One. Scientific Foundations of Hollow Glass Microspheres one.1 Composition and Microstructure one.1.1 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 incorporates silica (SiO₂, 50-90%), alumina ... https://expressafrica.net/post/401199_trunnano-focuses-on-providing-a-full-range-of-high-quality-3d-printing-powders-t.html