不同表面处理等级下有机涂层失效行为的EIS研究

研究了不同表面处理条件下环氧富锌/环氧云母氧化铁/氯化橡胶涂层体系的电化学阻抗谱特征.利用EIS-Nyquist图、涂层电阻及涂层孔隙率的变化评价了表面处理对涂层防护性能的影响.结果表明,表面处理等级Sa2.5、St3、St2的金属/涂层阻抗谱各呈现一种谱形,可分别用一种等效电路模型表示.随着表面处理等级降低,涂层电阻下降,涂层孔隙率升高.表面处理Sa2.5金属/涂层体系的涂层电阻高于108Ω·cm2,涂层具有优良的防护性能;表面处理St2金属/涂层体系腐蚀后的涂层电阻仅为105Ω·cm2左右,孔隙率接近0.1%,涂层基本失去防护作用.     

钛合金表面抗氧化技术的研究进展

综述了钛合金表面抗氧化技术的研究进展,对钛合金表面抗氧化涂层,包括TiAlN涂层、NiCrAlY涂层、TiAl(Cr)涂层和搪瓷涂层及其表面合金化处理技术,包括渗铝及多元共渗、双层辉光等离子表面冶金技术、激光表面合金化和离子注入等进行了详细介绍,并指出了钛合金表面抗氧化技术今后的发展方向。     

梯度涂层结构设计制备及应用研究现状

梯度涂层以其优异的物理及力学性能表现出巨大的工程应用前景,在航空、航天及原子能等领域有着广泛的应用。对梯度涂层结构设计、制备方法、工艺及梯度涂层组元材料匹配的国内外研究现状进行综述,分析梯度涂层在机械零件表面应用过程中存在的问题。为将梯度涂层应用到机械零件表面改性处理上,提出需要建立和完善适合机械零件表面的梯度涂层结构设计模型,并开展梯度涂层组元材料匹配性能的研究。     

陶瓷颗粒表面Fe涂层的获得及其应用

研制了适合陶瓷颗粒表面涂层处理的化学气相沉积装置,并探索了氧化铝颗粒表面获得Fe涂层的工艺;所获得的Fe涂层可明显改善氧化铝颗粒与耐热钢液之间的湿润性;用铸渗法制备的该氧化铝颗粒/耐热钢基复合材料具有一定的铸渗层深度,组织致密,颗粒分布均匀.     

火车车轮轮毂加工用刀片涂层的研究

为了满足现代高速列车关键零部件的精密加工的需求,通过对涂层结构及表面的优化设计,开发了一种新型的适合高强度加工的涂层工艺技术。对开发的新型硬质合金涂层刀具进行了扫描电镜(SEM)、表面粗糙度检测及现场切削测试等分析。研究表明,制备的新型涂层刀具在经过优化处理后,能有效地改善刀具的各项性能,大幅度提高刀具寿命。     

微喷砂前处理对AlCrN涂层刀具表面完整性的影响

对YG8硬质合金进行微喷砂前处理,然后采用物理气相沉积法制备AlCrN涂层。研究微喷砂前处理工艺参数对涂层表面完整性(表面形貌、表面粗糙度、表面硬度及表面应力)的影响。结果表明,合适的微喷砂参数(P=0.3 MPa,T=30 s)可以减少涂层刀具表面缺陷,降低涂层刀具的表面粗糙度Ra,提高涂层刀具显微硬度和表面残余应力。探究了微喷砂前处理对涂层刀具表面完整性的影响规律,优化了微喷砂工艺参数,有助于推动涂层刀具表面处理技术的发展。     

半透明材料涂层的红外检测

为了能快速、大面积检测不同基底材料上半透明材料涂层的厚度,研究了主动式红外热成像技术测量涂层厚度的方法.用脉冲可见光热源激励涂层试件表面,红外热像仪实时监控表面脉冲激励前后温度的变化.由于半透明的涂层材料吸收可见光能量不满足面吸收的条件,对其表面进行了喷涂黑漆处理.比较喷漆前后的对数温度时间变化曲线和微分对数温度时间变化曲线,并根据喷漆后的二阶微分曲线的峰值时间来测量涂层厚度.实验结果显示:半透明涂层材料表面处理后满足红外测量要求,厚度范围在0.8～1.7 mm的涂层,测量精度达0.09 mm,表明红外检测方法可以非接触、快速、大面积、定量地进行半透明材料涂层厚度的测量.     

不同抛光工艺对涂层形貌及其摩擦磨损性能的影响

该文揭示了不同抛光工艺对涂层表面形貌及涂层与密封间摩擦匹配性能影响规律.分别利用不同目数的膜基砂带和布基砂带,对等离子喷涂Cr2O3-TiO2陶瓷涂层进行抛光处理,采用粗糙度仪、三维光学显微镜分析了不同抛光工艺下涂层表面轮廓特征,以摩擦系数和磨损失重量分析了不同抛光工艺下涂层与密封间摩擦匹配性能.结果表明,涂层表面质量...     

表面处理对TiAlSiN涂层刀具表面完整性及切削性能的影响研究

涂层刀具在高速干切削钛合金时容易出现刀具磨损严重、刀具寿命短等问题,对涂层刀具进行表面处理能改善涂层刀具的表面完整性,是提高涂层刀具耐磨性和切削寿命的有效途径。选取TiAlSiN涂层刀具,分别进行深冷处理、微喷砂处理和深冷+微喷砂处理,研究不同处理方法对涂层刀具表面完整性(包括表面形貌、表面粗糙度、显微硬度和表面残余应力等)的影响,并进行钛合金高速干切削试验,分析不同处理方法对涂层刀具切削性能的影响,探究提高涂层刀具耐磨性和切削寿命的方法。结果表明：与单一深冷处理和微喷砂处理相比,深冷+微喷砂处理后涂层刀具表面完整性明显改善,刀具寿命显著提高。深冷+微喷砂处理能减少刀具崩刃、月牙洼磨损和磨粒磨损,有效提高涂层刀具耐磨性。     

模具钢表面多弧离子镀CrAlN涂层的制备及其摩擦性能研究

为了改善模具钢表面质量,采用多弧离子镀技术在H13模具钢表面沉积CrAlN薄膜,探讨H13钢基体表面渗氮处理后对薄膜表面形貌、硬度、结合力、抗氧化性和摩擦磨损性能的影响。结果表明：基体表面渗氮处理前后制备的CrAlN涂层表面均匀致密,都有少量的大颗粒,涂层表面均呈CrN（200）面择优取向,而渗氮后制备的涂层CrN（200）面择优取向更强;基体H13钢经过表面渗氮后,硬度显著提高,对制备的涂层具有支撑作用,降低了裂纹产生倾向,提高了涂层产生裂纹的临界载荷,提高了涂层的膜基结合力;相较于基体表面未渗氮处理制备的CrAlN涂层,基体表面渗氮后制备的CrAlN涂层具有更高的硬度和结合力,更为优异的摩擦磨损性能,且抗高温氧化性能显著增强。     

活塞环耐磨涂层及其摩擦磨损机理研究进展

活塞环面临着极为严重的磨损问题,目前工业界广泛采用涂层技术来提高其耐磨性。对近年来活塞环表面耐磨涂层制备技术及相关材料进行了综述,分析了活塞环表面摩擦磨损机理的研究成果及存在的问题,总结了相关磨损实验装置的研究进展。     

Interfacial Stress and Failure Analysis for Piston Ring Coatings under Dry Running Condition

A two-dimensional thermomechanical finite element model was developed to analyze the sliding process of a piston ring with coating sliding on cylinder liner under dry running condition. Thermal and mechanical effects were considered simultaneously in the model. The aim of the current work is to study the mechanisms of scuffing, failure, and seizure occurrence in a piston ring-liner system. It is shown that coating thickness plays an important role in the thermal and mechanical stress status at the contact area, coating bulk body, and interface of the coating and piston ring substrate. The coating thickness also exhibits a significant influence on the temperature rising at the contact area and interface of the ring coating and substrate, which could cause failure at the interface of the coating and substrate before it happens at the contact surface under some specific conditions. The results also show that thinner coating thickness in some specific range could have a higher possibility of cracking or failure. Furthermore, it is found that the thermal loading is the key cause of scuffing or failure of the piston ring coating.     

镁合金有机涂层特性研究

应用3种工艺对常用的变形镁合金进行了粉末材料表面涂覆试验,分别对其结构和性能进行测试.结果表明,ZK60镁合金经静电喷涂耐高温漆后耐腐蚀性较好;但经阴极电泳喷涂,表面出现小点,涂层不均匀,且厚度薄;粉末涂层较厚且均匀,外观平整光滑、色泽鲜艳,适用作装饰产品.     

Microstructure and Mechanical Behavior of in Situ Primary Si/Mg_2Si Locally Reinforced Aluminum Matrix Composites Piston by Centrifugal Casting

Al-Si pistons are frequently damaged by burning piston top surface due to elevated combustion temperature, and by rubbing the first ring groove against the engine cylinder liner. To prevent piston from these damages, some technologies were invented, such as mounting high Ni cast iron ring around the first ring groove in Al alloy piston body and thermal resistant steel on piston top surface, and fabricating Al composite pistons by squeeze casting for enhancing the whole or local piston performance. In this paper, composite pistons locally reinforced with in situ primary Si and primary Mg2Si particles are fabricated by centrifugal casting. The microstructure characteristics, hardness and wear resistance of the composite piston are investigated and the motion characteristic of the in situ particles in centrifugal field is analyzed. The results of the experiments show that primary Si and Mg2Si particles mix up with each other in melt and segregate at the regions of piston top and piston ring grooves under the effect of centrifugal force. Particulate reinforced regions have a higher hardness and better wear resistance compared with the unreinforced regions and this performance increases after heat treatment. The analysis result of particle movement shows that, primary Si and primary Mg2Si particles move at approximately the same velocity in the centrifugal field, because of the growth of primary Si and fusion after colliding between primary Si particles, which compromised the velocity difference of primary Si and primary Mg2Si particles caused by the difference of their densities. Research results have some theory significance and applicative value of project in development of new aluminum matrix composites piston products.     

Tribological Behaviors of Molybdic Acid–Modified Phenolic/Polyfluo Wax Composite Coating

Phenolic resin (PF) and molybdic acid–modified phenolic (Mo-PF) have been synthesized and developed and combined with polyfluo wax (PFW) to fabricate PF-PFW and Mo-PF-PFW composite coatings. The effects of applied load and sliding speed on the tribological properties of the phenolic composite coating were evaluated using a block-on-ring wear tester. Compared to the PF composite coating, the Mo-PF displayed a lower friction coefficient and a higher wear life under all tested conditions. Scanning electron microscope (SEM) investigation showed that the Mo-PF composite coating had a smooth worn surface after the friction test, and a continuous and uniform transfer film was formed on the surface of the counterpart ring. The improved tribological properties of Mo-PF composite coating resulted from its enhanced thermal properties.     

提高塑料模具使用寿命的表面强化技术

从表面淬火、表面扩散化学热处理和表面覆层强化三方面介绍了提高塑料模具使用寿命的表面强化技术。指出正确运用表面强化技术是提高塑料模具使用寿命的一个行之有效的途径,具有事半功倍之效。     

表面技术及其在模具中的应用

简要介绍了模具行业中用到的三大类表面技术（表面组织转化技术、表面涂镀层技术和表面合金化技术）中若干种表面处理技术的原理,概述了各种技术的优点、缺点及应用范围,并举例说明了各项技术在模具研究或实际生产中的应用效果,最后指出了表面技术的发展方向,并呼吁在模具行业加强表面技术的推广应用。     

基于斯特封的往复密封摩擦磨损界面性能实验研究

斯特封是常用的往复密封件,其中斯特封的PTFE圈性能及活塞杆表面材料在往复密封过程中起着重要作用。搭建往复密封实验台,取4组添加碳纤维PTFE的密封圈分别与镀Cr膜活塞杆和镀DLC膜活塞杆进行往复密封台架实验,实验后获取使用过的4组密封圈作为实验样本,并取1个全新未使用的添加碳纤维PTFE的密封圈作为参考样本。通过三维白光干涉表面形貌仪、场发射环境扫描电子显微镜和冷场发射高分辨扫描电子显微镜分别对实验样本的密封唇进行表面形貌、表面磨损和磨损表面元素进行测定。通过实验测定,得出镀膜材料脱落形成磨粒导致密封圈表面磨损。还对密封圈的加工方法和活塞杆镀膜材料的选择提出了建议。     

Characterization of multilayer pvd nanocoatings deposited on tungsten carbide cutting tools

The present trends in the coating technologies are gradient coatings, metastable coatings, multicomponaent coatings and multilayer or super lattice coatings. The physical vapour deposition (PVD) process is well-suited technology for these advanced coating technologies. The performance of the coated tools can be improved considerably using multi-layer micro and nanocoatings. The present paper discusses the deposition and characterization of multilayer TiN/Al₂O₃ coatings on cemented tungsten carbide cutting tools using reactive sputtering. The characterization of the coatings was carried out using X-ray diffraction (XRD) for phase analysis, chemical composition using EDAX, adhesion and toughness evaluation using Rockwell indentation test and surface roughness. It was observed that with decrease in thickness of each alumina layer to nanolevel in multilayer coating system results considerable improvement in final surface finish, adhesion and toughness of the coating. The experimental results are presented and analyzed in this paper.     

表面工程技术抗微动损伤的研究现状

总结了工业中抗微动损伤的基本途径，指出了表面工程技术减缓微动损伤的重要作用，并从表面机械强化、扩散处理、表面化学处理、电沉积、热喷涂、气相沉积、高能密度处理和固体润滑涂层等表面工程分支综述了目前的研究现状。介绍了作者在径向和复合微动中的最新研究进展。