共查询到18条相似文献,搜索用时 93 毫秒
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钛酸锶铅基陶瓷的烧结动力学及显微结构研究 总被引:1,自引:0,他引:1
研究了钛酸锶铅基陶瓷的等温烧结动力学。结果表明,在1130℃等温烧结过程中,致密化与重排过程及扩散控制的溶解-沉淀过程紧密相关。烧结初期的致密化过程主要与粒子的重排有关,烧结中期的致密化机理主要为扩散控制的溶解-沉淀过程。SEM分析表明,烧结初期坯体中局部区域有较多的液相,随着烧结时间的增长,其分布趋于均匀,此时粒子的重排对致密化有较大的贡献。烧结时间为360min时出现了晶粒异常生长。HREM分 相似文献
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NASICON纳米晶固体材料的制备与烧结致密化 总被引:1,自引:0,他引:1
以常规无机试剂和含硅有机试剂为原料,采用溶胶-凝胶过程与压制成型烧结相结合的方法制备了NASICON纳米晶固体材料,利用TG—DTA对前驱凝胶原粉进行了分析测试,结果表明,NASICON相结构的形成温度范围为750-890℃.实验中重点对800-1000℃烧结所得纳米晶材料进行了表征.目的产物的XRD、FT—IR、FE—SEM、IS结果以及阿基米德法致密度测量结果显示,采用合适的烧结温度和周期可以成功制备出具有纳米级颗粒尺寸、良好结晶特性和较高致密度的固体电解质NASICON材料.材料电学特性测试结果表明,所制备的纳米晶固体电解质材料具有良好的离子导电特性和合理的离子传导激活能,其复合电导与温度倒数的Arrhenius图具有很好的线性关系,并且具有较高结晶特性的材料显示出更高的离子电导率. 相似文献
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液相烧结氧化铝陶瓷的致密化机理 总被引:4,自引:0,他引:4
以CaO-MgO-SiO2玻璃为烧结助剂,对液相烧结Al2O3陶瓷的致密化机理进行了研究.研究结果表明,烧结助剂可显著促进Al2O3陶瓷的致密化,其致密度随烧结助剂含量的增加而提高,液相烧结激活能为265kJ/mol,表明扩散控制为其致密化机理. 相似文献
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ITO纳米粉末爆炸压实烧结致密化陶瓷靶材研究 总被引:6,自引:0,他引:6
对ITO商业复合粉末应用爆炸冲击方法压实烧结,并对样品进行了XRD和ESM检测.通过粉末和压实后样品的XRD图及SEM照片的比较,发现在爆炸冲击压实纳米ITO陶瓷粉末时,能够使晶粒度减小,有助于后续烧结密实过程中控制ITO靶材的晶粒度的过分长大;SEM图片显示,在1200℃烧结的靶材微观结构比较均匀.本文探索了纳米ITO粉末冲击压实烧结的微观机理,并与以往人们对粉末的冲击沉能结论进行了比较,得出结论:压实烧结的主要机理是破碎填充效应,使得一部分粉末颗粒表面原子间的距离达到了点阵量级,从而产生键合力;一部分表面原子间的距离达到了一定小的程度,Vander Waals力使其结合. 相似文献
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二氧化锆电泳沉积膜的致密化烧结 总被引:1,自引:0,他引:1
研究了钇稳定二氧化锆微粉在金属陶瓷Ni-8YSZAD THG T AD TP H R JN IYNIIP膜的致密化烧结过程。烧结收缩率△L/L随温度T的增高而增大,在110-1300℃期间,收缩率随温度增国而急剧增加。 相似文献
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316L不锈钢粉末注射成形件的烧结致密化行为 总被引:1,自引:0,他引:1
为了控制粉末注射成形零件的最终尺寸精度和力学性能,对316L不锈钢粉末注射成形件的烧结致密化行为进行了试验研究,分析了烧结温度和升温速率对试件致密化行为以及烧结件力学性能的影响.试验结果表明,致密化过程始于1080℃左右,主要在1200~1300℃的升温过程中快速进行,致密化速率随着升温速率的升高而升高.烧结件的抗拉强度、抗弯强度以及延伸率,不但取决于致密化程度,而且与微观结构有关.分析表明,将基于扩散控制和强度控制的烧结理论结合,可以有效地解释316L不锈钢粉末的致密化行为,需在现有的烧结模型中考虑强度影响因素,才能更真实地模拟烧结过程. 相似文献
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纳米Fe-Cu粉末的制备及其对铁基压坯烧结行为的影响 总被引:2,自引:0,他引:2
以化学共沉淀法制备出纳米Fe-Cu复合粉末并对其性能进行了表征,分别以此纳米Fe-Cu粉末和电解Cu粉与铁粉进行混合获得铁基粉末混合料,成形压坯在H2气氛中不同温度下进行烧结,测定基加入不同形态Cu(合金)粉末铁基烧结坯的烧结性能,结果表明,在相同的Cu添加量及烧结条件下,添加纳米Fe-Cu粉末较加入电解Cu粉于铁基压坯中可以明显地提高压坯烧结后的密度,硬度及强度等性能,而添加纳米Fe-Cu粉末压坯在较低温度下烧结可达到添加电解Cu粉压坯在较高温度下烧结后的性能水平,说明采用纳米Fe-Cu粉末形式向铁基压坯中引入Cu有利于制备高密度,高性能的铁基烧结材料。 相似文献
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Boric acid has been added in 0.1-0.6% range for studying the densification characteristics of solid state sintered barium
hexaferrite. Sintering studies have been carried out at three different temperatures. Physical properties like density and
porosity have been studied for all compositions. The phase identification and microstructural investigation on the fractured
surface have been carried out to understand the effect of sintering aid on the densification characteristics. 相似文献
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AbstractThe retention of nanocrystallinity in dense ceramic materials is still a challenge, even with the application of external pressure during sintering. The compaction behavior of high purity and acetate enriched zinc oxide (ZnO) nano-powders was investigated. It was found that acetate in combination with water plays a key role during the compaction into green bodies at moderate temperatures. Application of constant pressure resulted in a homogeneous green body with superior packing density (86% of theoretical value) at moderate temperature (85 °C) in the presence of water. In contrast, no improvement in density could be achieved if pure ZnO powder was used. This compaction behavior offers superior packing of the particles, resulting in a high relative density of the consolidated compact with negligible coarsening. Dissolution accompanying creep diffusion based matter transport is suggested to strongly support reorientation of ZnO particles towards densities beyond the theoretical limit for packing of ideal monosized spheres. Finally, the sintering trajectory reveals that grain growth is retarded compared to conventional processing up to 90% of theoretical density. Moreover, nearly no radial shrinkage was observed after sinter-forging for bodies performed with this advanced processing method. 相似文献
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Benjamin Dargatz Jesus Gonzalez-Julian Olivier Guillon 《Science and Technology of Advanced Materials》2015,16(2)
The retention of nanocrystallinity in dense ceramic materials is still a challenge, even with the application of external pressure during sintering. The compaction behavior of high purity and acetate enriched zinc oxide (ZnO) nano-powders was investigated. It was found that acetate in combination with water plays a key role during the compaction into green bodies at moderate temperatures. Application of constant pressure resulted in a homogeneous green body with superior packing density (86% of theoretical value) at moderate temperature (85 °C) in the presence of water. In contrast, no improvement in density could be achieved if pure ZnO powder was used. This compaction behavior offers superior packing of the particles, resulting in a high relative density of the consolidated compact with negligible coarsening. Dissolution accompanying creep diffusion based matter transport is suggested to strongly support reorientation of ZnO particles towards densities beyond the theoretical limit for packing of ideal monosized spheres. Finally, the sintering trajectory reveals that grain growth is retarded compared to conventional processing up to 90% of theoretical density. Moreover, nearly no radial shrinkage was observed after sinter-forging for bodies performed with this advanced processing method. 相似文献
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采用改进的Sol-gel工艺和传统烧结技术制备了晶粒尺寸在0.15~10μm的Ba0.6Sr0.4TiO3(BST)陶瓷,观察了样品的显微结构,并对样品的介电性能进行了测试,分析了晶粒尺寸对材料介电性能的影响.实验结果表明:改进的Sol-gel工艺和两步烧结法可以有效地控制Ba0.6Sr0.4TiO3(BST)陶瓷的晶粒尺寸.晶粒尺寸的降低,材料的介电常数也随之下降,介电峰呈现明显的铁电-顺电弥散相变;但当陶瓷的晶粒尺寸<1 μm,介电常数出现峰值,铁电相变温区变窄. 相似文献
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AbstractHigh magnetic field was applied to fabricate novel lead-free piezoelectric ceramics with a textured structure. A compact of crystallographically oriented grains was prepared by dry forming in a high magnetic field from a mixed slurry of bismuth titanate and barium titanate powders. Bismuth titanate particles with a size of about 1 μ m were used as the host material. In the forming process, the slurry was poured into a mold and set in a magnetic field of 10 T until completely dried. Bismuth titanate particles were highly oriented in the slurry under the magnetic field. The dried powder compact consisted of highly oriented bismuth titanate particles and randomly oriented barium titanate particles. Barium bismuth titanate ceramics with a- and b-axis orientations were successfully produced from the dried compact by sintering at temperatures above 1100 ° C. 相似文献
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Satoshi Tanaka Yusuke Tomita Ryoichi Furushima Hiroyuki Shimizu Yutaka Doshida Keizo Uematsu 《Science and Technology of Advanced Materials》2009,10(1)
High magnetic field was applied to fabricate novel lead-free piezoelectric ceramics with a textured structure. A compact of crystallographically oriented grains was prepared by dry forming in a high magnetic field from a mixed slurry of bismuth titanate and barium titanate powders. Bismuth titanate particles with a size of about 1 μ m were used as the host material. In the forming process, the slurry was poured into a mold and set in a magnetic field of 10 T until completely dried. Bismuth titanate particles were highly oriented in the slurry under the magnetic field. The dried powder compact consisted of highly oriented bismuth titanate particles and randomly oriented barium titanate particles. Barium bismuth titanate ceramics with a- and b-axis orientations were successfully produced from the dried compact by sintering at temperatures above 1100 ° C. 相似文献