Recent developments in the preparation,characterization and applications of glass- and glass–ceramic-to-metal seals and coatings

There has, in recent years, been a major revival of interest in glass- and glass–ceramic-to-metal seals and coatings for new applications. Experience dictates that many factors need to be taken into consideration in the successful design and manufacture of high-quality seals, particularly if an adequate component lifetime is to be achieved. For example, during their preparation, undesirable reactions may occur between diffusing metal species and glass constituents, and these can lead to the formation of highly localized internal stresses, which can initiate failure of a seal either during manufacture or, more seriously, whilst in service due to the influence of static fatigue. In the case of high-temperature systems, reactions under hostile operating conditions also need to be taken into consideration. In this review, the factors learnt from past experience that influence the formation and lifetime behaviour of glass and glass–ceramic/metal systems are briefly introduced, and their relevance to the newer applications including solid oxide fuel cell sealants and coatings on titanium for biomedical applications is discussed.     

Vacuum-lamination process for metallized polymer films

Abstract

A process is described whereby polymer films are laminated using vacuum-deposited aluminium as an adhesive. Only modest pressures are needed to produce a pressure weld between the freshly deposited metal coatings. The influence of various process parameters on the metal–metal bonding is explored, with particular reference to surface contamination and deposition rate. In addition to their commercial potential, the laminates are particularly useful as test specimens for measuring metal–polymer adhesion.

MST/178     

炭/炭复合材料高温抗氧化涂层的研究进展

阐述了近年来国内外炭/炭复合材料高温抗氧化涂层在玻璃、贵金属、陶瓷以及复合涂层等涂层体系方面的新近展,总结了炭/炭复合材料高温抗氧化涂层在已有制备工艺的完善以及新工艺的开发等方面的最新研究成果,结合涂层炭/炭复合材料在航空、航天以及军事领域的应用背景对高温抗氧化涂层的下一步发展趋势进行了展望.指出：目前的研究结果尚达不到严酷环境下的应用要求,炭/炭复合材料高温抗氧化涂层下一阶段将向着长寿命、耐高温、抗冲刷和低成本的方向发展;涂层新工艺的开发和涂层与基体结合研究将是下一步的研究重点;多相复合涂层和梯度陶瓷涂层有望取得在高温冲刷环境下长时间应用的突破性进展.     

TiN/Ti多层膜调制比对摩擦磨损行为影响的研究

考察了TiN/Ti多层膜调制比对其摩擦磨损行为的影响. 采用磁过滤阴极弧沉积的方法制备了具有不同调制比的TiN/Ti多层膜, 用扫描电镜和透射电镜对其层状结构及子层结构进行了观察和分析. 用纳米压痕和SRV摩擦磨损试验的方法, 对多层膜进行了纳米硬度和弹性模量测试以及摩擦磨损实验. 结果表明, 所制备的TiN/Ti多层膜层状结构清晰, 与基底结合良好, 调制比对多层膜的硬度和磨损特性影响较大, 而对摩擦系数的影响却不明显. 结合实验结果, 讨论了硬度与弹性模量的比值(H/E值)对TiN/Ti多层膜耐磨性的影响.     

C/C复合材料高温抗氧化涂层的研究现状与展望

C/C复合材料在高温下的氧化严重制约了该材料在航空航天领域的推广应用,涂层技术是目前解决该材料高温易氧化的最佳手段.本文综述了C/C复合材料高温抗氧化技术在玻璃涂层、金属涂层、陶瓷涂层和复合涂层等体系方面的研究现状,总结了C/C复合材料高温抗氧化涂层在传统制备工艺的改善以及新方法的开发等方面取得的研究成果,并提出了C/C复合材料高温抗氧化涂层当前研究中存在的问题和今后潜在的发展方向.     

金属表面Sol-gel法制备耐腐蚀陶瓷涂层的研究进展

综述了溶胶－凝胶涂层的成膜原理，制备工艺，比较了溶胶－凝胶法与其它金属陶瓷涂层的制备工艺，讨论了溶胶－凝胶涂层对金属耐磨腐蚀性能，耐磨性能的改进及在腐蚀防护领域中的应用，还对溶胶－凝胶涂层技术的发展的提出了看法。     

Verbundstrangpressen von Titan‐Aluminium‐Verbindungen

Rod Extrusion of Titanium‐Aluminum Composites The combination of different metals enables the processing of materials with local optimized properties. Thus, the production of metallic composites is associated with high standards in manufacturing technologie. Focus of the following investigations is the rod extrusion process of titanium‐aluminum‐composites. Besides the mechanical properties, the formation of the bonding zone and the mechanisms of adhesion in the bonding zone were investigated. The influence of specimens’ preparation and of different coatings used improve bonding were a matter of particular interest. Whereas coatings of copper or nickel inhibit the formation of a strong bonding due to the formation of oxide layers, sealed titanium cores can reach a mechanical strength of up to 100 MPa after rod extrusion. Compared to other joining technologies, an impairment of the base metal via formation of heat affected zones, pores or grain coarsening does not occur.     

自蔓延反应喷涂技术最新研究及进展

自蔓延反应喷涂技术是近年来产生的一种新的涂层制备技术,它将反应合成技术与喷涂技术相结合,在陶瓷/金属复合涂层制备领域取得了重大突破.围绕自蔓延反应喷涂技术及相关理论研究,综述了该技术的制备方法和最新研究现状,并展望了SHS反应喷涂的研究发展趋势.     

Plasma spray synthesis of TiB2-Fe coatings

A limiting feature of the plasma spray process is the need for the powder to melt during its passage through the plasma flame. It is quite impossible to obtain coatings with materials that are difficult to melt. However, metal borides, particularly titanium boride, are attractive. Because of their high melting point, satisfactory coatings based on these materials have not been achieved.To overcome this problem, a process for making TiB₂-Fe coatings was studied. The TiB₂-based coatings were produced by the reaction of ferrotitanium with boron. The TiB₂ formation was first studied by thermal differential analysis and X-ray diffraction. It was observed that TiB₂ is formed at low temperature by an exothermic reaction. The characteristics of the reaction products obtained at different reaction temperatures are described.Agglomeration techniques were used to prepare the reagents: fine powders of ferrotitanium alloy and boron. TiB₂-Fe coatings were produced by plasma spraying the agglomerated powders. The influence of the plasma spray process parameters and the powder preparation techniques on the coating microstructure is discussed.Thick hard coatings comprising compounds of the reagent materials are produced during spraying by this synergetic process. Such coatings may be suitable for wear resistance applications.     

氟树脂/聚苯硫醚共混改性防腐涂层的研究现状及展望

综述了氟树脂及聚苯硫醚涂料的性能和研究现状,重点介绍了FEP/PPS共混改性梯度涂层技术,分析了表面预处理工艺对该复合涂层的影响,并探讨了其发展趋势.     

颗粒增强金属基复合材料涂层的制备及其特性与应用

针对复合材料涂层的相关问题, 综述了颗粒增强金属基复合材料涂层的制备技术及其特性的研究进展。重点描述了电热爆炸超高速喷涂技术及电刷镀技术制备颗粒增强金属基复合材料涂层的发展现状、涂层组织结构和力学性能研究进展, 概述了颗粒增强金属基复合材料涂层的工程应用领域及其未来发展方向。     

太阳能热发电中储能容器防护涂层的制备与研究

为延长贮有高温金属相变材料容器的使用寿命,在其表面制备了防护涂层.对几种不同配方涂层的抗热震性能、力学性能、耐蚀性能及使用寿命进行了分析,结果表明,涂层的抗热震性能好,涂层与基体结合强度较高,涂层在一定温度限制下具有较好的耐蚀性,而且容器材料的使用寿命也得到很大的延长.     

Electromagnetic welding: an advance in thermoplastics assembly

The bonding process employs the principle of induction to produce rapid, reliable, positive seals on thermoplastics. Almost all thermoplastic materials are capable of being chemically joined to each other as long as the joining materials are compatible with each other in the melt state. A variety of dissimilar materials can also be welded by this process. Mechanical linkage of dissimilar materials can be accomplished via joint designs. Technical information is given about the process and several applications discussed.     

纳米金属/TiO2复合材料的制备及应用研究

综述了制备纳米金属/TiO2复合材料的方法,主要包括溶胶-凝胶法、脉冲电沉积法、离子注入法、光沉积法等,分析了这些方法的制备原理、优缺点及金属对TiO2性能的影响,阐述了纳米金属/TiO2复合材料在催化剂、气敏传感器、光裂解水、锂离子电池等方面的应用研究,并对今后金属/TiO2复合材料的研究方向提出了一些建议.     

金属表面生物陶瓷涂层的研究进展

介绍了目前世界上金属表面生物陶瓷涂层制备的几种主要技术手段,比较分析了各种不同技术手段的优缺点,指出了在金属表面制备生物陶瓷涂层所面临的技术难点,提出了解决这一技术难点思路的几点建议。     

新型聚苯硫醚复合涂层的制备和性能研究

用浸涂法制备了G/MoS2/Ekonol/PES/PPS多元复合涂层,以涂层结合强度为评价标准,采用混料回归实验优化设计了G/MoS2/Ekonol/PES/PPS复合涂层的涂料配方,用拉开法测定复合涂层的结合强度,并对结合表面进行了观察和分析,研究了涂料组成、涂层制备工艺参数和涂层厚度对涂层结合强度的影响。结果表明,用浸涂法能制得力学性能优良的G/MoS2/Ekonol/PES/PPS复合涂层;采用典型配方Ekonol:PES:PPS:G/MoS2:助剂=25:20:45:8:2(质量比)能够得到较大的结合强度。     

Non-contacting seals for critical service process pumps

To improve the quality of life, man has learned to manufacture countless chemicals, pharmaceutical and biotechnological products, petroleum fuels, and numerous metal products. The processing of these products and their by-products has had a major impact on the environment. Tougher air and water quality standards have led to the development of new sealing systems that far exceed performance requirements for emission control. New seal technology has resulted in non-contacting non-leaking seals for conventional pumps handling difficult services. Design and application of this seal technology is presented in this article. Comparison of competing technologies is discussed and life cycle costs are given. Clearly, gas lubricated non-contacting seals for pumps are becoming the choice of sealing technologies for plant operators on difficult services. These systems are proving to be very economical.     

热喷涂纳米涂层制备方法及材料研究现状和展望

综述了热喷涂纳米涂层的制备方法现状及所用材料的发展情况,介绍了溶液等离子喷涂(SPS)、冷气动力喷涂(CGDS)、高速火焰喷涂(HVOF)技术制备纳米涂层的优势、纳米粉末材料的制备方法及发展趋势,指出纳米涂层制备的主要关键在于解决纳米粉末的输送技术和涂层制备过程中抑制纳米颗粒的长大趋势.纳米涂层的研究对推动热喷涂技术应用有着十分重要的作用.     

The use of silane coupling agents in the design of electrically stable interfaces of 6061 T6 aluminum alloy surfaces and epoxy-based electrically conductive adhesives

Electrically conductive interfaces between metal surfaces, including aluminum, are commonly formed by means of bonding with an electrically conductive adhesive. Humid environments induce an increase in electrical resistance between aluminum objects bonded in this manner. However, joints that are electrically stable through stress testing in environments of elevated temperature and humidity (85°C and 80% RH for up to 137.5 h) have been obtained by treating the aluminum surface with a thin layer (less than 50 Å) of an organo-silane coupling agent, that is, a material capable of bonding chemically with the aluminum oxide surface layer and potentially bonding with the polymer binder in the adhesive. The present study shows that besides their traditional use as surface modifiers for adhesion improvement, organo-silanes can act as corrosion inhibitors of aluminum surfaces to stabilize electrical performance. Whereas other treatments used for preparation of metal surfaces for bonding, using electrically-insulating structural adhesives, typically do not ensure reliable electrical performance, minimal and reproducible increase in resistance has been observed for joints prepared using the procedure described here. Application of this method does not require any significant investment in equipment and the surface pretreatment of the metal surface is quite simple.     

Comparison of Tantalum and Hydroxyapatite Coatings on Titanium for Applications in Load Bearing Implants

Over the years hydroxyapatite (HA) coatings have been used to improve biologic properties of Ti‐based load bearing metal implants. However, applicability of HA coated implants is subjected to physical stability of the HA phase and mechanical integrity of the coating‐substrate interface. In this study, we have compared the microstructure and in vitro cell–materials interactions of newly developed laser deposited Ta coatings and radio frequency (RF) induction plasma sprayed HA coatings on Ti substrate. In vitro biocompatibility study, using human osteoblast cell line hFOB, showed equally excellent cellular adherence and growth on Ta and HA coatings. Quantitative assay of cell survivability on these coatings showed that the Ta coatings provide comparable initial cell attachment to that of HA coatings. Microstructural analysis of the coatings showed strong metallurgical bonding without sharp interface between the Ta coating and the Ti substrate, while the interface between HA coating and the Ti substrate was sharp. The interface microstructural features and in vitro cell–materials interactions of Ta coatings on Ti clearly demonstrate their potential to replace HA based coatings for enhanced/early biologic fixation. Other significant benefits of these dense Ta coatings include high toughness, strong bonding with the substrate, and long‐term stability of the interface.