| 摘要 |
<p>Plates are obtained by impregnating an impervious sintered body of Al with Na, K or their oxides in vapour form, by heating to 1200-1700 degrees C in an atmos. contg. gaseous Na, K or their oxides. In a second stage the impregnated sintered body is again heated in the same atmos. which, however, contains a smaller amount of gaseous Na, K or their oxides, and a temp. of 1400-1800 degrees C. The plates thus treated are previous to Na and K ions. Pref. the alpha-Al sintered body is embedded in a powder mixt. consisting of Al and >30 wt.% of a Na cpd. which when heated forms the required gaseous atmos., and in a second stage is embedded in a powder mixt. which contains 10 wt.% of Na cpd. such as Na carbonate, and which on heating provides the required atmos. for impregnation.</p> |
