherence.     

Structure and topography modifications of austenitic steel surfaces after friction in sliding contact

Friction experiments between two austenitic stainless steel (AISI 304L) surfaces in sliding contact were carried out under very low loads in two liquid environments, namely demineralized water and methanol, in order to study the correlation between surface damage (wear and surface topography) and structural modifications (phase formation and microstructure). The particularity of our approach was to perform the tests under Hertzian pressures, which were several orders of magnitude lower than the elastic limit of stainless steel. The structural modifications produced during friction were analysed by X-ray diffraction and transmission electron microscopy and the surface topography was studied by scanning electron microscopy and three-dimensional (3D) profiling. Whatever the experimental conditions investigated, the morphology of the damage observed on both surfaces consisted of very fine, smooth and parallel grooves typical of an abrasive wear process of a ductile material caused by the ploughing action of hard particles. From the beginning of the tests, the transformation of austenite into martensite was observed in the superficial layers and the dominant presence of martensite was identified in the wear debris. These results suggest that, under our experimental conditions, abrasion is the dominant mechanism of material removal. Received: 12 March 2002 / Accepted: 3 May 2002 / Published online: 10 September 2002 RID="*" ID="*"Corresponding author. Fax: +33-5/4949-6692, E-mail: jean.paul.riviere@univ-poitiers.fr     

Mechanical properties of Ti(C0.7N0.3) film produced by plasma electrolytic carbonitriding of Ti6Al4V alloy

Porous nanocrystalline Ti(C_0.7N_0.3) film on Ti6Al4V substrate was prepared by plasma electrolytic carbonitriding (PECN). The film was characterized and analyzed by using a variety of analytical techniques, such as XRD, SEM, EDX, TEM, FESEM, Rockwell C indenter, scratch tester, Vickers microhardness tester and ring-on-block tribometer. The results showed that the film was about 15 μm thick and its hardness was Hv 2369 at a load of 0.2 N. The adhesion of the film was characterized by Lc and Pc value, and was found to be about 42 N and more than 800 N, respectively. The friction coefficients and wear volume loss of the PECN-treated samples sliding against a steel counterpart were much less than those of the untreated Ti6Al4V. The film possessed a good wear-resistance and antifriction under oil-lubricated condition due to its high hardness, adhesion and fracture toughness. Also, the porous surface morphology of the Ti(C_0.7N_0.3) film contributed to the enhanced tribological resistance by promoting the formation of lubricant film and entrapping wear debris.     

拉曼光谱研究天然FeS_2晶须结构及其相变规律

利用显微激光拉曼技术研究了山西耿庄天然纳-微米FeS2晶须的结构.发现FeS2晶须中有白铁矿和黄铁矿两种结构类型.较粗的藕节状、粗柱状、串珠状等不规则形貌为白铁矿相,直线状、平直、表面光滑的品须为黄铁矿相.耿庄FeS2晶须结晶生长早期以白铁矿相为主,中期是白铁矿和黄铁矿型结构共存,晚期以黄铁矿相为主.晶须生长过程有早期白铁矿结晶向晚期黄铁矿结晶转变的趋势.而且有黄铁矿包覆白铁矿的生长现象.FeS2晶须结构相变规律与形貌、形成时间和成分特点具有关联性.     

铁基合金激光熔覆层高温润滑磨损性能

 为提高40Cr合金钢的表面耐磨性,采用预置激光熔覆法在40Cr基体表面制备铁基合金涂层, 利用扫描电镜观察分析熔覆层显微组织形貌,用显微硬度仪测试熔覆层截面显微硬度,用摩擦磨损试验机测定在润滑条件下基体、熔覆层的摩擦系数随温度变化的规律。研究结果表明:熔覆层与基体实现良好冶金结合,熔覆层横截面微观组织呈现平面晶、树枝晶和胞状晶分布;熔覆层硬度值介于617.5~926.6 HV0.2之间,基体硬度介于205.2~278.2 HV0.2之间;在200 ℃以下,熔覆层摩擦系数在磨程中趋于平稳,在0.1附近轻微波动,小于基体平均摩擦系数;当温度超过200 ℃,油膜分解,引发润滑失效,磨损方式向干摩擦转化,磨损机理从微切削磨损主导向粘着磨损、磨粒磨损和氧化磨损复合磨损方式转化。     

Friction and wear of rare earths modified carbon fibers filled PTFE composite under dry sliding condition

Carbon fibers (CF) were surface treated with air-oxidation and rare earths (RE), respectively. The friction and wear properties of polytetrafluoroethylene (PTFE) composites filled with differently surface treated carbon fibers, sliding against GCr15 steel under dry sliding condition, were investigated on a block-on-ring M-2000 tribometer. Experimental results revealed that RE treatment largely reduced the friction and wear of CF reinforced PTFE (CF/PTFE) composites. The RE treated composite exhibited the lowest friction and wear under dry sliding. Scanning electron microscopy (SEM) investigation of worn surfaces and transfer films of CF/PTFE composites showed that RE treated CF/PTFE composites had the smoothest worn surface under given load and sliding speed, and a continuous and uniform transfer film formed on the counterface. X-ray photoelectron spectroscopy (XPS) study of carbon fiber surface showed that the oxygen concentration was obviously increased after RE treatment, and more carboxyl groups were introduced onto CF surfaces after RE treatment. The increase in the amount of oxygen-containing groups increased the interfacial adhesion between CF and PTFE matrix, and accordingly increased the tribological properties of the composite.     

Influence of the Interfacial Characteristics on the Tribological Behaviour of TiN-Base Films on Iron

The dry sliding behaviour of TiN-base films deposited onto a tool steel by two different physical vapour deposition techniques is discussed on the basis of the characteristics of both coatings and interfacial regions. It is shown that film adhesion is determining for the wear resistance. Other important factors are the film hardness and the intensity of the stress state at the film-substrate interface.     

Nanoscratch studies of SiGe epitaxial layer damage on the Si substrate

The present study evaluates the wear performance of silicon-germanium (SiGe) epitaxial growth of thin films, in which the in situ scratch profile is followed by ex situ atomic force microscopy (AFM) examinations. The wear evaluation of SiGe films was carried out at different constant loads (2000, 4000, and 6000 μN) with the same sliding speeds. The microstructural morphology was observed by means of transmission electron microscopy (TEM)Findings show that annealing treatments of SiGe films exhibit the highest scratch resistance at 400 °C compared to that of the as-deposited sample. The main characteristic of SiGe film is its ability to withstand wear resistance; observations show that moderate compressive residual is beneficial to the film, since it can suppress crack initiation. The annealing treatments of SiGe films revealed the resultant adhesive and cohesive failure mechanism.     

电镀法在氧化铟锡上制备铜锌锡硫薄膜的光谱特征

低成本、环境友好的铜锌锡硫替代含贵金属和有毒金属的铜铟镓硒,是薄膜太阳能电池的最佳选择。电镀法是一种无需真空设备和靶材的低成本方法。一种更简单的制膜方法是在水溶液中共电镀沉积Cu-Zn-Sn（CZT)合金于FTO衬底上。采用氩气保护气氛下在550 ℃硫化电镀法制得的CZT合金前驱体,成功制备了CZTS薄膜。采用三电极体系将CZT合金前驱体电镀在FTO上,其中FTO作为工作电极,铂（Pt）网和Ag/AgCl分别作为对电极和参比电极。电解质由CuSO₄,ZnSO₄,SnSO₄,络合剂-三乙醇胺（TEA）和柠檬酸钠组成。前驱体在氩气保护气氛下550℃硫化得到CZTS薄膜。采用X射线衍射（XRD）、拉曼光谱、扫描电子显微镜（SEM）、紫外可见光光谱仪和光电化学测量（PEC）等方法,表征了CZTS薄膜的结构、形貌、成分和光谱学性质。XRD和拉曼光谱证明了550 ℃硫化后的CZTS薄膜具有锌黄锡矿结构。一个Raman主峰位于342 cm-1,两个Raman次强峰分别位于289和370 cm-1,这些峰位与锌黄锡矿CZTS的峰位相吻合。SEM结果证明优化后CZTS薄膜成分接近CZTS的理想化学计量比,CZTS薄膜中Cu/(Zn+Sn）和 S/(Zn+Sn+Cu)分别为0.52和1.01,这表明CZTS薄膜中S的含量非常合适。PEC结果证实,采用前照射或后照射FTO/CZTS均产生光电流,并且两种照射下产生的光电流方向一致。通过紫外可见光光谱测量并由此计算出的CZTS能隙为1.45 eV。通过上述分析证明制备的CZTS薄膜具有高品质,可用于制备CZTS薄膜太阳能电池。     

Tribological behaviors of self-assembled 3-aminopropyltriethoxysilane films on silicon

3-Aminopropyltriethoxysilane (APTES) thin films were prepared on the hydroxylated silicon substrate by a self-assembling process from formulated solution. Chemical compositions of the films were detected by X-ray photoelectron spectrometry (XPS). The thickness of the films was determined with an ellipsometer, while the morphologies of the original and worn surfaces of the samples were analyzed by means of atomic force microscopy (AFM) and scanning electron microscopy (SEM), respectively. The tribological properties of APTES thin films sliding against GCr15 steel ball were evaluated on a UMT-2MT reciprocating friction and wear tester. It was found that the macroscopic friction coefficients for coating times more than 1 h ranged from 0.177 to 0.3 whereas the value for short coating time was as high as 0.8. It was also found that the tribological behaviors of APTES films were sensitive to normal load and sliding velocity. SEM observation of the morphologies of worn surfaces indicates that the wear of silicon is characteristic of brittle fracture and severe abrasion. Differently, abrasion and micro-crack dominate the wear of APTES–SAM. The superior friction reduction and wear resistance of APTES films compared to the silicon substrate are attributed to good adhesion of the films to the substrate.     

Friction,adhesion and wear durability of an ultra-thin perfluoropolyether-coated 3-glycidoxypropyltrimethoxy silane self-assembled monolayer on a Si surface

The tribological properties, such as coefficient of friction, adhesion and wear durability of an ultra-thin (<10?nm) dual-layer film on a silicon surface were investigated. The dual-layer film was prepared by dip-coating perfluoropolyether (PFPE), a liquid polymer lubricant, as the top layer onto a 3-glycidoxypropyltrimethoxy silane self-assembled monolayer (epoxy SAM)-coated Si substrate. PFPE contains hydroxyl groups at both ends of its backbone chain, while the SAM surface contains epoxy groups, which terminate at the surface. A combination of tests involving contact angle measurements, ellipsometry, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) was used to study the physical and chemical properties of the film. The coefficient of friction and wear durability of the film were investigated using a ball-on-disk tribometer (4?mm diameter Si₃N₄ ball as the counterface at a nominal contact pressure of ～330?MPa). AFM was used to investigate the adhesion forces between a sharp Si₃N₄ tip and the film. This dual-layer film had a very low coefficient of friction, adhesion and wear when compared to epoxy SAM-coated Si only or bare Si surface. The reasons for the improved tribological performance are explained in terms of the lubrication characteristics of PFPE molecules, low surface energy of PFPE, covalent bonding between PFPE and epoxy SAM coupled with reduced mobile PFPE. The low adhesion forces coupled with high wear durability show that the film has applications as a wear resistant and anti-stiction film for microcomponents made from Si.     

Femtosecond laser-induced periodic surface structures on steel and titanium alloy for tribological applications

Laser-induced periodic surface structures (LIPSS, ripples) were generated on stainless steel (100Cr6) and titanium alloy (Ti6Al4V) surfaces upon irradiation with multiple femtosecond laser pulses (pulse duration 30 fs, central wavelength 790 nm). The experimental conditions (laser fluence, spatial spot overlap) were optimized in a sample-scanning geometry for the processing of large surface areas (5 × 5 mm²) covered homogeneously by the nanostructures. The irradiated surface regions were subjected to white light interference microscopy and scanning electron microscopy revealing spatial periods around 600 nm. The tribological performance of the nanostructured surface was characterized by reciprocal sliding against a ball of hardened steel in paraffin oil and in commercial engine oil as lubricants, followed by subsequent inspection of the wear tracks. For specific conditions, on the titanium alloy a significant reduction of the friction coefficient by a factor of more than two was observed on the laser-irradiated (LIPSS-covered) surface when compared to the non-irradiated one, indicating the potential benefit of laser surface structuring for tribological applications.