1. Scientific Foundations of Hollow Glass Microspheres one.1 Composition and Microstructure 1.one.1 Chemical Composition: Borosilicate Dominance Hollow glass microspheres (HGMs) are mainly made up of borosilicate glass, a material renowned for its small thermal expansion coefficient and chemical inertness. The chemical make-up normally involves silica (SiO₂, 50-90%), alumina (Al₂O₃, t... https://hackmd.io/@okok0972/r16JHVs6xg