期刊
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
卷 33, 期 1, 页码 165-179出版社
ELSEVIER SCI LTD
DOI: 10.1016/j.jeurceramsoc.2012.07.024
关键词
Electron microscopy; Powders-gas phase reaction; Carbides; Grain growth; Reaction mechanisms
The carbothermal reduction of zirconia has been studied by TEM. The starting reactants consist in carbon black and monoclinic zirconia. Two successive steps are involved in the formation of the oxycarbide. The first one leads to the formation of an oxygen rich oxycarbide compound surrounded by an amorphous covering layer that regulates the achievement of species between gas and oxycarbide. The growth is controlled by three solid-gas partial reactions corresponding either to the destabilisation of the two products or to the nucleation and growth of the oxycarbide. The oxycarbide nucleation site is strictly located within the amorphous carbon. During the second step of the process, one of the initial constituents is missing (zirconia) and the previous solid-gas equilibriums are broken. The maturation of the oxycarbide into nearly stoichiometric carbide begins. The surrounding amorphous covering layer crystallises in carbon rich secondary carbide which progressively equilibrates in composition within the. inner primary one. (C) 2012 Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据