Research/Patents/US 4910172
US 4910172Tier 3 — General Defense

PREPARATION OF MULLITE WHISKERS FROM A1F3, SI02, AND A1203 POWDERS

Assignee

US Government

Filed as: UNITED STATES OF AMERICA, THE, AS REPRESENTED BY THE SECRETARY OF THE NAVY

Filed

Feb 8, 1989

Granted

Mar 20, 1990

Location

SILVER SPRING MD US

Abstract

A process for preparing mullite whiskers by (1) forming an anhydrous, intimate, uniform mixture of AlF3, Al2O3, and fused SiO2 powders in an amount selected to produce stoichiometric mullite or a solid solution of Al2O3 in stoichiometric mullite; (2) heating the mixture in anhydrous SiF4 atmosphere at a temperature of from about 700 DEG to about 950 DEG C. to form barlike topaz crystals; (3) heating the barlike topaz in an anhydrous SiF4 atmosphere a a temperature of from about 1150 DEG C. to about 1700 DEG C. to produce the mullite whiskers.

Source: Google Patents

35 USC §181 Secrecy Order

Imposed

Apr 13, 1989

Rescinded

Jun 28, 1989

Duration

2 months

Inventor

  • 1INNA G. TALMY
Back to patent indexSource: USPTO 35 USC §181 secrecy order records