CuO+TiO2复相添加剂对氧化铝陶瓷烧结性能和显微结构的影响及其烧结动力学分析

研究了CuO＋TiO2复相添加剂对氧化铝陶瓷烧结性能，显微结构的影响以及形成液相时氧化铝陶瓷烧结动力学。添加剂的加入极大的促进了氧化铝陶瓷的烧结。当CuO与TiO2质量比为1：2的时候，氧化铝样品致密度最高。液相含量对致密度有明显影响，液相含量越高，烧结速率越快。添加剂的存在使氧化铝晶粒细化，晶粒形貌为等轴状。利用等温烧结的实验方法研究了烧结动力学，结果表明，是由氧离子和铝离子的扩散作用控制了烧结过程。     

放电等离子烧结AlN陶瓷

研究了放电等离子烧结氮化铝陶瓷的过程。通过对比掺与不掺烧结助剂的氮化铝陶瓷的两种烧结过程，指出了烧结助剂在放电等离子烧结氮化铝陶瓷过程中的作用。利用放电等离子烧结技术烧结氮化铝，在加Y2O3-Li2O-CaF2作为烧结助剂，1700℃的烧结温度，25MPa的压力下，仅保温5min，得到相对密度为97．3％的AlN陶瓷。SEM表明试样内部晶粒细小，结构均匀。实验表明：放电等离子烧结技术可实现快速烧结。     

无压烧结氮化硅陶瓷的研究

本文选用MgO-Al2O3作为复合添加剂，采用无压烧结，设计Si3N4-MgO-Al2O3系烧结体、Si3N4-SiC-MgO-Al2O3系烧结体，研究各种配方在不同忝型压力不同烧结条件下烧结体的性能，测定室温抗折强度、体积密度、体积变化和气孔率，通过X射线衍射分析鉴定烧结体的物相结构，从而确定了最佳工工艺范围。     

脉冲电流烧结的现状与展望

脉冲电流烧结(Pulse Electric Current Sintering，PECS)技术是近十年发展起来的一种新型特殊的快速烧结技术。它具有升温速度快、烧结时间短、有利于控制烧结体的细微结构等特点。近几年来在纳米材料、复合材料等的制备中显示了极大的优越性，得到了材科学界和产业界的瞩目。本文介绍了脉冲电流烧结的特征和研究现状，并展望了在今后新材料开发中的应用前景。     

烧成对钛酸锶压敏陶瓷电学性能的影响

本文研究了烧结助剂、烧结温度和烧结气氛对SrTiO3压敏陶瓷材料性能的影响。结果表明：在烧结过程中使用Al2O3和H2SiO3作烧结助剂比用Li2CO3和H2SiO3效果更好；在1420℃烧结的样品与1400℃及1440℃相比，具有较好的综合电性能；烧结过程中，除要保证还原性气氛外，还要有一定的氧分压。     

液相烧结氧化铝陶瓷及其烧结动力学分析

研究了CuO TiO2复相添加剂对Al2O3陶瓷烧结性能、显微结构的影响以及添加剂形成液相时Al2O3陶瓷的烧结动力学.结果显示:添加剂的加入明显地促进了Al2O3陶瓷的烧结致密度.添加剂含量对致密有明显影响,含量越高,烧结速率越快.当添加剂(CuO TiO2)为2%(质量分数),CuO/TiO2质量比为1/2时,Al2O3样品致密度最高.添加剂的存在使Al2O3晶粒发生较快生长,晶粒形貌为等轴状.通过等温烧结动力学,确定掺杂Al2O3陶瓷烧结激活能为25.2kJ/mol,表明可能是氧离子和铝离子在液相中的扩散作用控制了烧结过程.     

陶瓷烧结新技术—微波烧结

本文综述了微波烧结陶瓷材料这一新技术在国内外的研究，应用和进展，并介绍和指出了微波烧结的原理，特点及其未来展望。     

毫米波烧结对纯钛酸钡陶瓷介电性能的影响

利用34.5GHz回旋管毫米波烧结和常规烧结分别制备了纯钛酸钡陶瓷材料，分析和比较了2种烧结方法制备的纯钛酸钡陶瓷材料的介电性能，讨论了毫米波烧结对纯钛酸钡陶瓷材料显微组织和介电性能的影响。结果表明：与常规烧结相比，毫米波烧结过程具有更高的固态扩散速率,毫米波烧结陶瓷样品中出现晶粒异常长大的烧结温度更低；毫米波烧结能够显著降低烧结温度；960℃烧结15min的毫米波烧结样品的相对密度为96.6％，而经960℃常规烧结60min的样品的相对密度仅为54.8％。900℃毫米波烧结15min的样品与1220℃常规烧结15min样品的相对密度相近(分别为88.7％和89.6％)，而前者的介电常数(4224)远高于后者(3655)。     

TiSi_2改善TiB_2陶瓷烧结性能的研究进展

本文介绍了硼化钛陶瓷的性能与应用,重点介绍了不同的烧结方法、不同的烧结助剂对硼化钛陶瓷烧结性能的影响,在对TiSi2材料性能特点分析的同时,阐述了TiSi2作为烧结助剂改善硼化钛陶瓷烧结性能与抗氧化性能的依据,指出了开展TiSi2改善TiB2陶瓷的烧结性能与抗氧化性能的研究亟待解决的问题,提供了一条改善TiB2陶瓷烧结性能的新途径,具有理论意义与应用价值。     

多种外加剂对红柱石制品烧结性能影响的研究

研究了多种外加剂对红柱石原料烧结性能的影响，分析了其作用机理。结果表明：加入氧化镁可明显促进红柱石的烧结，在高温阶段其作用更加明显，但其质量分数必须严格控制，不宜超过2％。添加氧化钛也可促进红柱石的烧结，其质量分数应该控制在4％以内。而添加氧化铬和氧化锆则不利于红柱石的烧结。     

Densification behavior and microstructure development in TiB2 ceramics doped with h-BN

This paper aims to study the impacts of h-BN additive on the microstructural features and sintering behavior of TiB₂. For this objective, two different samples of monolithic TiB₂ and TiB₂-5 wt% h-BN were fabricated using spark plasma sintering (SPS) technique at 1900 °C. An external pressure of 40 MPa was exerted to the specimens during the sintering, and they were maintained at the maximum sintering temperature for 7 min. The characterization of as-fabricated ceramics was carried out using thermodynamical investigations, field emission SEM, and X-ray diffractometer. The thermodynamical and XRD studies revealed that the sintering process was non-reactive for both samples. However, introducing h-BN noticeably promoted the sinterability of TiB₂ through activating the liquid phase sintering mechanism, and a near-fully dense composite was attained. The fractographical assessment manifested that the intergranular fracture was the dominant type in both monolithic and h-BN doped specimens. Finally, the quantitative image analysis indicated the role of h-BN in refining the microstructure of the doped TiB₂ ceramic.     

纳米TiO2陶瓷无压烧结的主烧结曲线

采用纳米金红石相TiO2粉末在空气中进行烧结,用热膨胀仪记录恒定加热速率条件下的烧结过程,测量了烧结体密度,根据烧结3个阶段的全期烧结模型(combined-stage sintering model),建立TiO2主烧结曲线(master sintering curve).纳米TiO2主烧结曲线对烧结路径不敏感,烧结体的相对密度仅是时间和温度的函数,利用主烧结曲线得到的相对密度和Archimedes法实测的密度吻合,证明了主烧结曲线的有效性;根据纳米金红石的主烧结曲线,得到其在空气中的烧结激活能为105 kJ/mol;可以预测烧结收缩量和最终相对密度,准确描述烧结全程的烧结行为.     

先进陶瓷材料快速烧结技术发展现状及趋势

快速烧结技术在节省时间和能源方面的巨大优势使其成为一直以来的研究热点。近几十年来,快速烧结技术(如火花等离子烧结、闪电烧结、选区激光烧结、感应烧结、微波烧结和传统烧结装置中的快速烧结等)的发展,使陶瓷材料的快速烧结成为可能。本文综述了近20年来先进陶瓷领域中的快速烧结技术和烧结机理,并对火花等离子烧结中直流脉冲电流和机械压力对微观结构、材料性能和烧结机理的影响进行了深入分析和总结。同时指出,快速烧结技术今后的发展一方面是对烧结机理的进一步研究并应用到先进陶瓷材料的制备中,另一方面是解决快速烧结技术工业化生产中大尺寸、大批量生产的难题。     

High density nano-grained Gd2Zr2O7 ceramic prepared by combined cold and microwave sintering

In this study, nano-grained Gd₂Zr₂O₇ (NGZO) ceramic with a high relative density was prepared by a novel cold sintering process (CSP) assisted by microwave sintering (CSP-MS). The CSP with water as the liquid phase at 280 °C yielded nano-grained ceramic with a relative density of 71.5%. NGZO with a high relative density of 97.1% and average grain size of 73 nm was obtained by subsequent microwave sintering of the cold-sintered sample at 1300 °C. Therefore, CSP-MS is feasible in preparing dense NGZO ceramics with small grain sizes at relatively low sintering temperatures.     

微波烧结ZTA陶瓷的影响因素

通过改进混合加热模式,实现了ZTA陶瓷微波烧结。材料的类型及配比直接影响微波烧结的升温速率;输入功率的提高有助于提高烧结速率;辅助加热体的老化现象降低微波烧结速率;微波烧结过程中应避免出现热剧变现象。     

Pressureless sintering of transparent AlON ceramic with assimilable γ-Al2O3 as sintering promoting additives

Transparent aluminum oxynitride (AlON) ceramic was successfully fabricated without doping sintering additive by the pressureless sintering method. Γ-Al₂O₃ nano-powder that can be assimilated by the AlON matrix was used for promoting the densification of AlON during the sintering. The sintering behavior of AlON and the effects of γ-Al₂O₃ nano-powder on the phase, hardness, and transmittance of AlON have been investigated in detail. The mechanisms of γ-Al₂O₃ nano-powder on the AlON green body modifying and the sintering promoting are revealed. The transmittance of the AlON ceramic is dramatically enhanced by doping γ-Al₂O₃ nano-powder and the 2 mm thick sample doped with 2.5 wt% γ-Al₂O₃ nano-powder shows an inline transmittance above 81% at 1500 nm.     

高纯超细氧化铝粉的常压烧结与高压烧结

以高纯超细α-Al₂O₃粉为原料,采用常压、高压烧结制备了高纯Al₂O₃陶瓷。研究表明,在乙醇溶剂中高速球磨可显著降低Al₂O₃粉料的平均颗粒尺寸,提高粉料的比表面积与烧结活性;在4.5 GPa、1230℃高压烧结30 min,制备了相对密度达98.71%的无烧结助剂掺杂的Al₂O₃陶瓷;与常压烧结相比,高压烧结可显著降低烧结温度,提高传质速率,大幅度缩短烧结时间,达到快速、低温烧结的效果;由于相对较低的烧结温度,掺杂微量MgO的Al₂O₃陶瓷在高压烧结中未出现液相,MgO对烧结致密化及Al₂O₃晶粒生长抑制几乎无影响。     

Development and comparison of field assisted sintering techniques to densify CeO2 ceramics

Cerium dioxide (CeO₂) was densified by conventional and field assisted sintering techniques in order to examine the effect of a range of sintering parameters on the resultant pellet microstructure, namely: temperature, hold time, atmosphere, electric field strength and polarity. CS at 1400 °C for 2 h in static air atmospheres provided the highest densities and grain sizes compared with an argon atmosphere, due to the retention of near stoichiometry maintaining sintering kinetics. SPS produced dense ceramics at similar sintering temperatures (1300 °C), but with greatly reduced sintering hold (5 min) and cycle times. However, microstructural inhomogeneity arose from the direct current polarity which led to oxygen ion diffusion toward the positive electrode. FS was performed with an alternating current electric field and produces samples of comparable density at sintering temperatures of ~1100 °C for a hold time of around 1 h with no inhomogeneity due to the alternating current employed.