Continuous development of advanced technologies brings about the constant need for new materials with suitable properties to even stricter demands. A special interest has been given to the development of inorganic transparent materials, not only for optical and lighting applications, but also in the electronic, aerospace, civil construction and armour industries. The major motivations are generally weight reduction and enhancement of mechanical properties, also at high temperatures, while simultaneously keeping or, in some cases, increasing the optical transparency. A review of the latest industrial developments in the field of transparent inorganic materials is presented in this paper. Relevant patents disclosed for polycrystalline ceramics, glass-ceramics and composites, in which transparency is claimed as one of the main properties achieved, are described and discussed. Only fully inorganic materials have been considered, therefore, in the case of composite materials, laminate systems including polymeric layers (commonly used in armour applications or security glass) were not included in the review. Moreover, focus is on structural applications, while optical and telecommunication-related materials are not covered in detail.
Transparent ceramics, glass-ceramics, composites, inorganic materials, armour, electro-optical devices, polycrystalline alumina, aluminum oxynitride, perovskites, yttrium aluminum garnet
Department of Materials,Imperial College London, Prince Consort Road, London SW7 2AZ, UK.