Hydrolysis-induced aqueous gelcasting for near-net shape forming of ZTA ceramic composites
✍ Scribed by Ibram Ganesh; Susana M. Olhero; Paula M.C. Torres; Fernando J. Alves; José M.F. Ferreira
- Publisher
- Elsevier Science
- Year
- 2009
- Tongue
- English
- Weight
- 930 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0955-2219
No coin nor oath required. For personal study only.
✦ Synopsis
A new near-net shape forming process called "hydrolysis-induced aqueous gelcasting" (GCHAS) is reported in this paper for the consolidation of ZTA composites, ZTA-30 (70 wt.% Al 2 O 3 + 30 wt.% ZrO 2 ) and ZTA-60 (40 wt.% Al 2 O 3 + 60 wt.% ZrO 2 ). For comparison purposes, ceramics having the same chemical compositions were also consolidated by hydrolysis-assisted solidification (HAS). All the starting suspensions contained a solids loading of 50 vol.%. In the precursor powder mixtures, 1-5 wt.% of Al 2 O 3 was replaced by equivalent amounts of AlN to enhance or promote or co-promote the consolidation of suspensions by HAS or by GCHAS, respectively. The suspensions for GCHAS were prepared by dispersing the ZTA powder precursor mixtures in a premix solution of 20 wt.% MAM (methacrylamide), MBAM (methylenebisacrylamide) and NVP (n-vinylpyrrolidinone) in 3:1:3 ratio in de-ionized water. Ceramics consolidated via GCHAS exhibited superior mechanical properties after consolidation and after sintering for 1 h at 1600 • C in comparison to those consolidated by HAS.