Mechanical and thermal properties of calcium-magnesium aluminosilicate (CMAS) glass

摘要

Thermal stability of a synthetic sand composition, which was developed as a simulant for calcium magnesium aluminosilicate (CMAS) turbine deposits, was characterized using thermogravimetric and differential thermal analysis (TG/DTA). The sand was melted into CMAS glass, which had a composition of 23.3CaO-6.4MgO-3.1Al(2)O(3)-62.5SiO(2)-4.1Na(2)O-0.5K(2)O-0.04Fe(2)O(3) (mol.%), determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Bulk density of the glass was measured to be 2.63 g/cm(3), and the Young's and shear moduli were 84.3 GPa and 33.6 GPa, respectively, along with a Poisson's ratio of 0.26. Vickers microhardness and indentation fracture toughness were determined to be 6.14 +/- 0.1 GPa and 0.70 +/- 0.05 MPa m(1/2), respectively. Glass transition temperature, softening point and coefficient of thermal expansion of the glass were measured by dilatometry. Glass viscosities were estimated over a temperature range of 600-1500 degrees C using dilatometric reference points of the glass and from composition-based methods. Times required for infiltration of molten CMAS glass into thermal or environmental bather coatings were also estimated. Published by Elsevier Ltd.