Thermal Stability of Al2O3 Coated Low Transition Temperature Glass

Kung Jeng Ma; His Hsin  Chien; S. Prabhakar Vattikuti; Chien Huang Kuo; Cheng Bang Huo; Choung Lii Chao

doi:10.4028/www.scientific.net/DDF.297-301.875

Paper Titles

Microstructure and Hydrogenation Property of Mg-6.7 mol% Ni Alloy
p.853

Depth Resolved and Elemental Selective XRF and XAS in Surface Layer of Annealed Fe-Cr Alloys
p.859

Depth Resolved XRF and XAS for Enrichment and Oxidation of Mn on Surface of Annealed Fe-Mn Alloys
p.864

The Effect of TaN Interlayer on the Performance of Pt-Ir Protective Coatings in Glass Molding Process
p.869

Thermal Stability of Al₂O₃ Coated Low Transition Temperature Glass
p.875

Presentation of a New Method for Determination of Diffusion Coefficients of Gaseous Pollutants in Cladding Wall Materials Indoors
p.881

Macroporous Silicon Electrochemical Etching for Gas Diffusion Layers Applications: Effect of Processing Temperature
p.887

Thermal Diffusivity of Traditional and Innovative Sheet Steels
p.893

Electroless Ni-P Composites with ZrO₂: Preparation, Characterization, Thermal Treatment
p.899

HomeDefect and Diffusion ForumDefect and Diffusion Forum Vols. 297-301Thermal Stability of Al2O3 Coated Low Transition...

Thermal Stability of Al₂O₃ Coated Low Transition Temperature Glass

Abstract:

There are growing varieties of glasses available on the market for the manufacture of molded optical lenses. A glass with a low transition temperature (Tg) has the advantage of extending the service life of molding dies. However, most of the low Tg glasses have a high content of alkali metal oxides and tend to induce severe glass sticking problems. This has made the molding process of these kinds of glasses very difficult indeed. The low Tg glasses normally demonstrate poor chemical durability and scratch resistance. As a result, the yields of fabricating the glass-preforms are frequently rather low. This research tried depositing a very thin layer of aluminum oxide on various glass-preforms by a water based sol-gel process. A high temperature glass wetting experiment was carried out to investigate the high temperature interfacial reaction between the coated glass gobs and stainless steel substrate. It was found that when the uncoated glass-preforms were brought into contact with stainless steel, the contact angle decreased with increasing heating temperature and duration. Owing to the severe interfacial chemical reaction, the originally transparent glass gradually turned translucent. In the case of Al2O3 coated glass-preforms, the variation of the contact angles was very limited, which presented no sticking and no wetting behavior. No reaction products could be detected on the contact area after the wetting test. The optical transmission of those lenses molded from the coated glass-preforms exhibited no or very little changes after the molding process.