1. Scientific Foundations of Hollow Glass Microspheres 1.one Composition and Microstructure 1.1.1 Chemical Composition: Borosilicate Dominance Hollow glass microspheres (HGMs) are principally made up of borosilicate glass, a fabric renowned for its reduced thermal expansion coefficient and chemical inertness. The chemical make-up ordinarily incorporates silica (SiO₂, 50-90%), alumina ... https://500px.com/photo/1117584688/boride-powder-by-okok-okok