Title: Strengthening of borosilicate glass by controlled crystallisation for lightweight bulletproof materials

Authors: Gyu-In Shim; Cheol-Young Kim; Se-Young Choi

Addresses: School of Advanced Materials Science and Engineering, Yonsei University, 2nd Engineering Building B318, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Korea ' School of Advanced Materials Science and Engineering, Yonsei University, 2nd Engineering Building B318, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Korea ' School of Advanced Materials Science and Engineering, Yonsei University, 2nd Engineering Building B318, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Korea

Abstract: For development of lightweight bulletproof glass window, TiO2 added as a nucleating agent to borosilicate glass was crystallised by 2-step heat-treatment. The glass transition temperature (Tg) and crystallisation temperature (Tc) were 595°C, 810°C, respectively. The maximum nucleation rate was 7.3 × 1010 mm−3 hr−1 at 600°C and the maximum crystal growth speed was 1.73nm/min at 810°C. The maximum 3-point bending strength was 563 MPa when the crystal volume fraction and crystal size were 36.1%, 53.4nm with number of crystals per unit volume of 4.525 × 1010 mm−3 at 600°C for 1 hr, 810°C for 30 min. The Vickers' hardness and fracture toughness of same crystal volume fraction were 736kg/mm2 and 1.0779 MPa m1/2 which were about 220%, 17%, 44% higher than borosilicate glass. Thus, the bulletproof materials were replaced by crystallised borosilicate glass, which can be expected to be thinner and lightweight.

Keywords: crystallisation; borosilicate glass; nucleating agents; TiO2; titania; titanium dioxide; glass strengthening; lightweight materials; bulletproof materials; crystal growth speed; bending strength; hardness; fracture toughness.

DOI: 10.1504/IJNT.2013.054205

International Journal of Nanotechnology, 2013 Vol.10 No.8/9, pp.632 - 642

Available online: 30 May 2013 *

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