CAJ | 학술논문

采用石墨还原法探索了CeO2-ZrO2二元体系在不同还原温度、还原时间条件下的物相组成及结构，借助X射线衍射、红外振动光谱等手段对还原样品进行了物相表征及结构分析。实验结果表明：通过石墨还原能在较低温度（Tred＝1050℃）、较短时间（t＝24 h）内合成纯相Ce2 Zr2 O7.97，较传统先还原（95％ Ar＋5％ H2，Tred ≥1400℃，t＞48 h）后氧化（O2或空气气氛）工艺更简单经济；Ce2 Zr2 O7.97相能在1050～1300℃、24～72 h还原条件下稳定存在并保留至室温而不发生相分解，其机制可能归因于石墨所形成的弱还原环境；Ce2 Zr2 O7.97相拥有与烧绿石Ce2 Zr2 O7相近的有序阳离子亚晶胞结构，但由于其氧空位（O3、O4、O11）被大部分氧离子所填充，导致该相结构对称性降低。本文提出的石墨还原法制备富氧相Ce2 Zr2 O7.97有望成为一种较传统制备工艺更简单经济的新方法，而Ce2 Zr2 O7.97相能在还原气氛中稳定存在，可为An2 Zr2 O7＋ x固化体的存放环境提供借鉴和参考。
채용석묵환원법탐색료CeO2-ZrO2이원체계재불동환원온도、환원시간조건하적물상조성급결구，차조X사선연사、홍외진동광보등수단대환원양품진행료물상표정급결구분석。실험결과표명：통과석묵환원능재교저온도（Tred＝1050℃）、교단시간（t＝24 h）내합성순상Ce2 Zr2 O7.97，교전통선환원（95％ Ar＋5％ H2，Tred ≥1400℃，t＞48 h）후양화（O2혹공기기분）공예경간단경제；Ce2 Zr2 O7.97상능재1050～1300℃、24～72 h환원조건하은정존재병보류지실온이불발생상분해，기궤제가능귀인우석묵소형성적약환원배경；Ce2 Zr2 O7.97상옹유여소록석Ce2 Zr2 O7상근적유서양리자아정포결구，단유우기양공위（O3、O4、O11）피대부분양리자소전충，도치해상결구대칭성강저。본문제출적석묵환원법제비부양상Ce2 Zr2 O7.97유망성위일충교전통제비공예경간단경제적신방법，이Ce2 Zr2 O7.97상능재환원기분중은정존재，가위An2 Zr2 O7＋ x고화체적존방배경제공차감화삼고。
The phase composition and phase structure of CeO2-ZrO2 binary system were studied via graphite reduction method under different reducing temperatures and time . The various reduced products were characterized by powder X-ray diffraction and infrared spectra .Experimental results show that Ce2 Zr2 O7.97 phase can be synthesized successfully at a relative low temperature (Tred=1 050 ℃) and short time (t=24 h) by graphite reduction method , w hich is more simplified and economic than traditional reduction-reoxidation method with Ar-H2 (5% V/V hydrogen in argon ) reduction atmosphere .Ce2 Zr2 O7.97 phases prepared in a temperature range of 1 050-1 300 ℃ for 24-72 h are stable and can be retained until room temperature without phase decomposition .The mechanism may be attributed to a weak reduction environment formed by graphite .Ce2 Zr2 O7.97 phase with an ordered cation sub-unit cell structure is similar with pyrochlore Ce2 Zr2 O7 ,but the structure symmetry of Ce2 Zr2 O7.97 phase is lower than that of pyrochlore Ce2 Zr2 O7 due to the oxygen vacancy (O3 ,O4 ,O11) filled partially . Graphite reduction method is expected to become a new , simple and economical preparation method comparing with the traditional preparation process for Ce2Zr2O7.97 .The Ce2Zr2O7.97 phase retained at room temperature in a weak reducing atmosphere can provide a reference for the storage environment of An2 Zr2 O7+ x waste forms .