Читать книгу Encyclopedia of Glass Science, Technology, History, and Culture - Группа авторов - Страница 134

As named for its alkali‐resistant properties, AR‐glass fiber was invented in the mid‐1960s and first commercialized by Pilkington Brothers in the United Kingdom in the early 1970s under the trade name Cem‐Fil®. It was presented as a glass fiber option for reinforcing concrete structures. The glass chemistry was actually developed by a chemist at the Building Research Establishment and licensed to Pilkington by the National Research and Development Corporation, leading to its initial commercial application. The glass chemistry is primarily comprised of Na₂O, CaO, ZrO₂, and SiO₂ with a small amount of Al₂O₃. The higher Al₂O₃ found in most commercial glass fibers results in lower ZrO₂ solubility. Unlike E‐CR fibers, AR‐glass fiber offers high resistance to alkaline corrosion as well as to acid corrosion. This resistance is attributed to the formation of a protective layer rich in ZrO₂ on the fiber surface in corrosive media. Because of the relatively high Na₂O and low Al₂O₃ levels, the fiber modulus and tensile strength are lower than for E‐glass fibers despite the high concentration of ZrO₂. The overall higher production and material cost of AR‐glass limits its utility to challenging fiber applications in cement reinforcement. Current developments are focused on increasing ZrO₂ solubility to improve further corrosion resistance and to improve melting and fiber‐forming costs.