One. Scientific Foundations of Hollow Glass Microspheres one.one 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 very low thermal expansion coefficient and chemical inertness. The chemical makeup usually features silica (SiO₂, 50-ninety%), alumina ... https://www.geto.space/post/74062_elementary-substance-is-a-pure-chemical-substance-that-consists-of-atoms-belongi.html