BAS系微晶玻璃抗氧化涂层的制备与性能

利用2层不同软化温度和不同热膨胀系数的BaO-Al₂O₃-SiO₂(BAS)系微晶玻璃, 采用浆料涂覆—浸渍—多层共烧的方法制备了2种双层同组分和1种双层不同组分的C_f/SiC复合材料抗氧化涂层。3种结构的BAS系微晶玻璃涂层完整、 无明显缺陷, 涂层与C_f/SiC复合材料的结合状态良好, 有助于提高C_f/SiC复合材料的抗氧化性能。双层不同组分的BAS系微晶玻璃涂层在1200~1350 ℃范围内对提高C_f/SiC复合材料抗氧化性能的作用显著, 失重速率和失重量均明显减小。与未包覆涂层的复合材料相比, 包覆双层不同组分涂层的复合材料经历600次(每次保温10 min)热冲击后的失重降低了1/2~2/3, 保留的强度提高了7~15倍。      

纤维补强微晶玻璃复合材料性能设计

在 Li_2O-Al_2O_3-SiO_2和 Li_2O-MgO-CaO-Al_2O_3-SiO_2系统中,对具有不同热膨胀系数(α)的烧结微晶玻璃基体作了研究。一些微晶玻璃基体能够同补强纤维结合得很好,适用于制备成碳纤维或 SiC纤维补强微晶玻璃复合材料。当微晶玻璃基体的α调节到比加入纤维的α稍低的范围内,复合材料的抗折强度和断裂韧性可达到满意的水平,F_b 为584MPa,K_(1c)为16.5MPa·m~(1/2)。实验结果作为纤维补强微晶玻璃复合材料性能设计原则,在上述系统中得到了验证。文中对微晶玻璃这类多相复合体热膨胀系数设计的理论依据作了讨论。     

SiC纤维/LAS复合材料的TG-DTA-MS研究

本文首次用TG-DTA-MS联用技术对SiC纤维/LAS微晶玻璃复合材料的热分解过程、机制及其与晶化的关系进行了研究。提出了该复合材料界面形成碳层的热力学和质谱分析判别依据,并对晶化前后的复合材料的热分解行为作了实验对比和理论分析。      

La2O3在MgO-Al2O3-SiO2-TiO2微晶玻璃中的作用

在ＭｇＯ－Ａｌ_２Ｏ_３－ＳｉＯ_２－ＴｉＯ_２玻璃中添加不同数量的氧化镧,采用差热分析、Ｘ射线衍射及电子显微镜等技术研究了氧化镧对玻璃析晶过程与力学性能的影响．氧化镧的加入使玻璃中析出α－堇青石相的温度降低;同时避免了高膨胀方石英相的析出．随着氧化镧加入量的增加,玻璃整体析晶能力下降,微晶玻璃中晶相含量减少,晶粒尺寸增大,微晶玻璃的弹性模量与硬度减小,断裂韧性增加,体现出大尺寸长柱状金红石晶粒的增韧作用．     

A/W生物微晶玻璃材料的研究进展

生物活性玻璃陶瓷材料由于能够与活体组织自发产生紧密的化学键合而成为骨修复材料中的重要分支,其中A/W生物微晶玻璃更是由于在保持良好生物活性的基础上,力学性能接近甚至超过自然骨而作为承重的生物活性材料应用于临床.系统介绍了A/W生物微晶玻璃的制备方法、生物活性和力学性能,并展望了A/W生物微晶玻璃今后的研究发展方向.     

微晶玻璃的摩擦学特性研究进展

微晶玻璃及其复合材料在各种摩擦条件下,尤其是干摩擦下优良的摩擦学特性赋予了材料很大的研究开发潜力.本文综述了微晶玻璃的摩擦磨损行为与机制,并提出了微晶玻璃在摩擦学领域需要进一步探讨的问题.     

铝酸酯偶联剂表面改性微晶白云母/PVC复合材料的制备及力学性能

以中国川西地区发现的一种新型矿物资源微晶白云母为原料,以铝酸酯偶联剂F-1为改性剂,对微晶白云母进行改性研究,并将表面改性后的微晶白云母加入聚氯乙烯(PVC)中制得微晶白云母/PVC复合材料。测试了改性粉体与石蜡体系的黏度及复合材料的力学性能,并采用扫描电子显微镜表征了其微观结构。结果表明,铝酸酯偶联剂F-1能有效改善微晶白云母表面与有机物质的界面结合,并且将经铝酸酯偶联剂F-1改性的微晶白云母加入PVC基体中能提高微晶白云母/PVC复合材料的力学性能,当铝酸酯偶联剂的用量为1.0%(质量分数,下同)、微晶白云母用量为15%时,微晶白云母/PVC复合材料的力学性能最好。     

Ce-YAG微晶玻璃的制备及其发光性能

采用高温固相熔融法在弱还原气氛下制备了Ce3+离子掺杂的Y2O3-A12O3-SiO2(SAY)系基础玻璃,并在1250℃~1300℃热处理一定时间制备了晶相为YAG的黄色微晶玻璃。通过XRD、SEM研究了微晶玻璃的结构及相组成;激发和发射光谱分析了Ce3+离子在玻璃及微晶玻璃不同基质中的发光特性,以及Al2O3/Y2O3摩尔比对微晶玻璃样品发光性能的影响。结果表明:基础玻璃经热处理能得到Ce-YAG微晶玻璃,晶粒大小在80~120nm范围内,晶粒发育良好。该微晶玻璃样品能被450nm有效激发,并在530nm处有宽带发射峰,归属于Ce3+的5d-4f(2F2/7)。该微晶玻璃在LED照明领域中有很大的应用开发价值。Al2O3和Y2O3的摩尔含量变化对微晶玻璃发光性能有较大影响,在Al2O3/Y2O3的摩尔比为1.5时,样品的发光性能最佳。     

玻璃陶瓷基复合材料制造工艺的探讨

本文研究了碳纤维增强微晶玻璃复合材计的制造工艺。基体采用三种材料:金云母可切削微晶玻璃,锂云母和LAS微晶玻璃。在实验室内采用粉末烧结法研制出这种材料样品。本文在成型工艺上作了改进,对关键工艺——粘接成型引入溶胶凝胶法。本文探讨了适合复合材料制造工艺的溶胶配方和工艺,改进了其使用方法。本文还利用物化检测手段对这三种微晶玻璃复合材料进行了分析对比,其性能仍保持了原基体材料的优良性能。     

离子交换法制备金属纳米颗粒-玻璃复合材料的研究进展

如何制备出具有优良光学三阶非线性性能的金属纳米颗粒-玻璃复合材料已经成为目前研究的热点.着重介绍了离子交换法结合后续处理的方法制备金属纳米颗粒-玻璃复合材料的最新研究进展,并结合对文献资料的分析,指出了今后的研究方向和发展前景.     

纤维涂层对复合材料力学性能的影响

对于ＳｉＣ纤维／ＭＡＳ微晶玻璃复合系统，发现在烧结温度下，纤维和基体之间有较严重的化学反应发生，界面结合强，力学性能较差．通过对ＮｉｃａｌｏｎＳｉＣ纤维加涂层，发现Ｎｂ２Ｏ５和ｃ涂层对复合材料的界面结合改善不大，而ＬＣＡＳ晶玻璃涂层能使纤维和基体间的界面结合明显减弱，力学性能大幅度提高，室温抗折强度和断裂韧性分别达３２７ＭＰａ和１３．９ＭＰａ·ｍ１／２．     

Fibre-matrix bond strength studies of glass,ceramic, and metal matrix composites

An indentation test technique for compressively loading the ends of individual fibres to produce debonding has been applied to metal, glass, and glass-ceramic matrix composites; bond strength values at debond initiation are calculated using a finite-element model. Results are correlated with composite longitudinal and interlaminar shear behaviour for carbon and Nicalon fibre-reinforced glasses and glass-ceramics including the effects of matrix modifications, processing conditions, and high-temperature oxidation embrittlement. The data indicate that significant bonding to improve off-axis and shear properties can be tolerated before the longitudinal behaviour becomes brittle. Residual stress and other mechanical bonding effects are important, but improved analyses and multiaxial interfacial failure criteria are needed to adequately interpret bond strength data in terms of composite performance.     

Preparation,properties and chemistry of glass- and glass-ceramic-to-metal seals and coatings

An overview is given outlining the materials and technologies that have been employed in the preparation of glass- and glass-ceramic-to-metal seals and coatings. Metal/non-metal bonding theories are summarized, and the conditions required for the formation of strong chemical bonding are described and discussed. Particular reference is given to the interfacial chemistry involved for individual glass/metal and glass-ceramic/metal combinations. The major factors responsible for the preparation of high-quality seals and coatings, free from porosity and other undesirable defects, are also outlined and discussed. In addition, a number of applications for seals and coatings are briefly described.     

Microstructural characterisation of a glass and a glass-ceramic obtained from municipal incinerator fly ash

Scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy and X-ray diffraction (XRD) analyses were used to characterise the microstructure and chemical composition of a glass and a glass-ceramic material obtained from incinerator filter fly ash. Although the as-quenched material (vitrified fly ash) was amorphous under the detection limits of XRD, a dispersion of droplets indicating glass-in-glass phase separation was observed. In the glass-ceramic material (crystallised vitrified fly ash), crystals belonging to the pyroxene group and spinels were identified. The microstructure of the glass-ceramic consisted of crystals embedded in an amorphous glassy phase. The crystalline phases contain a higher amount of metallic elements (e.g. Al, Cr, Fe, Ni and Zn and most probably also other heavy metals) than the residual glassy phase. A change of composition of the residual glass phase in the glass-ceramic product, in comparison with the parent glass, is considered to explain, in comparative terms, the higher toxic potential of the glass-ceramic over the glass. The present results demonstrate that for an accurate assessment of the correlation between toxicity, release of hazardous compounds and microstructure, high-resolution characterisation techniques must be employed. In this context, the effect of crystallisation on the chemical durability of the products remains as an important area for further research.     

硅酸盐玻璃/铝合金异种材料连接综述

硅酸盐玻璃/铝合金异种金属连接接头兼具优良的功能性及稳定的力学性能,在航空航天、电子通讯等领域具有良好的应用前景.本文对玻璃与铝合金的连接性进行了分析,总结并综述了目前硅酸盐玻璃和铝合金在胶接、半固态连接和焊接方面的研究成果.另外,详细分析了硅酸盐玻璃与铝合金的连接机理,并对玻璃和铝合金异种材料连接的未来研究和发展进行了展望.一种基于钎焊并与辅助外场结合的复合连接技术可能是实现硅酸盐玻璃/铝合金异种材料优质连接的未来研究方向之一.     

Mechanical properties of molybdenum-sealing glass-ceramics

Elastic constants, thermal expansion, strength, and fracture toughness were determined for a glass-ceramic which bonds to molybdenum and matches its thermal expansion. Mechanical properties of the glass-ceramic were related to microstructure following two different crystallization treatments and moderate changes in composition. Crystallization increases the toughness and modulus of the parent glass even while the residual glass properties decline. Fracture toughness of the composite is shown to depend primarily upon properties of the separate phases; however, internal stresses are shown to decrease toughness without decreasing Young's modulus.     

Glass-ceramic-metal composites for making graded seals in prosthetic devices

The possibility of using glass-ceramic-metal composites as graded seals between dense cores of prostheses and a porous glass-ceramic coating, which would promote a direct bond with the bone has been investigated, particularly with respect to thermal and elastic properties. Before binding them to a core, bulk composite materials have been prepared in order to study their properties.These materials have been obtained from powdered mixtures of a calcium alumino-phosphate glass (CAP) with increasing volume fractions (3.5–50%) of various metals or alloys: titanium, 316 L stainless steel, cobalt-chromium 788 alloy. They have been synthesized by hot pressing immediately followed by a heat treatment to obtain ceramicization of the glass matrix.Elastic and thermal properties have been determined. The values of elastic moduli and average linear thermal expansion coefficients lie within those of glass-ceramic CAP and those of the corresponding metal. Mechanical properties have been also measured. The material can withstand about four times the body weight when materials are bound to a more rigid metal or alloy.     

Influence of Surface Modification on Tribo-Performance of Hybrid Glass/PTFE Fabric Composite with Phenolic Resin Binder

The fabric/phenolic composites with the pure and silanized hybrid glass/PTFE fabric were prepared by dip-coating of the hybrid glass/PTFE fabrics in a phenolic resin. The friction and wear performances of the resulting fabric composites were evaluated using pin-on-disc wear tester. The composition change of the glass fabric in hybrid glass/PTFE fabric after silanization was analyzed by FTIR spectroscopy. The morphologies of the composite structures and the worn surfaces of the composites were analyzed by means of scanning electron microscopy (SEM). The results show that the fabric/phenolic composite with the β-aminoethyltrimethoxylsilane silanized hybrid glass/PTFE fabric can obtain the highest load-carrying capacity and the best wear-resistance, followed by the composite with γ-glycidoxypropyltrimethoxysilane silanized hybrid glass/PTFE fabric. Chemical reactions have achieved as the hybrid glass/PTFE fabric was silanized with β-aminoethyltrimethoxyl silane or γ-glycidoxypropyltrimethoxy silane, which contribute to strengthen the bonding strength between the fabric and the adhesive and hence to improve the tribological properties of the hybrid glass/PTFE fabric composites.     

Improvement of Joint Strength of SiCp/Al Metal Matrix Composite in Transient Liquid Phase Bonding Using Cu/Ni/Cu Film Interlayer

The compact oxide on the surface of SiCp/Al metal matrix composite （SiCp/Al MMC） greatly depends on the property of the joint. Inlaid sputtering target was applied to etch the oxide completely on the bonding surface of SiCp/Al MMC by plasma erosion. Cu/Ni/Cu film of 5μm in thickness was prepared by magnetron sputtering method on the clean bonding surface in the same vacuum chamber, which was acted as an interlayer in transient liquid phase （TLP） bonding process. Compared with the same thickness of single Cu foil and Ni foil interlayer, the shear strength of 200 MPa was obtained using Cu/Ni/Cu film interlayer during TLP bonding, which was 89.7% that of base metal. In addition, homogenization of the bonding region and no particle segregation in interfacial region were found by analysis of the joint microstructure. Scanning electron microscopy （SEM） was used to observe the micrograph of the joint interface. The result shows that a homogenous microstructure of joint was achieved, which is similar with that of based metal.     

T2纯铜/2024铝合金爆炸焊接接头界面结构及性能

为研究铜铝异种金属爆炸焊接头界面形成机理,采用爆炸焊对T2纯铜和2024铝合金进行了焊接.通过光学显微镜、扫描电镜、X射线衍射、万能材料试验机和纳米压痕仪,对T2/2024复合板结合界面的显微组织、成分分布和力学性能进行了测试分析.结果表明:T2/2024合金爆炸复合板结合界面呈波状结合,结合界面主要由平直界面、波状界面和局部熔化层界面构成;靠近结合界面处,基体金属发生塑性变形,晶粒细化;反应层主要成分为AlCu和Al_2Cu的混合物.复合板拉剪试验表明,T2/2024合金爆炸复合板平均结合强度为67 MPa,纳米压痕测试反应层平均硬度可达8 GPa.