Synthesis and property evaluation of novel nano spinel glass-ceramics for armor and photonic applications

• Grant number: 14/20865-9
• Support Opportunities: Research Grants - Visiting Researcher Grant - International
• Start date: February 23, 2015
• End date: August 25, 2015
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Ana Candida Martins Rodrigues
• Grantee: Ana Candida Martins Rodrigues
• Visiting researcher: Atiar Rahaman Molla
• Visiting researcher institution: Central Glass and Ceramic Research Institute (CGCRI), India
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated research grant: 13/07793-6 - CEPIV - Center for Teaching, Research and Innovation in Glass, AP.CEPID

Abstract

Certain glasses, when crystallized by a simple heat treatment, form very fine-grained, transparent materials. Polycrystalline materials formed in this manner have several distinct advantages over glasses and ceramics. The properties of glass-ceramics (GC) depend on composition, phase assemblage, and microstructure. The compositions and heat treatment conditions determine the potential phase assemblage, which in turn governs many physical and chemical characteristics such as mechanical properties, density, optical and thermal properties. Magnesium aluminate spinel (MgAl2O4), possessing a unique properties, such as no phase transition up to its melting point (2105ºC), high strength at elevated temperature, superior hardness, high elastic modulus, high chemical inertness against both acidic and basic slag, low thermal expansion coefficient and high thermal shock resistance, has long been considered as an important material. However, fabrication of the high purity dense MgAl2O4 spinel sintered body by conventional solid-state reaction method is often difficult. In particular, coarsening of particle size, e.g., by Ostwald ripening, is very difficult to suppress in a solid state sintering process. Fabrication of glass-ceramic, using melt quenching followed by heat-treatment is a suitable technique to obtain pore-free, fine-grained, nano-structured material, embedded in a host glass matrix. With this method, strict control over the crystallite size is possible and transparent characteristics of the host glass can be retained .The proposed research focuses on the determination of a suitable fabrication technique by optimizing the glass composition and processing parameters to obtain highly transparent, high strength spinel glass-ceramic nano-composites for application in armors. The spinel glass has, in general, exorbitantly high melting temperature of ~1700ºC which makes it difficult to fabricate homogenous, defect free glass by melt-quenching technique. The main objective of the present research is to optimize a comparatively low melting composition for synthesis of homogeneous spinel glass-ceramics and characterization of its microstructure, optical, thermal and mechanical properties in order to establish its suitability for armor and photonic applications. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

MOLLA, ATIAR R.; RODRIGUES, ALISSON M.; SINGH, SHIV PRAKASH; LANCELOTTI, RICARDO FELIPE; ZANOTTO, EDGAR D.; RODRIGUES, ANA C. M.; DOUSTI, MOHAMMAD REZA; DE CAMARGO, ANDREA S. S.; MAGON, CLAUDIO JOSE; ALMEIDA SILVA, IGOR D'ANCIAES. Crystallization, mechanical, and optical properties of transparent, nanocrystalline gahnite glass-ceramics. Journal of the American Ceramic Society, v. 100, n. 5, p. 1963-1975, MAY 2017. (14/20865-9, 13/24064-8, 13/07793-6)