PREPARATION AND USE OF MULLITE WHISKER NETWORKS

摘要

A process for producing mullite whiskers includes heating a non-stoichiometric mixture containing aluminum and silicon to a temperature within a range of 500 DEG C to 950 DEG C in the presence of SiF4 gas to form fluorotopaz and then to a temperature within a range of 800 DEG C to 1500 DEG C to convert the fluorotopaz into mullite. A mullite whisker-forming composition that procudes an interlaced network of single crystal mullite whiskers with a controlled permeability comprises a mixture of an aluminum-containing material with a silicon-containing material and a fluxing agent which melts at temperatures below 1000 DEG C. The ratio of aluminum atoms to silicon atoms in the resultant product is approximately non-stoichiometric. The network may, for example, be used to fabricate a regenerable exhaust gas filter element for diesel engines.