树脂基复合材料表面功能防护涂层的研究现状

树脂基复合材料因具有综合成本低、减重性能好、比强度高、比刚度高、耐腐蚀和性能可设计等优点,在航空航天领域已广泛用于替代现有的部分金属部件;然而树脂基复合材料较差的抗氧化与耐磨损性能以及较低的使用温度限制了其更广泛的应用。综述了树脂基复合材料表面功能防护涂层的国内外研究进展,探讨了不同涂层制备方法、防护性能及其失效机理,为未来涂层的研究提供基础,以解决涂层制备工艺及其服役寿命问题。     

光学显示双膜系PC镜片的设计与制备

光学显示仪器前的镜片需要通过镀膜来对特定波段形成高反射。以聚碳酸酯(PC)镜片作为基底,采用真空镀膜技术,在PC镜片上镀高反射膜和增透膜,研究了增透膜对消除PC镜片表面二次反射的影响。研究结果表明,PC只有前表面镀反射膜的反射曲线在530 nm处波长的反射率达到85.05%,同时在PC镜片前面镀反射膜和PC镜片后面镀增透膜的反射曲线在530 nm处波长的反射率达到78.33%。PC镜片的反射率降低了6.72%。     

新型耐烧蚀树脂基体的研究进展

综述了国内外新型耐烧蚀树脂基体的研究进展.根据对耐烧蚀树脂基体的评价,介绍了改性酚醛树脂及芳基乙炔等新型耐烧蚀树脂基体的性能及其应用概况,并指出高性能、低成本是今后耐烧蚀树脂基体的发展方向.     

粘结MoS2基钼固体润滑膜的抗承载能力和耐速度性能研究EI

为了探讨粘结MoS2基固体润滑膜在干摩擦条件下的抗承载能力和耐速度性能,使用国产的环一块摩擦磨损试验机在干摩擦下对粘结MoS2基固体润滑膜在不同载荷和不同速度试验条件下的摩擦磨损性能进行了研究.试验结果表明:粘结MoS2基固体润滑膜的承载能力有高达2100N,在0.512～3.84m/s的滑动速度范围内具有良好的抗磨减摩性能.对转移膜的研究结果表明高载高速试验条件有利于促进对偶表面生成高质量的转移膜.粘结MoS2基固体润滑膜具有良好的抗承载能力和耐速度性能的机理应归结于在摩擦过程中对偶表面高质量转移膜的生成.     

粘结MoS2基钼固体润滑膜的抗承载能力和耐速度性能研究

为了探讨粘结MoS2基固体润滑膜在干摩擦条件下的抗承载能力和耐速度性能,使用国产的环一块摩擦磨损试验机在干摩擦下对粘结MoS2基固体润滑膜在不同载荷和不同速度试验条件下的摩擦磨损性能进行了研究.试验结果表明:粘结MoS2基固体润滑膜的承载能力有高达2100N,在0.512～3.84m/s的滑动速度范围内具有良好的抗磨减摩性能.对转移膜的研究结果表明高载高速试验条件有利于促进对偶表面生成高质量的转移膜.粘结MoS2基固体润滑膜具有良好的抗承载能力和耐速度性能的机理应归结于在摩擦过程中对偶表面高质量转移膜的生成.     

SiC含量对环氧/SiC复合材料冲蚀磨损性能的影响

为了改善工厂、矿山中大型机件的耐冲蚀磨损性,利用SiC颗粒与环氧树脂制备了能够便捷涂覆和快速固化具有优异耐冲蚀磨损性能的环氧/SiC复合材料,着重考察了SiC含量对环氧/SiC复合材料冲蚀磨损性能的影响。用自制的冲蚀磨损试验机对复合材料进行了冲蚀磨损实验,采用SEM等手段对复合材料的冲蚀磨损形貌进行观察分析。结果表明:在复合材料中提高SiC含量可以提高其耐冲蚀磨损性能,当SiC质量分数为复合材料的66.66%时,SiC颗粒与树脂之间"阴影效应"和"粘接效应"相互配合达到最佳,复合材料的冲蚀磨损性能最好;当SiC含量最佳时,复合材料的耐冲蚀磨损性能要好于相同角度下白口铸铁。     

Ni-SiC脉冲电镀工艺对SiC共沉积量及镀层耐磨性的影响

采用脉冲电镀法制备了Ni-SiC复合镀层,考察了镀液中SiC质量浓度、脉冲平均电流密度、镀液pH值对复合镀层中SiC共沉积量及镀层耐磨性能的影响.结果表明:电镀工艺参数的改变影响镀层中SiC的共沉积量以及复合镀层的耐磨性.选择适当的工艺参数,可以制备出SiC共沉积量高、微粒弥散较均匀的耐磨复合镀层.复合镀层的抗磨性能不仅与硬质微粒的共沉积量有关,而且与微粒在镀层中分布的均匀性有很大关系,在共沉积量相同的情况下,微粒的分散性越好,镀层的抗磨损性能就越好.     

热浸镀高铬铸铁层热处理前后的组织及耐冲蚀磨损性能

通过热浸镀技术制备高铬铸铁涂层来提高材料的耐冲蚀磨损性能未见研究报道.采用热浸镀技术在碳钢表面制备了高铬铸铁涂层,利用光学显微镜、扫描电镜(SEM)和X射线衍射仪分析了涂层热处理前后的组织和物相,对涂层热处理前后的抗冲蚀磨损性能进行了比较,并观察了涂层冲蚀后的表面形貌.结果表明:涂层主要由γ-Fe,CrC和CrB组成,热处理后涂层中硬质相类型由CrC和CrB转变为Cr7C3和Cr23C6;热处理后涂层的抗冲蚀磨损性能与热处理前相比明显提高,磨损量仅为热处理前的60%.     

真空电弧离子镀膜方法沉积类金刚石膜在PMMA树脂义齿表面的应用

采用电弧离子镀膜方法,以高纯石墨为碳离子源在PMMA树脂义齿表面沉积类金刚石膜.应用xps谱和Raman谱对膜层的结构进行了理论分析,对镀膜样品进行了抗磨性能实验、病理实验和临床实验.结果表明为了提高样品的膜基结合强度,必须在DLC膜与基材之间增镀一层钛氧化物作为过渡层,必须严格控制工作电压、工作室的真空度和气氛配比.     

非均相固化体系对复合材料树脂微观力学均匀性的影响

采用热熔法制备预浸料涉及熔融树脂对纤维层的渗透,对于固化体系为非均相的环氧树脂基体,制备大厚度预浸料可能会受到固化剂分布不均的影响。利用纳米力学方法分别研究采用小厚度玻璃纤维预浸料制备的复合材料和通过树脂真空吸注工艺制备的玻璃纤维复合材料的内部树脂的微观力学均匀性。结果表明:由小厚度预浸料制备的复合材料,其内部树脂各区域具有较好的微观力学均匀性,各区域树脂的纳米硬度和耐磨损性基本相同,各铺层中心和边缘接近;通过树脂真空吸注工艺制备的复合材料则表现出明显的层状分布,固化剂和促进剂颗粒在纤维层外部富集,纤维层外层的树脂具有较高的纳米硬度和耐磨损性,而在纤维层内0.4mm深后的树脂纳米硬度下降,耐磨损性下降,纤维层内部的树脂纳米硬度很低。     

Herstellung und Untersuchung des Verschleißverhaltens von induktiv eingeschmolzenen Hardpaint‐Schutzschichten

Friction and wear processes generate significant economic damage annually in industrial production due to maintenance and repair costs as well as loss associated with production downtime. Wear‐resistant coatings are a measure for reducing wear. In this context, the novel hardpaint technology for coating of parts with a fusible metal powder composition is described. Components with complex geometries as well holes or undercuts can be coated easily and inexpensively. Two protective layers are discussed and characterized in terms of their microstructure. Density measurements, hardness tests and scanning electron microscopic investigations were carried out. Both powder layers were inductively melted after application and are based on a hard alloy (iron‐based) commonly used for plasma transferred arc powder surfacing. Abrasion wear resistance is evaluated based on the results of the wear tests and microstructural investigations. Furthermore the results are discussed in comparison to a martensitic fine‐grain steel (Hardox 450), which is commonly used in abrasively stressed areas. Compared to Hardox 450 both hardpaint coatings have a much more wear‐resistant behavior due to their hard phases. In addition, it was confirmed that the hardpaint technology is able to embed thermally sensitive fused tungsten carbides which are significantly increasing the wear resistance against abrasion.     

铝合金表面Ti-Al双丝超音速电弧喷涂涂层的组织与性能研究

利用SAS－1型超音速电弧喷涂设备和钛、铝丝在适当的工艺条件下，在LY12铝合金表面制成了钛铝合金复合涂层。并利用金相显微镜、X射线衍射仪、扫描电镜、X射线能谱仪、电子探针等，对涂层的成分、相结构、显微结构、孔隙率及其结合强度、显微硬度和耐磨性进行了研究。结果表明，利用超音速电弧喷涂设备，可以在铝基表面形成低孔隙率小于2.8%，结合强度为29MPa，显微硬度HV0.2为631和干滑动磨损体积仅为LY12基体1／7的TiAl合金涂层。显微组织观察发现，涂层与基体间有冶金结合的迹象，组织结构分析表明，涂层由TiN（TiO)，Al,Ti,TiAl,Ti3Al等相组成。涂层的磨损机制可能以化合物等硬质相的剥落引起的磨粒磨损和氧化磨损为主。     

Untersuchungen zur Beständigkeit thermisch gespritzter Schichten im Vergleich zu Hartchromschichten bei durch Abrasion dominierter tribologischer Beanspruchung

Investigations on thermal spray coatings resistance against abrasion dominated tribological load in comparison to hard chromium coatings HVOF iron and nickel based hard alloy as well as WC/Co(Cr) and Cr₃C₂/Ni20Cr coatings are compared to APS Al₂O₃/TiO₂ and Cr₂O₃, powder flame sprayed and fused composite coatings consisting of NiCrBSi and WC/Co and electrolytically deposited hard chromium coatings concerning their wear behavior for tribological load by lose abrasive particles (ASTM G65 and ASTM G75). Thereby the influence of newly developed HVOF torch combustion chambers with reduced critical diameter and divergent expansion nozzles that both permit increased combustion gas and therefore also particle velocities on microstructure and wear resistance of the produced coatings is studied. While there is no improvement of wear resistance for hard alloy coatings compared to mild steel substrates for the specific tribological boundary conditions of these tests, especially the carbide reinforced coatings permit improvement by more than one order of magnitude in ASTM G65 tests and even more than two orders of magnitude in ASTM G75 tests. Also, for both types of tribological load HVOF coatings with WC as reinforcing phase are clearly superior to electrolytically deposited hard chromium coatings. Both use of the combustion chamber with reduced critical diameter and the expansion nozzles with divergent contour result in improved wear resistance of the thereby produced coatings. The specific wear mechanisms are deduced based on SEM examination of worn specimen surfaces.     

Metallurgical aspects of steels designed to resist abrasion,and impact-abrasion wear

Many abrasion resistant steels rely on a martensitic microstructure to ensure hardness, which in general correlates with better wear performance. However, in practice the steel may be subjected to a complex combination of conditions where hardness alone may not be sufficient to ensure tribological performance. This review is a critical assessment of the mechanical and metallurgical parameters that control wear resistance of steel in impact-abrasion conditions, although relevant work dealing with abrasion has also been included. It is found, for example, that fracture toughness and work-hardening behaviour have a role in enhancing the wear resistance of hard steels.     

高硬度耐磨损电弧喷涂涂层研究

采用电弧喷涂方法制备的高硬度耐磨损JCW-B涂层可广泛应用于工业零部件耐磨表面.对涂层的组织、孔隙率、硬度、结合强度及耐磨粒磨损性能进行分析,对比研究该涂层与Ni60喷熔层的耐冲蚀性能.结果表明JCW-B涂层组织致密,孔隙率低于4%,显微硬度HV0.1高于1200,平均结合强度大于50MPa.研究了涂层的耐磨损机理,XRD结果显示涂层中主要含有Fe3B硬质相,对涂层起到弥散强化的作用.     

Tribology of metal coatings for electrical contacts

Noble metals are required for sliding low voltage low current electrical contacts such as those in electronic connectors, instrument slip rings and switches. This is to ensure that the contact resistance will be low and will remain stable. Gold, palladium and their alloys are the most commonly used materials and are employed primarily as electrodeposits and clad coatings.The major contact wear processes are adhesion, abrasion and fretting. Adhesive wear can operate in mild or severe regimes. Prow formation is the dominant wear process in the severe regime and is characterized by transfer from the member with the larger surface involved in sliding to that with the smaller surface, after which loose debris is formed. On repeat-pass movement, a transition to rider wear occurs in which the direction of metal transfer reverses. Unique gold electrodeposits have been developed that are relatively resistant to severe adhesive wear. These deposits are brittle, which lowers the tendency of adherent asperities at the mating surfaces to grow to large prows during sliding.Abrasive wear, in contrast, is accentuated when the coatings have low ductility, but as with other wear processes may be controlled if the contact materials are hard.Fretting wear of noble metal coatings leads to high contact resistance when they wear through to their base substrates. Frictional polymerization is the formation on the contact of insulating organic layers, which originate in organic air pollutants in the environment, and occurs during sliding and fretting of platinum group metals. Hard substrates and underplates are desirable because they reduce adhesive, abrasive and fretting wear. Smooth surfaces are superior to rough surfaces when adhesive and abrasive wear occur.     

Friction and wear reduction with tribological coatings

The basic requirements for a good tribological surface are (1) low sliding friction, (2) good resistance to scuffing, wear and abrasion, (3) long contact fatigue life and (4) adequate subsurface strength to provide dimensional stability. Coatings have inherent deficiencies. The major problem is failure at the interface between the coating and the substrate, which results in flaking, peeling or spalling of the coating under the repetitively applied contact stresses.Three types of coatings which employ different mechanisms to improve the tribological properties and to maintain coating integrity are described in this paper. Nitrocarburizing represents a class of coatings in which the elements are allowed to diffuse into the surface of the structural material to form an alloy with the substrate. Diffusion provides compositional gradients which result in hard wear-resistant surface and which at low shear strengths avoid the interfaces that frequently exist between coatings and substrates. Chemically vapor-deposited chromium and titanium carbides represent a class of coatings in which a chemically distinct layer is grown on top of the substrate and is bonded to the substrate by diffusion. In the third type of coating, hard particles are suspended in a soft matrix. The hard particles provide the wear and abrasion resistance and the soft matrix both bonds the particles together and provides the low friction. Although the bond strength of this coating to the substrate is lower than that provided by diffusion in the other coatings, the soft matrix will yield without flaking under the shear stresses which are developed at the interface.     

Erosive and abrasive wear resistance of overlay coatings

In the paper, the erosion and abrasion resistance of PTA, TIG and flame deposited coatings was investigated. Hardness of coatings has almost no effect on erosion resistance and incubation period. Microstructure of coatings has significant effect on erosive wear of coatings. No significant correlation was found between results of abrasive and erosive tests. Statistically significant correlation was found between erosive wear intensities determined in tests carried out at similar angles, the total content of B and C correlates with mass loss in abrasion test and erosive wear intensity at normal incidence. Laboratory tests with model abrasives cannot be used as a guide for material selection in industry.     

High-speed turning experiments on metal matrix composites

The hard abrasive ceramic component which increases the mechanical characteristics of metal matrix composites (MMC) causes quick wear and premature tool failure in the machining operations. The aim of the paper is to compare the behaviour of high rake angle carbide tools with their diamond coated versions in high-speed machining of an Al₂O₃Al 6061 MMC. The influence of the cutting parameters, in particular cutting feed and speed, on tool wear and surface finish has been investigated. The higher abrasion resistance of the coatings results in increased tool life performances and different chip formation mechanisms.     

纳米SiO2对聚丙烯酸酯复合涂层在水润滑下摩擦学性能的影响

考察了纳米SiO₂对聚丙烯酸酯复合涂层在水润滑下摩擦磨损性能的影响。利用FTIR分析纳米SiO₂与聚丙烯酸酯的界面结合;利用SEM观察复合涂层磨损表面,并结合FTIR和摩擦磨损实验分析其磨损机理。结果表明:水润滑时,聚丙烯酸酯在摩擦过程中会发生摩擦化学反应,引起涂层摩擦腐蚀磨损;而纳米SiO₂能与聚丙烯酸酯以化学键的形式结合,它的加入有助于摩擦界面在水介质中形成具有较好减摩作用的表面膜和水分子膜,提高聚丙烯酸酯复合涂层的耐磨性。在水润滑下,当纳米SiO₂的含量较低时,涂层表面的磨损形式为摩擦腐蚀磨损和磨粒磨损;当纳米SiO₂的含量达到5wt% 时,涂层表面形成完整的表面膜和水分子膜,此时涂层具有良好的摩擦学性能。