... size(3-40um) high crush strength (60000psi) low cost SN-Spheres are a series of separated products directly from fly ... low reactivityCrush Strength50000-90000psiFlammabilityNot combustibleMelting point1450oC approx.SolubilityNegligible in waterGrade SN-sphereSN-40SN-20SN-10SN-5SN-3Particle Size Range (micron)=<40 ... soldiers, heat and compression insulating compounds, deep-water submarine. SN-sphere