Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
831657 | Materials & Design (1980-2015) | 2011 | 8 Pages |
Alumina ceramic composites toughened with various contents of fine-sized zirconia particulates were fabricated via cyclic infiltrating pre-sintered alumina preforms with zirconium oxychloride solution and immersion in ammonia solution to induce in situ precipitation. Homogeneous distribution of zirconia throughout the bulk material has been substantiated by line-scan analysis and backscattering images taken from sections with different distances from surface. It was found that a higher drying temperature and increase in infiltration numbers lead to a greater zirconia content and bigger grain size. The hardness of fabricated zirconia toughened alumina composite was firstly improved probably due to the microstructure refining effect, while a further increase in zirconia content results in the decrease of hardness. A significantly higher indentation toughness has been observed for samples containing >10 wt.% zirconia compared with other specimens, which could be attributed to the coarser zirconia grain size and the related greater tendency to transformation into monoclinic phase.
Research highlights► Homogeneous ZTA with fine microstructure can be fabricated via cyclic infiltration. ► Drying temperature and infiltration numbers decide zirconia content and grain size. ► Transformation tendency of ZrO2 is probably responsible for the improved toughness.