Inorganic fibres and microfabricated parts by laser assisted chemical vapour deposition (LCVD): Structures and properties

Abstract

Laser assisted chemical vapour deposition (LCVD) is a new generic process for fabricating advanced inorganic fibres, as well as three-dimensional microsprings and solenoid, directly from the vapour phase. Using high reactor pressures (> 1 bar) and a unique rate control mechanism, chemically pure and structurally uniform boron, carbon, silicon, silicon nitride and carbide, and germanium fibres with small diameters (> 6 μm) and high growth rates (0.3–1.1 mm/s) were obtained. Among others, ultra strong (> 7.5 GPa) boron and stoichiometric silicon carbide fibres were obtained, as well as highly flexible carbon fibres representing a new form of carbon. This paper deals with structure-property relationships relative to market requirements. Growth rates and process economics are comparable to those by which commercial sapphire fibres are obtained from the melt. The process promises to afford new continuous single crystal fibres (including silicon and tantalum carbide) for structural composites uses at temperatures ranging from 1500 to 2200 °C, new sensor fibres (including ZnSe) and fibres for consumable high temperature sensor systems.