Fabrication of High Strength Transparent Bulletproof Materials by Ion Exchanged Borosilicate Glass

Kim, Young-Hwan; Shim, Gyu-In; Lim, Jae-Min; Choi, Se-Young

Journal of the Korea Institute of Military Science and Technology 2010;13(6):1121-1126.

Young-Hwan Kim, Gyu-In Shim, Jae-Min Lim, Se-Young Choi

Yonsei University

보로실리케이트 유리의 이온교환에 의한 고강도 투명방탄소재의 제조

김영환, 심규인, 임재민, 최세영

연세대학교

Abstract

Borosilicate glass (81% $SiO_2$-2% $Al_2O_3$-13% $B_2O_3$-4% $Na_2O_3$) was prepared, and the glass was ion exchanged in $KNO_3$ powder containing different temperature and time. The $K^+-Na^+$ ion exchange takes place at the glass surface and creates compressed stress, which raise the mechanical strength of the glass. The depth profile of $Na^+$ and $K^+$ was observed by electron probe micro analyzer. With the increasing heat-treatment time from 0min to 20min, the depth profile was increased from 17.1um to 29.4um, but mechanical properties were decreased. It was also found out that excessive heat treatment brings stress relaxation. The Vickers hardness, Fracture Toughness and bending strength of ion exchanged samples at $570^{circ}C$ for 10min were $821.8H_v$, $1.3404MPa{cdot}m^{1/2}$, and 953MPa, which is about 120%, 180%, and 450% higher than parent borosilicate glass, respectively. Transmittance was analyzed by UV-VIS-NIR spectrophotometer. Transmittance of ion exchanged borosilicate glass was decreased slightly at visible-range. It can be expected that transparent bulletproof materials in more light-weight and thinner by ion exchanged borosilicate glass.

Key Words: Borosilicate Glass, Ion Exchange, Electron Probe Micro Analyzer, Transmittance