One. Scientific Foundations of Hollow Glass Microspheres 1.one Composition and Microstructure 1.one.one Chemical Composition: Borosilicate Dominance Hollow glass microspheres (HGMs) are mostly made up of borosilicate glass, a material renowned for its small thermal expansion coefficient and chemical inertness. The chemical make-up normally consists of silica (SiO₂, 50-ninety%), alumin... https://500px.com/photo/1117584688/boride-powder-by-okok-okok