Silica Carbide Lamps:
Light From A Whisker

This incandescent lamp uses a single crystal of silica carbide for a filment rather than a tungsten wire. Another material, hafnium carbide, has also been tried in experiments.

The very thin "whisker" filament is stronger than tungsten, and has a high resistance that changes little during the lamp's operation. A major difficulty lies in growing the single crystals long enought to be useful. The crystals take time to grow and conditions in the oven must remain very stable.