Stress-induced β→α-cristobalite phase transformation in (Na2O+Al2O3)-codoped silica

摘要: Abstract Colloidal gel-derived silica (SiO2) powder codoped with (Na2O+Al2O3) was sintered at 1100 °C. The crystalline phase content and transformation of the ceramics have been studied via X-ray diffractometry scanning electron microscopy. amount β-cristobalite retained metastably in mixture to room temperature is found depend on level additives. Samples Na2O Al2O3, both 6.30 mol%, were contain only mixture, which known as chemically stabilized cristobalite (CSC). Multiple liquid separation also observed samples. lattice spacing d101α α-cristobalite increases doping while d111β β-phase remains almost unchanged all compositions studied. Surface grinding or pulverizing samples into induces β→α-cristobalite transformation. mechanism high stabilization associated chemical mechanical terms discussed.