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反应合成是陶瓷材料的重要制备工艺之一,在制备块体陶瓷、纤维增强复合材料基体、复合材料的陶瓷防护涂层等方面具有广泛的应用。本文简要介绍了作者多年来在反应合成复相陶瓷方面的研究结果,包括硼化钛体系、硼化锆体系、碳化物体系、氮化硼体系以及最近发展起来的高熵陶瓷体系。不同的反应体系包含有化学性质完全不同的反应物、化学反应中可能存在较大的放热现象、反应物存在分解后再反应等中间过程、产物中可能存在气相副产物等不同特征,后续致密化过程与前期反应过程的控制具有复杂多样的密切关系,所以深入研究前期反应过程和后期致密化及显微结构形成机理对反应合成具备特殊显微结构和性能的陶瓷材料具有重要的意义。高温化学反应不仅可以用于合成陶瓷材料,在采用非反应合成的常规工艺制备陶瓷材料特别是非氧化物陶瓷的过程中也普遍存在,了解这些化学反应进行的条件有利于设计合理的工艺制度,从而获得性能优越的材料。 相似文献
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陶瓷材料抗热震性的研究进展 总被引:7,自引:0,他引:7
阐明了陶瓷材料抗热震性研究的重要意义,系统总结了陶瓷材料抗热震的评价理论、热震断裂机制和设计高抗热震陶瓷材料的新近研究成果,并基于理论提出了改善陶瓷材料抗热震性的策略。即从控制显微结构出发,增加材料的韧性和热传导性、降低材料的弹性模量和线胀系数,为制作高抗热震陶瓷材料提供了可借鉴的工程技术途径。 相似文献
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研究了不同TiB2含量的Al2O3/TiO2陶瓷材料的高温氧化行为。用XRD和SEM分析了材料氧化后的相组成及显微结构。探讨了该材料的氧化机理和氧化膜的破坏方式。结果表明:不同TiB2含量的Al2O3/TiB2陶瓷材料在1400℃空气中氧化30h的氧化增重符合抛物线规律;随TiB2含量的增加,材料的氧活化能降低,氧化后的强度损失率增大。 相似文献
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α—Al2O3/SiC,莫来石/SiC和ZrO2/SiC二元复合材料的显微结构 总被引:1,自引:0,他引:1
用热压法制备了氧化物(刚玉、莫来石、氧化锆)与非氧化物(碳化硅)的二元复合陶瓷材料。采用TEM和HREM等手段对上述材料的显微结构和晶界附近的微区成分进行了研究,确定氧化物与碳化硅相可以直接结合并形成一定厚度的互扩散层。 相似文献
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研究了不同TiB2含量的Al_2O_3/TiB_2陶瓷材料的高温氧化行为。用XRD和SEM分析了材料氧化后的相组成及显微结构。探讨了该材料的氧化机理和氧化膜的破坏方式。结果表明:不同TiB2含量的Al2O3/TiB2陶瓷材料在1400℃空气中氧化30h的氧化增重符合抛物线规律;随TiB2含量的增加,材料的氧化活化能降低,氧化后的强度损失率增大。 相似文献
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Si3N4—SiC复相陶瓷增强颗粒尺寸效应 总被引:1,自引:0,他引:1
本文采用不同颗料尺寸的SiC粉体与Si3N4复合,采有热压烧结工艺制备了Si3N4-SiC复相陶瓷材料。研究了不同SiC颗粒尺寸、含量对复合材料致密化、显微结构和力学性能的影响。结果表明,晶粒尺寸越小强度越高,硬度也越大,但断裂韧性随粒径的变化不大。验证了颗粒复合的均匀分布模型和增强分布模型。 相似文献
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The objective of this paper was to improve the accuracy of semi-empirical method used to design ceramic cutting tool materials. The mechanical properties were predicted by employing finite element model of material microstructure, so as to design microstructure and prepare new ceramic materials. Based on the Voronoi and randomness method, the microstructure model representing the complexity and randomness of micro-nano-composite ceramic material microstructure was established. Combining the representative volume element (RVE) of ceramic material microstructure with mechanical tests, the simulations of mechanical tests were conducted to acquire the flexure strength, fracture toughness and hardness of materials. The microstructure models with various parameters were designed and the material properties were predicted to determine the optimal microstructure parameters. Then, The ceramic cutting tool materials possessing the optimal microstructure parameters were developed for machining ultra-high strength steels. The results showed that the mechanical properties of ceramic materials first improved and then declined as the nano-scale TiC volume fraction increased. To obtain the best comprehensive mechanical properties, the contents of micro-scale TiN, TiC and nano-scale TiC were set as 20%, 10% and 10%, respectively. The prepared ceramic materials possessed the flexure strength of 881.4 MPa, the fracture toughness of 7.8 MPa m1/2, and the Vickers hardness of 20.8 GPa. This research is beneficial to the development of cutting tool design theory and the improvement of the tool life. 相似文献
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考察了纳米SiC -Al2 O3/TiC多相陶瓷复合材料的断裂方式 .由于纳米SiC的加入 ,材料以穿晶断裂为主 .通过透射电镜观察 ,研究了纳米陶瓷复合材料中纳米SiC的分布 ,证明所制备的材料主要为晶内型纳米复合陶瓷 .在纳米SiC -Al2 O3/TiC多相陶瓷复合材料中 ,少量纳米SiC位于基体晶粒间 ,大多数纳米SiC位于基体晶粒内 ,而且纳米SiC的加入细化了基体的晶粒 .通过高分辨透射电镜观察 ,研究了纳米SiC -Al2 O3/TiC多相陶瓷复合材料中 ,纳米SiC与基体间界面结合状态 ,发现在两颗粒间的晶界几乎没有玻璃相 ,证明纳米陶瓷复合材料中晶界得到了加强 ,有利于材料力学性能的提高 .另外研究了裂纹在材料中的扩展行为 ,结果表明 ,纳米粒子对裂纹的扩展起到偏折和钉扎作用 相似文献
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从原料选择、配方设计、工艺路线等方面 ,详细介绍了清香杀虫剂用陶瓷容器的研制情况 ,并深入分析了陶质坯体中铁的呈色规律和红泥陶产品的微观结构 相似文献
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金属表面化学反应陶瓷涂层的研究 总被引:12,自引:0,他引:12
采用化学反应法,在普通碳素钢上涂覆一层的均匀致密的陶瓷涂层,经微观结构分析和性能检测表明:涂层为复相陶瓷结构,主要相有Al2O3,TiB2,FeAl2O4等。涂层与基体的结合强度较高;涂层的耐腐蚀性优异,抗热震性较好。 相似文献
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《Ceramics International》2022,48(22):33245-33255
As a surface strengthening and surface modification technology of materials, liquid thermal spray technology has been used in many fields, such as wear and friction reduction, corrosion resistance, and high-temperature oxidation resistance. This article reviews the progress of liquid thermal sprayed coating in wear resistance as well as friction reduction in recent years. The influences of microstructure, composition, phase structure and mechanical properties on the tribological properties of typical coatings (including ceramic coatings and multiphase composite coatings) are investigated. The tribological properties of the coating are determined by the coating characteristics (including microstructure, porosity, mechanical properties, etc.) and the service conditions (working temperature, lubrication state, etc.). Typical ceramic wear-resistant coatings include Al2O3, YSZ, HA coatings, etc. The tribological properties of the coating can be significantly improved through process optimization and heat treatment. The comparison of nanostructured and microstructured ceramic-based coating reveals that nanostructured coating reduces wear by absorbing stress. The interaction between different constituent phases improves wear resistance and reduces wear in composite coatings. Finally, various challenges faced by liquid thermal spray are pointed out, and future research focuses are proposed. 相似文献
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Enrico Traversa 《Journal of the American Ceramic Society》1995,78(10):2625-2632
Recently, the search for novel functions has received increasing attention in the field of materials. Outstanding possibilities for innovative applications are given by electroceramics. One of the fields which may be improved by a different use of functional ceramics is that of chemical sensors. In fact, the materials conventionally used in this field show problems still to be solved, such as insufficient gas selectivity, inability to detect very low gas concentrations, and changes in sensing properties caused by surface contamination. One possible solution to these problems is the design of materials with novel detection mechanisms. The design of innovative properties may be achieved by integration or hybridization of materials with different properties. In this paper, examples of multiphase materials for humidity and gas sensors are reported, i.e., La2 CuO4 /ZnO p-n heterocontacts, Au/ZnO Schottky barriers, and sol-gel processed thin films of TiO2 with 10 at. % of K, based, respectively, on the interaction of p -type/ n -type semiconductors, metal/ceramic, and conductor/insulator. 相似文献