Evaluation of glass properties using Gibbs energy of oxide melts optimized by CAPHPHAD method

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04996
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26020:Inorganic materials and properties-related
• Research Institution: Akita University
• Principal Investigator: Sugawara Toru 秋田大学, 理工学研究科, 准教授 (40420492)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: ケイ酸塩メルト / ガラス / マグマ / ガラス固化体

Outline of Final Research Achievements

We investigated the general applicability of the thermodynamic database of silicate melts optimized by CALPHAD method. The equilibrium constant between glass and water calculated using the database was in agreement with the experimental value by the leachability test, suggesting that the database can be applied to predict the chemical durability of glass. However, the glass forming ability does not match the actual one in the system containing Al2O3, so it is necessary to reexamine the thermodynamic quantity of alumino-silicate melts.
In addition, the heat capacity of the SiO2-B2O3-Na2O system was determined as basic data for future expansion of the database. The temperature and compositional dependence of the partial molar heat capacity of B2O3 was discussed based on the new experimental data.

Free Research Field

マグマ学，ガラス工学

Academic Significance and Societal Importance of the Research Achievements

火山のマグマ，鉄鋼製錬のスラグやガラス融体はいずれもSiO2を主成分とする酸化物融体であり，その熱力学的性質は地球科学から材料工学に渡り幅広く応用できる可能性を持っている．近年，相平衡データに基づくCALPHAD法の解析が進展し，多成分系ケイ酸塩メルトの熱力学量が定式化されるようになった．本研究は熱力学データベースの汎用的な応用の可能性を検討し，現段階ではガラスの化学的耐久性とAl2O3を含まないメルトのガラス形成能の評価に適用することができることを見出した．熱力学データベースは高温プロセス産業のさまざまな工程に関わる予測精度を向上させることができる可能性があることが示された．