Continuous Oxide Filament Synthesis (Devitrification).
Technical documentary rept. May 69-Apr 70,
BOEING AEROSPACE CO SEATTLE WA
Pagination or Media Count:
Studies to produce continuous aluminum oxide filaments by vacuo-thermal conversion of precursor aluminum-boro-phosphate glass filaments are described. A field of compositions in the ternary Al2O3.B2O3.P2O5 system on or near the join line between the Al2O3, AlPO4 eutectic and B2O3 having alumina concentrations ranging from 40 to 55 percent were identified that form clear glasses when roll quenched. The feasibility of continuously drawing glass filaments from a 40Al2O3.40B2O3.20P2O5 melt was demonstrated. Filaments of this composition have been converted to alpha alumina filaments by vacuo-thermal treatment. Macro-warpage and microkinking associated with the thermal conversion were eliminated by tensioning the filaments during conversion. The tensile strength of converted filaments in the presently developed state are low 5 to 30 ksi because of microcracks. Further work is planned to optimize the conversion process to eliminate microcracks and control grain growth. Author
- Refractory Fibers