| Aluminosilicate glass has excellent mechanical properties, optical properties andchemical toughened properties. After ion exchange, aluminosilicate glass has aremarkble enhancement effect, and even remains high machinery strength in the caseof thinning, which makes aluminosilicate glass a hot study subject in the frontierdisplines.Several commercially available aluminosilicate flate glasses with differentaluminum contents were used in this paper. They were treated below glass transitiontemperature (Tg) by the method of ion exchange. The surface compressive stress (CS),depth of stress layer (DOL), flexural strength (σBb) and micro hardness (Hv) test,combined with the micro-measurements such as XPS and EDS, were applied toexplore the effect of glass composition, molten salt ingredients and ion exchangesystem on the enhancement. And the enhancement effect of one-step method andtwo-step method were compared. What`s more, the effect of heat treatment onperforemance of the ion exchange glass was discussed. The results show that:1. The influence of glass composition on exchange-enhancing Thealuminosilicate glass with Al2O3≥5.5wt.%，Na2O≥12wt.%, and Na2O> K2O(wt.%) hasa good ion exchange performance. The surface compressive stress (CS) can reachmore than940MPa, and the depth of the stress layer (DOL) is above120μm. Seenfrom the analysis of ion distribution by XPS and EDS, high-alkali aluminosilicateglass has larger exchange capacity and deeper exchange depth.2.The optimum molten salt formula When high-alkali aluminosilicate glass (E#)is exchanged for6h at the temperature of440℃, the optimum molten salt formulationis the KNO3:K2CO3: Al2O3: Diatomite=100:4:1.5:2(wt.%), and the flexural strengthcan reach853.12MPa, which is1.6times of the flexural strength (532.54MPa) ofexchanged glass with no additives in the molten salt.3. The influence of exchange conditions on performance-enhancing When theoriginal glasses are exchanged by one-step method，time and temperature affectsignificantly the reinforced effect. With prolonging the exchange time and increasingthe temperature, the surface compressive stress first increase and then decrease and the depth of stress layer increase gradually. The mechanical properties of toughenedglass are related to both the surface compressive stress and the depth of stress layer.When the exchange temperature and time is appropriate, the higher surfacecompressive stress and deeper depth of stress layer can be gained at the same time,which helps improve the strength of glass. The optimum range of exchangetemperature is420~460℃and time is8~12hfor aluminosilicate glass.4. Comparation between one-step method and two-step method Thecompressive stress surface，depth of stress layer and mechanical properties oftwo-step ion exchange are larger than one step. The two-step method, which first isconducted short-term treatment at high temperature (490℃3h) to obtain deep stresslayer and then long time treatment at low temperature (400℃15h) to get high surfacecompressive stress, making bigger surface compressive stress and deeper depth ofstress layer are obtained at the same time, and the mechanical properties are improved.Moreover, the dispersion of glass strength decrease and glass be more stable.5. Effect of heat treatment on the performance of ion exchange propertiesstrengthened glass When the ion exchanged strengthened aluminosilicate glass istreated at high temperature, the results show that the maximum temperature it canbear is360℃. |
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