光学工程应力分布玻璃的工艺研究
发布时间：2018-08-18 18:04
【摘要】：硅酸盐玻璃在国民经济各个领域中发挥着重要作用。其脆性特征使得其实际断裂强度远低于理论强度,通过传统的钢化技术,其实际断裂强度得到很大的改善,但一些特殊领域对其断裂的集中性有很高的要求。工程应力分布(Engineered Stress Profile,ESP)玻璃的出现为这类问题的解决提供了很好的研究方向,其中最为突出的工艺制备方法是低温两步离子交换法。本文采用低温两步离子交换法对厚度为1.1mm的超薄钠铝硅系玻璃进行增强,制备ESP玻璃。通过改变其工艺参数,运用电子探针微观结构测试方法,结合表面应力、弯曲强度、显微硬度和透过率等测试,研究单步离子交换法工艺参数对玻璃性质的影响,两步离子交换法与单步离子交换法制备玻璃性质的不同以及第一步离子交换工艺参数对ESP玻璃性质的影响。研究结果表明:1)对钠铝硅玻璃进行单步离子交换,时间和温度显著影响玻璃弯曲强度及Weibull模数。超过12h后,时间的延长使得弯曲强度逐渐降低,Weibull模数先升高后降低;随着温度的增大,弯曲强度与Weibull模数先升高后降低。450℃下进行40h获得最大的Weibull模数35.82,弯曲强度为397.72 MPa。通过菲克第二定律计算得出450℃时,K+扩散系数为1.102×10-14m2/s,使用Boltzmann-Matano方法计算出450℃时,K+扩散系数为2.92×10-14m2/s。2)对玻璃进行两步离子交换时,第二步交换时间显著影响玻璃的Weibull模数。第二步交换介质为质量比为3:7的NaNO3和KNO3混合熔融盐。随着第二步交换时间的延长,弯曲强度与Weibull模数先增大后降低,并在第二步离子交换时间为30 min均达到最大值,弯曲强度达到421.67 MPa,Weibull模数达到48.97。并证明了ESP玻璃提高Weibull模数的机理:K+富集峰位置随着第二步时间的延长的向玻璃内部移动,Na+向玻璃近表面区域扩散,近表面区域应力梯度提升,最大应力值向内部移动,裂纹稳定扩展区域内裂纹停止扩展或稳定扩展,从而导致玻璃断裂集中度提升。3)对ESP玻璃在受力与未受力情况下的抗裂纹能力进行研究。两步法钢化玻璃的裂纹深度与裂纹半长a/c比单步法玻璃还要低较低,说明ESP玻璃形成的高梯度的应力分布使得玻璃在抗裂纹向玻璃深度方向扩展上有很大提高。使用显微硬度仪对玻璃预制裂纹,进行弯曲强度测试,结果显示,ESP玻璃在受外力条件下显现出了极高裂纹抗性。微裂强度计算结果表明ESP玻璃相比单步法玻璃在不受外力情况下具有更高的抗裂纹能力。4)对玻璃进行两步离子交换时,第一步交换温时间和温度决定了ESP玻璃的弯曲强度,并决定了获取高Weibull模数玻璃时的第二步交换时间。使用K+富集峰向玻璃内部移动速度的比较,得出结论:合适的温度和较长时间的第一步离子交换与较短时间的第二步离子交换才能获得高Weibull模数ESP玻璃。5)本文通过实验获得了七组制备Weibull模数大于40玻璃的工艺参数,适用于力学敏感玻璃的制备。通过透过率测试,所制备的ESP玻璃透过率均在84%左右,具有光学应用性能,可以称为光学工程应力分布玻璃。
[Abstract]:Silicate glass plays an important role in various fields of national economy. Its brittleness makes its actual fracture strength much lower than the theoretical strength. Through traditional tempering technology, its actual fracture strength has been greatly improved, but some special fields require high concentration of its fracture. The emergence of ESS Profile (ESP) glass provides a good research direction for solving these problems. The most prominent method is the two-step ion exchange method at low temperature. The influence of process parameters on the properties of ESP glass by single-step ion-exchange method, the difference of glass properties between two-step ion-exchange method and single-step ion-exchange method, and the influence of process parameters on the properties of ESP glass by the first-step ion-exchange method were studied by means of electron probe microscopic structure test and surface stress, bending strength, microhardness and transmittance measurements. The results show that: 1) The bending strength and Weibull modulus of sodium alumina silicate glass are significantly affected by the time and temperature of single-step ion exchange. The maximum Weibull modulus was 35.82 and the bending strength was 397.72 MPa. The K + diffusion coefficient was 1.102 65 The second step is NaNO 3 and KNO3 mixed molten salts with mass ratio of 3:7. With the extension of the second step, the bending strength and Weibull modulus increase first and then decrease, and reach the maximum value in the second step when the ion exchange time is 30 minutes. The bending strength reaches 421.67 MPa and the Weibull modulus reaches 48.9 MPa. 7. The mechanism of increasing Weibull's modulus in ESP glass is proved: the position of K + enrichment peak moves to the glass interior with the extension of the second step time, Na + diffuses to the near-surface region of the glass, the stress gradient in the near-surface region rises, the maximum stress value moves to the interior, and the crack in the stable crack growth region stops or propagates steadily, which leads to the glass. The crack depth and crack half-length a/c of the two-step tempered glass are lower than that of the single-step tempered glass, which indicates that the high gradient stress distribution formed by the ESP glass makes the glass have a large crack resistance to the depth of the glass. The results show that ESP glass exhibits very high crack resistance under external force. The results of micro-crack strength calculation show that ESP glass has higher crack resistance than single-step glass without external force. The bending strength of ESP glass is determined by the first step exchange temperature time and temperature, and the second step exchange time for obtaining high Weibull modulus glass is determined. In order to obtain high Weibull modulus ESP glass.5) In this paper, seven groups of technological parameters for preparing glass with Weibull modulus greater than 40 were obtained through experiments, which are suitable for the preparation of mechanical sensitive glass.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ171.1
[Abstract]:Silicate glass plays an important role in various fields of national economy. Its brittleness makes its actual fracture strength much lower than the theoretical strength. Through traditional tempering technology, its actual fracture strength has been greatly improved, but some special fields require high concentration of its fracture. The emergence of ESS Profile (ESP) glass provides a good research direction for solving these problems. The most prominent method is the two-step ion exchange method at low temperature. The influence of process parameters on the properties of ESP glass by single-step ion-exchange method, the difference of glass properties between two-step ion-exchange method and single-step ion-exchange method, and the influence of process parameters on the properties of ESP glass by the first-step ion-exchange method were studied by means of electron probe microscopic structure test and surface stress, bending strength, microhardness and transmittance measurements. The results show that: 1) The bending strength and Weibull modulus of sodium alumina silicate glass are significantly affected by the time and temperature of single-step ion exchange. The maximum Weibull modulus was 35.82 and the bending strength was 397.72 MPa. The K + diffusion coefficient was 1.102 65 The second step is NaNO 3 and KNO3 mixed molten salts with mass ratio of 3:7. With the extension of the second step, the bending strength and Weibull modulus increase first and then decrease, and reach the maximum value in the second step when the ion exchange time is 30 minutes. The bending strength reaches 421.67 MPa and the Weibull modulus reaches 48.9 MPa. 7. The mechanism of increasing Weibull's modulus in ESP glass is proved: the position of K + enrichment peak moves to the glass interior with the extension of the second step time, Na + diffuses to the near-surface region of the glass, the stress gradient in the near-surface region rises, the maximum stress value moves to the interior, and the crack in the stable crack growth region stops or propagates steadily, which leads to the glass. The crack depth and crack half-length a/c of the two-step tempered glass are lower than that of the single-step tempered glass, which indicates that the high gradient stress distribution formed by the ESP glass makes the glass have a large crack resistance to the depth of the glass. The results show that ESP glass exhibits very high crack resistance under external force. The results of micro-crack strength calculation show that ESP glass has higher crack resistance than single-step glass without external force. The bending strength of ESP glass is determined by the first step exchange temperature time and temperature, and the second step exchange time for obtaining high Weibull modulus glass is determined. In order to obtain high Weibull modulus ESP glass.5) In this paper, seven groups of technological parameters for preparing glass with Weibull modulus greater than 40 were obtained through experiments, which are suitable for the preparation of mechanical sensitive glass.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ171.1
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