One. Scientific Foundations of Hollow Glass Microspheres one.1 Composition and Microstructure one.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 typically features silica (SiO₂, 50-90%), alumina (A... https://www.speakfreelee.com/post/78605_elementary-substance-is-a-pure-chemical-substance-that-consists-of-atoms-belongi.html