1. Scientific Foundations Of Hollow Glass Microspheres 1.one Composition and Microstructure one.1.1 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 typically features silica (SiO₂, 50-90%), alumina (Al₂O₃, ... https://www.jointcorners.com/post/483699_elementary-substance-is-a-pure-chemical-substance-that-consists-of-atoms-belongi.html