离子交换温度对化学钢化玻璃结构和性能的影响

离子交换法制备钠铝硅系化学钢化玻璃,分析测试玻璃表面K+和Na+的分布情况、玻璃的表面应力及应力层深度、弯曲强度、Weibull模量和显微硬度,研究离子交换温度对化学钢化玻璃在结构和性能上的影响.结果表明:经过离子交换后,玻璃的表面应力、弯曲强度、Weibull模量和显微硬度均显著提高.提高离子交换温度,玻璃表面应力、弯曲强度和显微硬度逐渐下降,应力层深度逐渐加厚.温度350℃时,玻璃表面离子交换层具有全K+层、K+-Na+层和富K+层三层结构.温度升高,全K+层消失和富K+层,K+-Na+层加厚并出现贫Na+层.温度410℃时玻璃的强度分散性最小,可靠性最高.     

超薄铝硅玻璃离子交换工艺研究

高强度超薄盖板玻璃是电子信息产品的重要组成部分,化学强化(离子交换)是提升超薄盖板玻璃力学性能的主要技术途径。在离子交换过程中,玻璃易产生应力弛豫等现象,导致化学强化玻璃难以具备较高的表面压应力、较大的应力层深度与较高的维氏硬度。本文采用两步法离子交换工艺,研究了熔盐、离子交换温度与时间等因素对强化后超薄铝硅玻璃应力层分布及维氏硬度等性能的影响。结果表明,本文所研发的两步法离子交换工艺,可以使玻璃兼具较高的表面压应力、较大的应力层深度与较高的表面维氏硬度。离子交换后,铝硅玻璃的表面压应力可达900 MPa以上,应力层深度可达70 μm以上,同时表面维氏硬度达7.2 GPa以上。     

浮法超薄玻璃化学钢化及性能研究

本文研究高铝超薄浮法玻璃与浮法钠钙硅玻璃的化学钢化过程.用全自动化学钢化玻璃表面应力测试仪、万能试验机和数显显微维氏硬度计分别测试了样品的表面应力、应力层深度、抗折强度和显微硬度.结果表明:在一定的温度下,随着离子交换时间的增加,高铝超薄玻璃与浮法钠钙硅玻璃的表面应力、抗折强度、显微硬度均出现先增加再到减小的趋势,应力层深度则随着时间的增加而加深.在同样的离子交换制度下,高铝玻璃化学钢化后的力学性能优于钠钙硅玻璃.同时,以浮法工艺生产的玻璃锡面的表面应力小于非锡面的应力,应力层深度也相对小于非锡面的深度.     

P2O5含量对铝硅酸盐玻璃离子交换性能的影响

通过对玻璃进行了离子交换实验,研究P2O5含量变化对铝硅酸盐玻璃离子交换性能的影响.利用显微硬度仪、表面应力仪、微区X射线荧光光谱仪和场发射扫描电子显微镜线扫分别表征了离子交换玻璃的硬度、表面应力、元素含量变化和离子交换深度等性能.结果表明:离子交换后玻璃表面的K+含量明显增加,Na+含量降低,玻璃表面发生了明显的离子交换.此外,随着P2O5含量的增加,离子交换后的玻璃的硬度、表面应力和离子交换层深度逐渐增加.实验结果证明P2O5的引入能有效促进铝硅酸盐玻璃离子交换.     

Na+浓度对化学增强钠铝硅酸盐玻璃性能的影响

熔盐中少量的Na⁺并不会对玻璃的离子交换效果产生明显影响,但当熔盐中Na⁺浓度不断增大时,化学增强钠铝硅酸盐玻璃的性能开始受到影响。本文采用一步法离子交换工艺研究了熔盐中Na⁺浓度对不同厚度化学增强钠铝硅酸盐玻璃表面压应力、应力层深度和弯曲强度等性能的影响。研究表明:熔盐中Na⁺浓度不断增大时,化学增强钠铝硅酸盐玻璃的表面压应力、弯曲强度下降;弯曲强度下降最多可达175 MPa,此时玻璃的表面压应力下降了57.4 MPa;熔盐中Na⁺浓度变化未对化学增强钠铝硅酸盐玻璃的应力层深度和可见光透过率产生明显影响。     

高铝硅玻璃二次化学钢化增强工艺研究

研究超薄高铝硅酸盐玻璃经过两次钾钠混合熔盐的离子交换强化处理后表面压应力、显微维氏硬度、抗冲击强度以及离子交换深度的变化情况。实验结果表明,通过二次交换强化处理后,玻璃的表面压应力由83.4 MPa提升到925.3 MPa,显微维氏硬度由657.5提升到875.1,落球测试高度由18.3 cm提升到45.7 cm, K⁺的扩散深度也由一步离子交换的27μm提升到二步离子交换的44μm。     

熔盐添加剂对玻璃离子交换和增强的影响

在工业纯KNO3中分别添加KOH,K3PO4,K2CO3,K2SiO3与Al2O3的混合物,研究了熔盐添加剂对浮法玻璃离子交换和增强的影响.用电子探针测试了玻璃表而的K+浓度;测定了样品的表面应力、弯曲强度和显微硬度.结果表明:上述添加剂町以增加离了交换层深度,缩短离子交换时间,明显提高玻璃的力学性能,其增强效果与分析纯KNO3的增强效果相当,甚至比后者好:在交换温度为450℃下,玻璃交换层厚度大于29μm,玻璃的力学性能为:表面应力>480MPa,弯曲强度>400MPa.显微硬度为6.49GPa.     

离子交换增强玻璃

离子交换玻璃的压缩层深度范围为0.25～0.5毫米,它比物理钢化的深度小。离子交换玻璃的表面比物理钢化表面更耐磨损。 由于薄玻璃不能用物理钢化来产生高的压缩应力,最好选择离子交换的方法。离子交换后的玻璃能够得到象平板玻璃物理钢化那样的强度,但其厚度仅为平板玻璃的1/4～1/5。     

普通薄玻璃化学钢化

以普通钠钙硅浮法玻璃为原片,用低温型离子交换法进行试验,通过对试验样品的表面应力、应力层深度、显微硬度及抗折强度等数据的测试,研究普通浮法玻璃离子交换的工艺制度。     

热处理与二次化学强化对玻璃应力层深度的影响

应力层深度是衡量化学强化玻璃抵抗裂纹扩展能力的重要指标,提高应力层深度对于改善化学强化玻璃的使用性能具有重要的意义.以国产高铝玻璃为研究对象,研究了化学强化与热处理对玻璃应力层深度、表面压应力和抗弯强度的影响.研究表明,对化学强化玻璃的热处理可以显著增加玻璃的应力层深度,但是抗弯强度也会明显降低;对热处理后的玻璃的二次化学强化,可进一步增加玻璃的应力层深度,并显著提升玻璃表面压应力与抗弯强度.该方法在不延长工艺时间的前提下,可显著增加玻璃的应力层深度,并避免高温或长时间化学强化所引起的力学性能降低.     

散射光弹性技术在化学钢化玻璃表面应力测量中的应用

在智能手机、平板电脑等电子产品领域,化学钢化超薄玻璃的需求不断增加,而玻璃是易碎材料,要提高或保持强度和抗破碎能力,必须正确认识应力分布。如何有效的测量化学钢化玻璃的表面压应力(CS)和压应力层厚度(DOL),是当下一个迫切需要解决的问题。散射光弹性法是利用通过玻璃内部应力的双折射来改变极化激光束的延迟,并且散射光的强度随着激光束的延迟的变化而改变,最后通过偏振光光路上因激光束的延迟而出现的光程差和偏振特性来计算表面压应力和压应力层厚度。对散射光弹性法测量化学钢化玻璃的表面应力的理论依据、测量技术等进行了介绍。     

锂铝硅玻璃的研究进展

与传统的钠钙硅玻璃和高铝玻璃相比,锂铝硅玻璃具有网络结构致密、弹性模量较高和适宜两步法化学钢化等特点,被视为第三代高强玻璃基板,可用作电子信息产品盖板、航空透明器件以及舰船、特种车辆的观察窗口等。目前,锂铝硅玻璃的研究主要涉及:(1)探究锂铝硅玻璃的“组成-结构-性能”本构关系,为设计优化高性能锂铝硅玻璃提供理论指导和性能预测;(2)改进现有溢流和浮法成型方法和装备,满足大尺寸、多厚度和高尺寸精度锂铝硅玻璃成型需要;(3)研究锂铝硅玻璃的两步法化学增强方法,解决表面压应力和应力层深度同步提升难题,显著提高玻璃强度、硬度和抗跌落性能。本文基于上述三个方面综述了锂铝硅玻璃的国内外研究进展。     

光波导效应在化学钢化玻璃表面应力测量中的应用

随着国际市场对化学钢化玻璃的需求不断增加,目前化学钢化的超薄玻璃在电子、仪表、和智能化科技行业的应用领域广泛使用。化学钢化玻璃的表面压应力(CS)和压应力层厚度(DOL),是业界认可的最重要的性能指标,而如何准确的表征这些参数,是当下一个迫切需要解决的问题。化学钢化玻璃表面层中的光导效应是用于测量表面应力的有效途径,可以有效的测量化学钢化玻璃的CS和DOL,从而用于钢化玻璃生产中的质量和过程控制。本文对基于光波导效应的表面应力计的理论依据、测量技术和相关仪器进行了介绍。     

Influence of Surface Structure on the Fracture Toughness of Tempered Glass

A nondestructive measurement of the surface stress and an indentation technique were used to determine the relationship between the fracture toughness and the surface compressive stress of a tempered glass plate. Ignoring the effect of surface compression, one can determine the fracture toughness concerned only with a change in the glass structure. It is found that the fracture toughness is lower for tempered glass than for annealed glass. It is indicated that the decrease is due to structural changes in the surface layer during the heat treatment in tempering; this is confirmed by infrared reflection spectroscopy.     

Compressive strength and wear properties of SiC/Al6061 composites reinforced with high contents of SiC fabricated by pressure-assisted infiltration

Pressure-assisted infiltration was used to synthesize SiC/Al 6061 composites containing high weight percentages of SiC. A combination of PEG and glass water was used to fabricate SiC preforms and the effect of the presence of glass water on the microstructure and mechanical properties of the preforms was evaluated by performing compression tests on the preforms. Also, the compressive strength and the hardness of the SiC/Al composites were investigated. The results revealed that the glass water improved the compressive strength of the preforms by about five times. The microstructural characterization of the composites showed that the penetration of the aluminum melt into the preforms was completed and almost no porosity could be seen in the microstructures of the composites. Moreover, the composite containing 75 wt% SiC exhibited the highest compressive strength as well as the maximum hardness. The results of the wear tests showed that increasing the SiC content reduces the wear rate so that the Al-75 wt% SiC composite has a lower wear rate and a lower coefficient of friction than those of Al-67 wt% SiC composite. This indicated higher wear resistance in these composites than the Al alloy due to the formation of a tribological layer on the surface of the composites.     

Ion-Exchanged Glass Laminates that Exhibit a Threshold Strength

Glass laminates, fabricated to include periodic thin layers containing biaxial compressive stresses, exhibit a threshold strength, i.e., a stress below which failure will not occur. Ion-exchange treatments in KNO₃ at 350°–450°C for periods of 3–72 h were used to create residual compressive stresses at the surface of soda lime silicate glass sheets. Wafer direct bonding of the ion-exchanged glass sheets resulted in glass laminates with thin layers of compressive stress adjacent to the glass interface and perpendicular to the laminate top surface. Critical strain energy release measurements of the bonded interface were used to optimize the bonding temperature/time to avoid significant relaxation of the stress produced by ion exchange. Stress profiles, determined via the wafer curvature measurement method, showed a residual compressive stress maximum of 328 MPa for an ion exchange temperature of 450°C. The threshold flexural strength of the ion exchanged glass laminates was determined to be 112 MPa after the introduction of indentation cracks with indent loads ranging from 1 to 5 kg. In contrast to similar ceramic laminates, where cracks either propagate across the compressive layer or bifurcate within the compressive layer, the cracks in the glass laminates were deflected along the interface between the bonded sheets.     

Modeling birefringence in SiO2 glass fiber using surface stress relaxation

The retardance of silica glass fibers was evaluated using photoelastic techniques. Here, surface birefringence in glass fibers is shown to be a consequence of surface stress relaxation for as-received fibers drawn from Suprasil II. The surface features of the birefringent fibers were compared to a model of the residual axial stress profile resulting from a diffusion-controlled surface stress relaxation. Additionally, a uniform birefringence in the fiber equivalent to a constant tensile stress was recognized and attributed to structural anisotropy produced during fiber drawing. The contribution of structural anisotropy to the observed birefringence remained constant as the surface features were successively etched away. Surface compressive stress generation was also observed, as retardance corresponding to a surface compressive stress was found to increase with applied tensile stress during short heat treatments. Significant features of the retardance profile in as-received silica glass fibers, with a thin surface compressive stress layer and compensating interior tensile stress, agreed with the residual stress profiles predicted by the surface stress relaxation model after correcting for this observed structural anisotropy.