The Dislocation Analysis and Mechanical Property Measurements of Mullite and ZrO_2-Mullite Ceramics

共沉法合成富鋁紅柱石－二氧化鋯陶瓷之差排分析與機械性質

李建興(Jiann-Shing Lee) ； 余樹楨(Shu-Cheng Yu)

《鑛冶：中國鑛冶工程學會會刊》 40卷3期 (1996/09) Pp. 121-128+138

https://doi.org/10.30069/MM.199609_40(3).0014

摘要

Mullite and ZrO_2-mullite were prepared using co-precipitation method with ZrO(NO_3)_2, AI(NO_3)_3 and silica sol as precursor materials. With two-beam conditions in electron microscopy study, dislocations of ZrO_2-mullite (15wt% ZrO_2)with Burgers vectors in [001] and [213] directions are observed. The former dislocation is much more abundant in defect density than the later one. The prevailing dislocations with Burgers vector parallel to the c-axis in mullite is consistent with the fact that [001] is a prominent direction for chains of AlO_6 octahedra and double chains of (AI, Si)O_4 tetrahedra in mullite structure. Mechanical property measurements on mullite with various ZrO_2 concentrations were also made. Both flexural strength and fracture toughness are significantly improved for ZrO_2-mullite. With ZrO_2 content in mullite increased from 0 to 30%, flexural strength was found to increase from 346 to 551 MPa and fracture toughness from 1.88 to 3.92 MPa-m^(-1.5). Measurements on mechanical properties for flexural strength and fracture toughness were found to be independent on the Al_2O_3 concentration in mullite.

關鍵字

Mullite ； Zirconia ； Dislocation analysis ； Mechanical property

並列摘要

本研究以硝酸氧鋯、硝酸鋁及二氧化矽溶膠為起始原料，並利用化學共沉法來製備富鋁紅柱石及其與二氧化鋯複合之陶瓷。其中，以穿透式電子顯微鏡分析含有15％ZrO_2之富鋁紅柱石燒結體中的差排現象，發現有Burgers向量平行於［001］及［213］方向之差排，其中以平行於［001］方向之差排的發育較為明顯，此現象可以富鋁紅柱石中之晶體結構來解釋。將富鋁紅柱石與二氧化鋯之複合燒結體做機械性質之分析，發現彎曲及破壞韌性皆因ZrO_2之添加而有明顯的提升。隨著ZrO_2之含量從0％漸增至30％，複合燒結體之彎曲強度則由346MPa增加為551MPa，而其破壞韌性則從1.88 MPa-m^(-1.5)提高為3.92MPa-m^(-1.5)。至於富鋁紅柱石之破壞韌性及彎曲強度，在本研究之成份範圍內，並未發現與Al_2O_3之含量變化有明顯的關係。

並列關鍵字

富鋁紅柱石 ； 二氧化鋁 ； 差排分析 ； 機械性質