清净剂、分散剂与ZDDP复配对a-C薄膜摩擦学性能的影响*

固-液复合润滑系统是获得高燃油经济性和高耐用性发动机系统的关键技术。极压抗磨剂二烷基二硫代磷酸锌（Zinc dialkyldithiophosphate, ZDDP）、清净剂高碱基磺酸钙（Over-base calcium sulfonate, OBCaSu）与分散剂聚异丁烯丁二酰亚胺 （Polyisobutylene succinimide, PIBSI）作为配方润滑油中使用最广泛的三种润滑油添加剂，与常用发动机表面强化薄膜类金刚石（Diamond-like carbon, DLC）薄膜复配下摩擦学性能的相关研究仍较少。利用非平衡磁控溅射方法制备 a-C 薄膜，通过 CSM 摩擦磨损试验机评价 ZDDP 与 OBCaSu（ZDDP+OBCaSu）、ZDDP 与 PIBSI（ZDDP+PIBSI）复配条件下 a-C 薄膜的摩擦学性能，并利用拉曼光谱、SEM 和 EDS 能谱等手段分析摩擦化学反应，探究摩擦机理。结果表明，ZDDP、ZDDP+OBCaSu 和 ZDDP+PIBSI 润滑三种润滑条件下，GCr15 钢和 a-C 薄膜磨损表面形成含磷酸盐的摩擦反应膜，两者摩擦学性能随润滑剂的变化规律相似。ZDDP+OBCaSu 复配润滑下，磨损表面形成的 Ca₃(PO₄)₂ 和 Zn₃(PO₄)₂ 复合摩擦反应膜可以提高 GCr15 钢和 a-C 薄膜的抗磨损性能。ZDDP+PIBSI 复配润滑下，GCr15 钢和 a-C 薄膜摩擦学性能下降。通过对比研究传统润滑油添加剂在 GCr15 钢和 a-C 薄膜表面的摩擦学行为和摩擦化学反应机理，为 a-C 薄膜在发动机系统中应用以及研发适配 a-C 薄膜的润滑油配方提供数据支持和理论指导。     

纳米生物润滑剂微量润滑磨削性能研究进展

微量润滑是针对浇注式和干磨削技术缺陷的理想替代方案，为了满足高温高压边界条件下磨削区抗磨减摩与强化换热需求，进行了纳米生物润滑剂作为微量润滑的雾化介质探索性研究。然而，由于纳米生物润滑剂的理化特性与磨削性能之间映射关系尚不清晰，纳米生物润滑剂作为冷却润滑介质在磨削中的应用仍然面临着严峻的挑战。为解决上述需求，本文基于摩擦学、传热学和工件表面完整性对纳米生物润滑剂的磨削性能进行综合性评估。首先，从基液和纳米添加相的角度阐述了纳米生物润滑剂的理化特性。其次，结合纳米生物润滑剂独特的成膜和传热能力，分析了纳米生物润滑剂优异的磨削性能。结果表明，纳米生物润滑剂优异的传热和极压成膜性能显著改善了磨削区的极端摩擦条件，相比于传统微量润滑，表面粗糙度值（Ra）可降低约10%～22.4%。进一步地，阐明了多场赋能调控策略下，磨削区纳米生物润滑剂浸润与热传递增效机制。最后，针对纳米生物润滑剂的工程和科学瓶颈提出了展望，为纳米生物润滑剂的工业应用和科学研究提供理论指导和技术支持。     

基于Deform复合润滑剂镦粗试验和摩擦磨损研究

以聚四氟乙烯（PTFE）乳液为主要润滑成分,通过辅助添加剂制备了新型复合高分子水基润滑剂,并进行均匀设计试验获得最优的成分配比。基于Deform有限元模拟镦粗试验探究润滑剂的摩擦行为,通过SEM和EDS表征方法研究润滑机理,发现润滑性能的提高是由于PTFE在基体表面形成了一层转移膜,h-BN吸附在基底表面保护了PTFE膜而有效降低了基体表面阻力,提高了润滑剂的润滑性能,此润滑剂可用于冷挤压成形的润滑。     

电弧离子镀(Ti,Nb)N硬质薄膜断裂韧性对摩擦学性能的影响

利用电弧离子镀方法，对独立的Ti靶和Nb靶的弧电流进行控制，在高速钢（HSS）基体上制备了不同成分配比的（Ti，Nb）N薄膜。采用压痕试验和滑动摩擦磨损对（Ti，Nb）N薄膜的断裂行为与摩擦学性能进行了研究。试验结果显示：在较小的载荷条件下（F=300N），膜层的显微硬度起主要作用；而在较高的载荷条件下（凡=60HDN），膜层的断裂性能起主要作用。梯度薄膜在较大的载荷条件下，具有良好的滑动摩擦性能。     

含纳米CeO2，Cu混合物添加剂润滑油摩擦学性能研究

本文中将纳米二氧化铈与铜粒子混合物应用于润滑油添加剂，使润滑油具有优良的减摩、抗磨性能。纳米二氧化铈与铜粒子用适当的表面活性剂进行表面改性处理，经表面改性的纳米粒子在润滑油中具有良好的分散、稳定性。采用透射电镜（TEM）观察与测量纳米二氧化铈、铜粒子的形貌和平均直径。应用四球摩擦磨损试验机测定添加纳米二氧化铈、铜粒子的润滑油的极压性能（PB）、磨痕直径（WSD）和摩擦因数（μ）等。研究结果表明，最佳的纳米二氧化铈、铜粒子的总添加量为0．6％左右、纳米二氧化铈、铜粒子的质量分数之比为1：1，该润滑油具有最佳的的减摩、抗磨作用。文中还探讨了纳米二氧化铈、铜粒子混合物具有优良摩擦学性能的机理。     

宽温域连续润滑材料的研究进展

航空、航天及核电等高新技术产业中苛刻工况下相关运动部件的润滑和耐磨问题是影响整个系统可靠性和寿命的主要因素,因此对具有宽温域连续润滑功能的新型润滑材料提出了越来越迫切的需求。文中综述了自润滑复合材料、"发汗"润滑材料、PS/PM自润滑涂层及温度"自适应"润滑涂层的研究成果,包括润滑剂及复配的选择依据、新型润滑剂对宽温域连续润滑材料组织结构、摩擦学行为、摩擦化学反应、润滑机理等的影响,并对不同润滑剂材料体系的宽温域连续润滑材料进行了系统的总结,在此基础上展望了宽温域连续润滑材料的发展趋势。     

羟基硅酸镁在润滑领域的应用研究进展

针对国内外关于羟基硅酸镁纳米微粒在润滑领域的研究报道进行了详细综述。首先，从羟基硅酸镁的结构特点入手，介绍了其在摩擦学领域的应用，然后列举了羟基硅酸镁纳米微粒的制备方法，总结了化学方法合成羟基硅酸镁纳米微粒过程中的不同反应条件，以及对其形貌调控的影响作用。其次，针对改善羟基硅酸镁在润滑油中的分散稳定性而采用的方法进行了概括。随后讨论了羟基硅酸镁纳米微粒在不同摩擦参数、摩擦对偶以及与稀土元素杂化的摩擦学性能变化规律，分析了其在摩擦副表面的摩擦膜形成机制与作用机理。在已报道的文献基础上，归纳总结了羟基硅酸镁纳米微粒能够产生抗磨减摩性能的潜在润滑机制。最后，提出了未来羟基硅酸镁纳米微粒在润滑领域应用推广所面临的问题与挑战，并针对已有问题给出了相应的解决思路。     

铁基含油轴承材料表面硫化改性及摩擦学性能

为改善边界润滑工况下铁基含油轴承材料的摩擦学性能,采用低温液体渗硫技术在材料表面形成一层固体渗硫层,微观检测渗硫层形貌与成分,并在端面摩擦磨损试验机上进行摩擦学实验,分析其摩擦磨损性能与自润滑机理。结果表明:渗硫层中固体润滑剂的主要成分为FeS,硫化物沿着基体孔道由材料表面向内部扩散,渗硫层的厚度约为15μm;与未硫化材料相比,硫化材料的摩擦因数明显降低,且硫化时间越长,轴承表面渗硫层的减摩性能越好;表面硫化改性后,利用轴承基体多孔含油与表面渗硫层的液固协同润滑作用,其综合摩擦磨损性能比单纯固体润滑或单纯油润滑的减摩性能都要好,边界润滑工况下的抗擦伤、抗咬合性能得到改善。     

微织构排布方式对水润滑轴承启停过程摩擦学性能的影响

梯度排布微织构在提升水润滑轴承摩擦学性能方面具有显著效果,然而梯度排布微织构在水润滑轴承中的应用仍缺乏系统性研究。为了探究梯度排布微织构对水润滑轴承启停过程摩擦学性能的影响,基于 Greenwood-Tripp 微凸体接触模型、 Archard 磨损模型求解轴瓦表面的磨损量。通过 CFT-I 材料表面性能综合测试仪对 CNC 雕刻机加工的织构化表面进行水润滑条件下的摩擦学试验研究。针对光滑、单一圆形织构、圆形与三角形以轴向交错平行（¹₁2 ）和周向交错平行分布（1212）方式梯度排布的表面,测量各个表面的磨损量和摩擦因数。通过立体显微镜、扫描电子显微镜对摩擦磨损试验前后的表面形貌和摩擦因数进行分析。数值模拟和试验结果显示,与光滑表面和单一织构化表面相比,梯度排布微织构化表面磨损量和摩擦因数显著降低;圆形与三角形以¹₁2 方式的梯度排布微织构化表面摩擦学性能最佳,接触表面磨损量最小、表面摩擦因数最低。 梯度排布微织构在流体润滑过程中相互影响,可以起到提高轴承表面举升力,减少表面接触,降低表面磨损和摩擦因数的作用。研究不同形状、排布方式下梯度排布微织构化表面的磨损量和摩擦因数的变化规律,可为舰船装备水润滑轴承研制阶段主动设计提供理论基础。     

纳米磁性流体与表面织构对钛合金的协同减摩作用机制

目的 提高钛合金表面的摩擦学性能。方法 采用纳秒激光器在钛合金表面构造沟槽型微织构图案,并以水基纳米磁流体和去离子水为润滑剂,利用UMT-3摩擦磨损试验机探究了织构与纳米磁流体的协同减摩作用机制。结果 分析了不同润滑条件下,沟槽型织构的分布间距对钛合金表面摩擦磨损性能的影响,在织构与纳米磁流体的协同作用下,钛合金表面的摩擦学性能得到改善,织构间距为250μm时的摩擦学性能最好,摩擦因数最大降低约51.5%,磨损率最大降低77.6%。当织构间距过小,织构化表面承载区减少,导致织构磨损较快,而织构间距过大会弱化织构效果。其次,以最优织构间距为基础,进一步探究了不同表面织构形貌和深度对钛合金表面摩擦学性能的影响。最后,研究了最优织构参数下,滑动速度和加载载荷对钛合金减摩性能的影响。结论 在润滑条件下,织构的表面形貌和深度影响钛合金表面的摩擦学性能,织构深度太浅或太深时,其流体动压效应都会减弱,从而导致摩擦因数和磨损量增大;当产生足够大的动压效应时,织构边缘的凸起结构能够对织构起到保护作用,延缓织构磨损。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。