紫外光固化手机涂料附着力和耐磨性的研究

介绍了紫外光固化的概念,讨论了预聚物、活性稀释剂以及添加剂对紫外光固化手机涂料附着力和耐磨性的影响。     

真空熔烧钴基合金--碳化钨复合涂层材料的耐磨性能研究

采用真空熔烧法制得钴基合金——碳化钨复合涂层材料,借助扫描电子显微镜、X射线衍射仪、显微硬度计等先进的测试手段对涂层的组织结构和表面形貌进行观察分析。应用盘销式摩擦磨损试验机对不同碳化钨含量的复合涂层材料和淬火态45钢进行了磨损试验。试验结果表明,在相同试验条件下,复合涂层的耐磨性显著高于淬火钢,且其耐磨性随碳化钨含量的增加而提高,淬火钢的耐磨性随着载荷的增加迅速降低,而复合涂层的耐磨性则变化不大。     

Microstructures and mechanical properties of multi-component (AlCrTaTiZr)NxCy nanocomposite coatings

Multi-component (AlCrTaTiZr)N_xC_y coatings with the incorporation of quinary metallic elements and different N and C contents were deposited by AlCrTaTiZr/C co-sputtering in an N₂/Ar mixed atmosphere under an AlCrTaTiZr-alloy-target power of 150 W and different C-target powers (0-200 W). At a C-target power of 0 W, an (AlCrTaTiZr)N_0.6 coating with a face-centered cubic solid-solution structure was deposited and exhibited a large columnar structure; its hardness and steady-stage creep strain rate were measured as about 20 GPa and 1.5 × 10⁻⁴ 1/s, respectively. By applying a C-target power of 100 W, an (AlCrTaTiZr)N_0.6C_0.2 coating was formed with a fine columnar structure. Owing to the incorporated C atoms, the (111) interplanar spacing of the face-centered cubic structure was increased from 0.249 to 0.253 nm. The hardness increased to 32 GPa and the creep strain rate was lowered to 1.1 × 10⁻⁴ 1/s attributed to the introduction of covalent-like bonds, grain refinement and the formation of an amorphous-like and nanocomposite structure. Furthermore, under a C-target power of 200 W, excess C atoms agglomerated to form clusters in the deposited (AlCrTaTiZr)N_0.6C_0.4 coating. Consequently, the hardness slightly decreased to 30 GPa and the creep strain rate increased to 2.4 × 10⁻⁴ 1/s.     

Superior wear resistance of diamond and DLC coatings

As the hardest known material, diamond and its coatings continue to generate significant attention for stringent applications involving extreme tribological conditions. Likewise, diamond-like carbon (DLC, especially the tetragonal amorphous carbon, ta-C) coatings have also maintained a high level interest for numerous industrial applications where efficiency, performance, and reliability are of great importance. The strong covalent bonding or sp³-hybridizaiton in diamond and ta-C coatings assures high mechanical hardness, stiffness, chemical and thermal stability that make them well-suited for harsh tribological conditions involving high-speeds, loads, and temperatures. In particular, unique chemical and mechanical nature of diamond and ta-C surfaces plays an important role in their unusual friction and wear behaviors. As with all other tribomaterials, both diamond and ta-C coatings strongly interact with the chemical species in their surroundings during sliding and hence produce a chemically passive top surface layer which ultimately determines the extent of friction and wear. Thick micro-crystalline diamond films are most preferred for tooling applications, while thinner nano/ultranano-crysalline diamond films are well-suited for mechanical devices ranging from nano- (such as NEMS) to micro- (MEMS and AFM tips) as well as macro-scale devices including mechanical pump seals. The ta-C coatings have lately become indispensable for a variety of automotive applications and are used in very large volumes in tappets, piston pins, rings, and a variety of gears and bearings, especially in the Asian market. This paper is intended to provide a comprehensive overview of the recent developments in tribology of super-hard diamond and DLC (ta-C) films with a special emphasis on their friction and wear mechanisms that are key to their extraordinary tribological performance under harsh tribological conditions. Based on the results of recent studies, the paper will also attempt to highlight what lies ahead for these films in tribology and other demanding industrial applications.     

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.     

Research on cavitation erosion and wear resistance performance of coatings

Depending on the nature of the working medium and working conditions, corrosive and cavitation damage shall arise to pump’s components. In industrial applications the corrosion-reducing coatings are sprayed on hydraulic components. But it is questionable whether such products actually do help under wear or cavitation loads or not. Abrasive jet wear tests were carried out to determine the wear resistance of coating materials: polymers and ceramics, cast iron, and steel of various types. The samples were loaded for five hours, and finally the wear depth was measured as a determining indicator of the sample’s wear resistance. Results of investigation on anti-erosion performance of epoxy resin, ceramic and Polyurethane (PU) coatings brushed on alloy steel surface were also presented. Cavitation erosion tests were performed on the ultrasonic rig. The mass loss and surface morphology of the specimens were examined by balance analysis and 3-D laser microscopy, respectively. The investigations showed excellent wear-resisting performance of ceramic coatings, which is better than wear-resistance of stainless steel, cast iron and high chrome alloy steel. But the excellent wear-resisting performance could not guarantee a good erosion-resisting performance. The ceramic coatings’ anti-erosion performances were inferior to that of gray cast iron, and hardly comparable to those of stainless steels. The basic factors that influenced coating’s cavitation erosion endurance were adhesion and thickness of coatings. Analysis of coating’s degradation mechanism showed that PU coatings could withstand longer incubation period thus enhancing the materials’ cavitation erosion resistance. Several practical cases were analyzed, showing some guidance for coatings’ application.     

Endurance and wear resistance of steels with vacuum-diffused coatings

The fatigue strength and wear resistance of steels St. 3, P-1, EI-802, and EI-612 after vacuum-diffusion chromizing, siliciding and boriding was studied. It was shown that the wear resistance of carbon steels is increased more than 20-fold by boriding, being approximately doubled by chromizing, and increased 1.3 times by siliciding. Of the alloy steels, only steel EI-612 has its wear resistance increased by vacuum chromizing. The fatigue strength was reduced in every case by 20–50%.     

铝含量对（Ti,Al）N镀层结构及耐磨性的影响

运用多弧离子镀在Ｗ６Ｍｏ５Ｃ４Ｖ２高速钢表面沉积了（Ｔｉ,Ａｌ）Ｎ镀层,并经ＳＥＭ,ＸＲＤ和ＥＤＳ等方法分析表明,多靶联合工作获得的（Ｔｉ,Ａｌ）Ｎ镀层,其成分可连续变化,随弧流增大,铝含量增多;随负偏压增大,铝含是降低。弧流与偏压二者对镀层的成分均有影响,其中弧流较为显著。     

Enhancement of wear and corrosion resistance of metal-matrix composites by laser coatings

A novel technique based on laser-induced chemical reduction of metal salts has been developed to produce surface coatings on metal-matrix composites (MMCs). The substrate is predeposited with a paste, containing concentrated salts of the elements to be coated along with a thickening agent, and then subjected to high power laser radiation. The rise in surface temperature during laser irradiation led to the decomposition of salts to their native metals. The combination of metal and metalloid elements in the reaction zone forms an amorphous layer due to the specific chemical ratio and rapid cooling rate. The thickness of the coatings obtained were of the order of 50–100 m. The coatings exhibited amorphous and microcrystalline structures, possessed hardness in the range of 300–1700 H_v (substrate hardness 80–90 H_v), had superior sliding wear resistance and excellent corrosion resistance. The advantages of this process include the formation of complex coatings on MMCs by a simple, versatile technique which does not require any vacuum or inert atmosphere.     

Structural and mechanical properties of multi-element (AlCrMoTaTiZr)Nx coatings by reactive magnetron sputtering

(AlCrMoTaTiZr)N_x high-entropy films were deposited on silicon wafer and cemented carbide substrates from a single alloy target by reactive RF magnetron sputtering under a mixed atmosphere of Ar and N₂. The effect of nitrogen flow ratio R_N on chemical composition, morphology, microstructure, and mechanical properties of the (AlCrMoTaTiZr)N_x films was investigated. Nitrogen-free alloy film had an amorphous structure, while nitride films with at least 37 at.% N exhibited a simple NaCl-type FCC (face-centered cubic) structure. Mixed structures occurred in films with lower nitrogen contents. Films with the FCC structure were thermally stable without phase decomposition at 1000 °C after 10 h. The (AlCrMoTaTiZr)N film deposited at R_N = 40% exhibited the highest hardness of 40.2 GPa which attains the superhard grade. The main strengthening mechanisms for this film were grain-size and solid-solution strengthening. A residual compressive stress of 1.04 GPa was small to account for the observed hardness. The nitride film was wear resistant, with a wear rate of 2.8 × 10^− 6 mm³/N m against a loaded 100Cr6 steel ball in the sliding wear test. These high-entropy films have potential in hard coating applications.     

Structure and wear resistance of R6M5 steel based coatings

Features of the structure of R6M5 steel based coatings obtained by multiscan electron-beam fusion of a hardening composition in vacuum have been studied. It is established that the carbide subsystem of the hardened layer is characterized by a multimodal distribution of carbide particles with d ₁ = 3.8 μm, d ₂ = 0.65 μm, and d ₃ < 0.25 μm. The volume fraction of M₆C secondary carbide and retained matrix austenite can be controlled within broad limits by varying thermal parameters of the electron-beam fusion. An increase in the retained austenite fraction in the coating leads to improved wear resistance due to the γ → α′ marten-site transformation during friction and the presence of dispersed secondary carbides inside the matrix grains.     

Filter effects on the wear and corrosion behaviors of arc deposited (Ti,Al)N coatings for application on cold-work tool steel

In this study, (Ti,Al)N coatings were deposited on Japanese Industrial Standard SKD11 modified cold-work tool steel using a cathodic arc deposition system with and without magnetic filter attachment. Coating morphology and properties such as coating structure, adhesion, hardness, abrasion and corrosion behaviors were analyzed to evaluate the effects of magnetic filter on the coatings. The results showed that magnetic filtering slowed down (Ti,Al)N deposition rate, but it improved component homogeneity, roughness and adhesion of the coatings. Although (Ti,Al)N coated specimens produced with or without filter both showed superior abrasion resistance in service, however, filtered (Ti,Al)N coatings yielded better corrosion protection of the steel than unfiltered ones in 3.5 wt.% NaCl aqueous medium.     

TC4钛合金微弧氧化复合陶瓷膜制备及耐磨性能研究

采用微弧氧化技术,通过向电解液中分别添加不同的陶瓷颗粒(SiC、SiO2),在TC4钛合金表面制备复合陶瓷膜。采用扫描电镜(SEM)、X射线衍射仪(XRD),MMA-1万能摩擦磨损实验机研究了不同的陶瓷颗粒对膜层微观组织结构、元素分布特征、相组成和耐磨性能的影响。结果表明,在电解液中添加陶瓷颗粒都能使膜层表面变得致密平整且膜层的厚度增加。陶瓷颗粒能够进入氧化层中,但并不发生相变反应。SiC和SiO2颗粒能显著提高膜层耐磨性能。     

基于自润滑C(Cr,N)镀层钢球轴承的速度性能研究

应用非平衡磁控溅射离子镀技术在6204轴承钢球表面制备出自润滑C(Cr,N)镀层。运用扫描电子显微镜和透射电子显微镜对镀层的微观结构进行了观察分析;测试了镀层的结合强度、硬度、韧性及摩擦特性;用高性能轴承试验台对镀层钢球轴承和无镀层轴承的速度性能及其自润滑性能进行了实验,并对其给予对比分析。研究结果表明,制备的C(Cr,N)镀层具有良好的微观结构和综合的机械性能;与无镀层轴承相比,镀层明显减小了轴承的振动,极大地提高了轴承的高速性能和自润滑性能。     

Anti-slip and wear resistance performance of three novel coatings as surface course of airstrip

Airstrip can be used to cater to the emergency need of an airport. For shortening construction time, the surface course should be handled as fast as possible. This paper explores the carboxylic styrene butadiene latex (CSBL), waterborne epoxy resin (WER) and modified polyurea elastomer (MPE) for any possibility to be used as surface course for an airstrip. The anti-slip test and the wear resistance test were performed to evaluate the coatings’ anti-slip and wear resistance performance. Test results indicate that: (1) The British Pendulum Number (BPN) of stabilised and reinforced soils meets the specifications. The BPN increases with the increase of cement and fibre contents. Samples with surface course can meet the requirements of BPN in a dry state; however, the BPN is slightly lower than that of the requested value in a wet state. When the sand is added to the coatings, the BPN can meet the requirements and its value ranges between 36.8 and 49.9; and (2) Cement and fibre enhance the wear resistance performance of samples. The wear mass per unit area of stabilised soil is less than half of the plain soil. As the content of fibre increases from 0.3 to 0.8%, the wear mass per unit area decreases from 19.4 to 11.8 kg/m² as well as the wear depth decreases from 3.33 to 2.69 mm. The functional surface course can greatly enhance the performance of wear resistance. The enhancement of MPE can be regarded as the most significant. The addition of sand slightly improves the performance of wear resistance for CSBL and WER. The MPE can meet the requirements of anti-slip and wear resistance performance of airstrip’s surface course.