离子交换工艺对ESP玻璃的影响

使用两步离子交换法制备工程应力分布玻璃( ESP玻璃)。两步离子交换中第一步交换时间较长,第二步交换时间较短。主要研究经过不同第一步离子交换工艺制度后的ESP玻璃性能上的区别。本文对ESP玻璃测试了弯曲强度,显微硬度,K+分布状态,并根据弯曲强度,K+分布状态计算得出Weibull模量以及离子扩散系数。结果表明：第二步离子交换会降低第一步离子交换玻璃的弯曲强度,而两步离子交换后的ESP玻璃其Weibull模量有所升高。显微硬度趋势与弯曲强度趋势一致。结合抗折强度以及K+分布状态,可知第一步离子交换最佳温度为450℃,时间30 h;第二步离子交换最佳温度为400℃,时间33 min。     

第二步离子交换时间对钠铝硅系统力学敏感玻璃的影响

采用低温型两步离子交换法对钠铝硅系统玻璃进行钢化处理制备出工程应力玻璃(ESP玻璃).第一步钢化采用长时间高温处理,第二步钢化采用短时间低温处理.研究了钢化玻璃中第二步钢化处理的交换时间对弯曲强度,Weibull模数,K+、Na+离子扩散等的影响.结果表明:随着第二步交换时间延长,弯曲强度和Weibull模数先增加后下降,在30 min时达到最大值.K+离子富集峰位置逐渐向玻璃内部移动,Na+离子富集峰位置逐渐增大,宽度也逐渐增大.ESP玻璃较一步钢化玻璃有更高的弯曲强度,钾离子富集峰位置更深.     

玻璃表面化学增强技术

玻璃的理论强度很高,但由于原料组成、熔化、成形和退火等各工艺过程的影响,玻璃的实际强度比理论值要低很多。采用表面化学增强技术,能够降低玻璃的表面缺陷,提升玻璃的力学强度、表面硬度、耐划伤等性能。玻璃表面化学增强技术有离子交换法、表面化学抛光、脱碱增强法、表面涂层增强、表面微晶化增强技术等方法,通过对上述方法的研究和对比分析,每种方法都有各自相应的特点和应用范围,这些方法拓宽了玻璃表面化学增强技术的研究和发展。     

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。     

离子交换增强玻璃研究进展

多年来,人们一直在研究提高玻璃强度的途径,利用离子交换增强技术对普通平板玻璃进行增强处理后得到了非常好的增强效果。本文总结了离子交换的工艺方法,并介绍了国内外对玻璃进行离子交换增强的研究进展与成果。     

RO-Al_2O_3-SiO_2玻璃的钢化与力学性能(英文)

采用熔融法制备出了无碱型RO-Al2O3-SiO2玻璃.研究了残余应力、钢化工艺以及样品尺寸对RO-Al2O3-SiO2玻璃的弹性模量、剪切摸量、维氏硬度、弯曲强度和断裂韧性等力学性能的影响.结果表明:合适的钢化工艺和残余应力可以显著提高其弯曲强度和断裂韧性,但对其它力学性能影响较小.经钢化处理后的RO-Al2O3-SiO2玻璃的弯曲强度和断裂韧性分别达到了263 MPa和2.28MPa·m1/2.与没有经钢化处理的玻璃样品相比,分别提高到了4倍和235%.提出了1种新型的钢化工艺--非对称钢化工艺,对于在非对称载荷下服役的玻璃构件来说,非对称钢化工艺有可能在提高玻璃力学性能的同时还可以降低其自爆风险.     

金属氧化物增强封接玻璃的研究

依据封接的物理相容性与化学相容性,制备了两种添加有微量金属氧化物的改性DM-308型电子玻璃,研究了添加的金属氧化物对玻璃与可伐合金结合性能的影响.结果表明:添加微量的金属氧化物可以不同程度地提高玻璃与可伐合金的结合强度;非界面处玻璃中气孔率的降低以及玻璃化学键键性的改变是增强的主要机理.     

空心玻璃微珠增强聚四氟乙烯复合材料的制备及拉伸强度的研究

研究了空心玻璃微珠增强聚四氟乙烯复合材料的拉伸强度的变化。研究表明：复合材料的拉伸强度与空心玻璃微珠含量、烧结工艺条件和偶联剂的种类有关；用复合偶联剂处理过的玻璃微珠填充树脂，改善了微珠与树脂的相容性及分散性，从而提高了材料的拉伸强度。并对材料的拉伸强度进行了理论预测。     

高强度超薄玻璃波纹板的制备及化学增强

随着超薄玻璃在手机、显示器等电子产品上的广泛应用,未来曲面异形、高强度、多功能化是其主流发展方向.超薄玻璃波纹板作为一种多曲面弯曲玻璃,其制造难度大,强度低.对超薄玻璃波纹板的热弯和化学增强技术进行研究,成功制备了高强度超薄玻璃波纹板,对超薄曲面玻璃热弯及增强技术的发展具有一定的指导意义.     

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.     

化学强化玻璃的发展现状及研究展望

化学强化玻璃因其表面压应力层使玻璃的机械强度提高,被广泛用于电子产品显示屏领域。本文对钠钙玻璃、铝硅玻璃、磷铝硅玻璃、锂铝硅玻璃等的化学强化进行了综述,对进一步通过优化骨干网络结构来提高玻璃本征强度获得更高机械强度的玻璃做出了可行性探索。总结了目前化学强化玻璃面临的问题及发展方向,为相关科学研究和工业生产提供参考。     

Prediction of crack propagation and fracture in residually stressed glass as a function of the stress profile and flaw size distribution

Engineered stress profile (ESP) glasses are noted for narrow strength distributions and the potential for stable growth of multiple surface cracks under applied tensile stress. This behavior depends on the interaction of the surface flaw size distribution with the residual stress profile in the material. In this work, several surface preparation methods were used to produce a range of flaw size distributions in soda lime silica glass specimens. Two ion exchange processes were then performed on these specimens to produce ESP glass. For each condition, crack growth behavior and fracture strength were experimentally observed. Residual stress profiles resulting from each ion exchange process were measured with an optical technique. These stress profiles were used to calculate stress intensity factors as a function of crack geometry, using a weight function method. Crack growth and fracture strength predictions based on these stress intensity factors were compared to experimental data, resulting in good agreement in most cases.     

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。     

A comparative study on the effect of loading speed and surface scratches on the flexural strength of aluminosilicate glass: Annealed vs. chemically strengthened

Quasi-static and dynamic three-point-bending experiments were conducted on both annealed and chemically strengthened aluminosilicate glass scratched by different normal loads. Scratched areas were observed by optical microscope and atomic force microscope. Chemically strengthened glass shows better resistance to surface scratch. These dynamic experiments were carried out using a modified Split Hopkinson Pressure Bar (SHPB) device and a pulse-shaping technique was used to keep constant loading speed to the specimens. In tests, high-speed photography was also used to observe the failure process of the specimens. The test results showed that the flexural strength of aluminosilicate glass (AG) strongly depends on the applied loading speed. Compared with its annealed counterpart, the chemically strengthened glass (CSG) showed higher flexural strength to both static and dynamic loadings. Moreover, the three-point bending experiments were conducted on scratched AG and CSG specimens and decrease of 20–40% in flexural strength was observed. The fractography analysis showed that in dynamic loading conditions the fracture surface was not smooth and has more secondary cracks as compared to static loading.     

Effects of chicken eggshell filler size on the processing,mechanical and thermal properties of PVC matrix composite

The effects of filler particle size of poly(vinyl chloride)/chicken eggshell powder (PVC/ESP) composites on the processing, tensile properties, morphology and thermal degradation were investigated. The mixing of composites was done using Rheomix internal mixer. The processing torque of PVC/ESP composite at a particle of 0.2 μm exhibits lower processing torque compared to that at a particle size of 7 μm due to the dispersive resistance from larger ESP filler particles. Good interfacial adhesion exists between the filler and matrix in composites prepared via a filler particle size of 0.2 μm, which has improved the tensile strength and modulus of PVC/ESP composite compared to a filler particle size of 7 μm as justified from FESEM images on the tensile fracture surface of the composites. Thermogravimetric analysis results show that the filler particle size of 0.2 μm composite exhibits higher thermal stability compared to the filler particle size of 7 μm composite.     

离子交换增强玻璃表面化学稳定性的研究

系统研究了化学钢化及盐溶液后处理对Na2O-CaO-SiO2玻璃表面化学稳定性的影响。详细考察了用熔融KNO3化学钢化的玻璃以及用适当盐溶液后处理的化学钢化玻璃,在受水侵蚀后R2O的沥滤量和失重以及受碱侵蚀后SiO2的溶出量和失重。结果表明,用熔融KNO3对玻璃进行钢化处理后,玻璃的耐水性和耐碱性均有明显下降。而将化学钢化的玻璃利用适当盐溶液处理后,可以改善钢化玻璃的化学稳定性,因而可以进一步提高化学钢化玻璃的使用性能和拓展其使用范围。     

Effect of normal scratch load and HF etching on the mechanical behavior of annealed and chemically strengthened aluminosilicate glass

Micro-cracks generated by hard body scratch are a major cause of strength decrease for silicate glass. The influence of normal scratch load on the cracking patterns and flexural strength of annealed glass (AG) and chemically strengthened glass (CSG) were studied. With the increase of the normal load, the load capacity of scratched AG specimens decreased to about 40 MPa at 20gf immediately. However, the residual strength of CSG decreased to a steady value of 145 MPa as the scratch load increased to 500gf. Then the effect of hydrofluoric acid (HF) etching on the surface morphology and mechanical properties of the 500gf scratched glass were investigated. After 8min (for CSG) and 16 min (for AG) acid treatment, the flexural strength of CSG and AG increased to a considerable value of 900 MPa, which is 3.6 and 5.5 times higher than the flexural strength of undamaged specimens. Microscopic observations show that the blunting and eliminating of median cracks as well as the formation of new surfaces are the main causes of strength enhancement.