硫化镍引发钢化玻璃自爆的临界尺寸及影响

基于变形协调关系及均强度理论, 定量计算了硫化镍相变体积膨胀对玻璃的挤压应力、因硫化镍和玻璃热膨胀系数不匹配导致的内应力及以上两者协同作用下导致的硫化镍颗粒周边的局部集中应力的影响, 分析了硫化镍直径、玻璃局部强度及环境温度对钢化玻璃自爆的影响, 确定了引发钢化玻璃自爆的硫化镍颗粒的临界直径。研究结果表明: 硫化镍颗粒周边的周向集中应力(拉应力)是导致钢化玻璃自爆的根本原因。随着硫化镍直径的增大, 其周向应力也增大, 但不呈线性关系, 当颗粒直径小于0.2 mm时, 其周向应力迅速降低, 而当颗粒直径大于0.5 mm时, 其周向应力增大幅度变缓。随着钢化玻璃表面应力的增大, 引发自爆风险的硫化镍临界直径逐渐减小, 直径小于0.1 mm的硫化镍很难引发钢化玻璃自爆。周向应力与环境温度升高呈线性增长趋势, 且大颗粒尺寸的硫化镍周向应力增长速率更快。

Critical Size on Spontaneous Breakage of Tempered Glass Initiated by NiS Particle

Extrusion stress due to phase change of the NiS,internal stress due to CTE mismatch between the NiS and glass,and local concentrated stress around the NiS due to synergistic effects above were quantitatively calculated based on equal strength theory and the deformation coordination relation between NiS and glass in this work.The effects of NiS particle diameter,local strength of glass and ambient temperature on spontaneous breakage of tempered glass were analyzed.The critical diameter of NiS particles was determined as well.The results show that the fundamental reason for spontaneous breakage of tempered glass is the circumferential concentrated stress(tensile stress)near the NiS particle.There exists non-linear relations between circumferential stress and NiS particle diameter of which the circumferential stress decreases rapidly with the decrease of NiS particle diameter when it is less than 0.2 mm,but circumferential stress increases moderately when it is greater than 0.5 mm.The critical diameter of NiS particle which causes the spontaneous breakage of tempered glass decreases with the increase of surface stress in the tempered glass.It is difficult to induce spontaneous breakage of tempered glass when the diameter of NiS particle is less than 0.1 mm.The circumferential stress increases linearly with the increase of ambient temperature,and the stress increases slightly faster for the NiS with larger diameter.