Microwave heat treatment of articles, e.g. of refractory material - with avoidance of plasma formation near article being treated, increasing speed of treatment and possibly higher temps.

摘要

Process for thermal treatment of an article by microwaves includes avoiding the formation of plasma in the neighbourhood of the article. The formation of plasma may be avoided by e.g. limiting the power emitted by the micro-wave source; by using a current of neutral gas, e.g. air, N2, Ar, He; by creating near the article an electro-magnetic blow-out of the plasma; or by maintaining a partial vacuum. The treatment can be more rapid and higher temps. can be reached than in existing processes. Typically, with an installation for treating refractory materials, according to existing technique the power delivered is =700 W. By avoiding the formation of plasma it is possible to deliver 1.5kW.