High temperature calorimetry has been used to determine enthalpies of mixing and of vitrification and fusion in silicate, aluminosilicate, and borosilicate systems. The systems Na//2O-Al//2O//3-SiO//2 and Na//2O-B//2O//3-SiO//2 show contrasting behavior. In the former, the join SiO//2-NaAlO//2 shows large energetic stabilization near Al/(Al plus Si) equals 0. 5, whereas in the latter, much less pronounced stabilization is seen along the join SiO//2-NaBO//2. More B//2O//3-rich compositions, e. g. , the join SiO//2-Na//0//. //3//1B//1//. //2//3O//2 (B/Na equals 4) show substantial positive heats of mixing, presumably related to immiscibility. Thermodynamic data for the complete Na//2O-B//2O//3-SiO//2 ternary system are being developed. Borosilicate glasses are a leading candidate for immobilization of high-level nuclear waste; thus their thermodynamic characterization is important to predicting the long-term stability of such depositories.
|Original language||English (US)|
|Number of pages||18|
|Journal||High temperature science|
|State||Published - Apr 1 1984|
|Event||Proc of the 4th Int Conf on High Temp and Energy-Relat Mater, Pt 2 - Santa Fe, NM, USA|
Duration: Apr 1 1984 → Apr 6 1984
ASJC Scopus subject areas