Marine applications of glasses and ceramics

Abstract

INTRODUCTION INOR6ANIC, non-metallic materials have found applications in marine structures for many years. Some of these materials have outstanding resistance to deterioration in the sea and are transparent. Silica-glass windows are standard items in the periscopes of submarines. Some of these materials are extremely resistant to compression stresses and are sufficiently rigid to offer high resistance to elastic buckling in thin shells under external pressure. Light-bulbs are surprisingly resistant to external pressure. Also some have low specific gravities. Hollow glass spheres are furnishing buoyancy in deep oceanography at modest cost. A number of improvements are being made in glasses and ceramics, and in their processes that improve their tensile strength, bending strength, resistance to impact and resistance to stress--corrosion cracking. Also, in the last five years, there has been a great increase in efforts to use these materials in sophisticated marine applications, such as in capsules for manned vehicles and for moored habitats, for deep submergence. The incentive is to exploit the favourable trade-offs of structures made of these materials with regard to allowable depths, buoyancy, durability and cost. These efforts on the development of materials and on their deep submergence uses are intimately conected. It has become evident that the latter goal can be attained more effectively by accelerating and exploiting the former. The purpose of this paper is to summarize advances being made in these related fields.