MANUFACTURE OF POLYCRYSTAL ALUMINA SEMITRANSPARENT BODY

摘要

The in-line transmission of a translucent polycrystalline alumina arc tube for a high-pressure sodium discharge lamp is improved by as much as 50% by dipping the "green" tubular compact in an aqueous slurry containing finely-divided alumina particles and, after the slurry-dipped compact has been dried, subjecting it to the usual pre-sintering and sintering operations required to convert the compact into a dense ceramic body. The slurry is preferably prepared from the same slurry which contains the blended alumina powder, magnesia and other additives that comprise the raw-mix slurry which is spray-dried to produce the larger size generally spherical particles that are compressed or extruded to form the green compact.