无机材料学报

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非晶晶化法制备 Si-Al-Zr-O系超微细晶复相陶瓷

谭小平, 梁叔全, 李少强, 唐艳   

  1. 中南大学材料科学与工程学院, 长沙 410083
  • 收稿日期:2005-08-09 修回日期:2005-10-11 出版日期:2006-07-20 网络出版日期:2006-07-20

Preparation of Si-Al-Zr-O Composite Ceramics with Ultra Fine Grains by in situ Controlled Crystallizing from the Amorphous Bulk

TAN Xiao-Ping, LIANG Shu-Quan, LI Shao-Qiang, TANG Yan   

  1. School of Materials Science and Engineering, Central South University, Changsha 410083, China
  • Received:2005-08-09 Revised:2005-10-11 Published:2006-07-20 Online:2006-07-20

摘要: 在1650~1700℃下制备了Si-Al-Zr-O(SAZ)溶胶, 经快速冷却获得均匀致密的SAZ系非晶体, 经梯度热处理得到SAZ系超微细晶复相陶瓷. 结合示差扫描量热分析(DSC)、红外光谱(IR)、X射线衍射(XRD)和扫描电镜(SEM)等技术以及Vicker压痕法, 研究了相关超微细晶复相陶瓷结构和性能随热处理温度的变化. 结果表明, SAZ系非晶体在950℃时开始析出四方氧化锆, 1100℃时晶化基本完成, 主晶相为莫来石和四方氧化锆, 晶粒尺寸为10~40nm; 温度升高至1200℃, 晶粒迅速长大至0.5μm左右, 部分四方氧化锆向单斜氧化锆的转变. 样品的显微硬度和断裂韧性经1150℃热处理后均达到最大, 分别为12.6GPa和4.32MPa·m1/2

关键词: Si-Al-Zr-O系, 非晶, 热处理, 结构, 性能

Abstract: The homogeneous SiO2-Al2O3-ZrO2(SAZ) sol was prepared at 1650~1700℃ and transparent amorphous bulk was obtained by controlling the cooling process. The bulk was treated at 950℃ for 2h to nucleate and at 1100~1250℃ for 1h to crystallize, and SAZ composite ceramics with ultra fine grains were prepared. The effects of heat treatment on the structure and properties of the composite caramics were analyzed by using DSC, IR, XRD, SEM and Vickers indentation techniques. The results show that crystallization of SAZ amorphous
bulk begins with t-ZrO2 at about 950℃ and completes at about 1100℃. The
main phases are mullite, t-ZrO2. With the increase of crystallization temperatures, the gains grow rapidly from 10~40nm to 0.5μm, and the transformation of zirconia from tetragonal into monoclinic occurs. The values of microhardness and fracture toughness are largest at 1150℃, those are 12.6GPa and 4.32MPa·m1/2 respectively.

Key words: Si-Al-Zr-O system, amorphous bulk, heat treatment, structure, properties

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