Continuous polycrystalline aluminium oxide yarns - by extruding suspension of alumina in aluminium salt soln. winding and heating

摘要

Continuous polycrystalline aluminium oxide yarns for reinforcing metals and plastics, e.g. helicopter rotors and printed circuit plates, are produced by (a) extruding a mixt. consisting of solid particles in an aqs. phase, >=80 wt % of the particles consisting of aluminium oxide, and the aqs. phase contg. a basic Al salt, through a multiplicity of openings to form a multifilament yarn contg. 30-60 wt % volatile components, (b) winding the yarn on a compressible spool to form a shrinkable package, (c) heating the package to 300-1400 degrees C to reduce the amt. of volatile components in the yarn to less than 11 wt % (d) winding the yarn from the package, and (e) heating the yarn to 1000-1500 esp. 1300-1500 degrees C, in order to convert the salts to oxide. Product has good strength and resistance to high temps.