K9光学玻璃化学钢化技术研究

为提高K9光学玻璃在一些特殊应用领域（如高压、温度变化剧烈等）的力学性能，并保证其光学性能符合精密光学仪器要求，对K9光学玻璃进行了化学钢化技术研究。以脆性材料断裂过程微裂纹扩展理论为基础，导出化学钢化玻璃强度应力因子计算模型，分析化学钢化表面应力与表面微裂纹深度、韧性之间的关系，指出化学钢化工艺应注意的事项。通过实验研究，分析化学钢化温度和钢化时间对K9光学玻璃抗弯强度、表面应力及应力层厚度的影响，优化得出K9光学玻璃化学钢化温度为400 ℃、钢化时间为40 h。采用优化工艺，获得了表面应力为500 MPa、应力层厚度为50 μm量级及规格为220 mm×110 mm×22 mm的化学钢化K9光学玻璃样件。钢化后，样件抗弯强度提高了3.5倍以上，且表面疵病、光学鉴别率、透过率等光学性能指标未见明显变化。

Research on chemical strengthening technology for K9 optical glass

In order to improve the mechanical properties of K9 optical glass,which used in some special fields such as heavy pressure and drastic temperature changing,etc,and ensure the optical properties can meet the requirements of precision optical instruments,the chemical strengthening technology for K9 optical glasses was studied.Based on the theory of crack propagation during the fracture process of brittle materials,the calculation model of stress intensity factor for chemical strengthened K9 optical glasses was formulated.The relations between glass surface stress,surface micro-crack depth and toughness were discussed,and several problems in the chemical strengthening process needed to attention were pointed out.By experimental research,the effects of strengthening temperature and time on the strength,surface stress and stress depth of K9 optical glasses were analyzed.The chemical strengthening process for K9 optical glass was optimized,the strengthening temperature is 400℃and the strengthening time is 40 h.The measured results of mechanics and optical properties for K9 optical glasses with size of 220 mm×110 mm×22 mm are obtained.The measured results show that the surface stress is 500 MPa,the stress depth is about 50μm,the bending strength is increasing more than 3.5 times,and the optical discrimination and transmittance show no obvious changing.