| 摘要 |
Pyrochlore related cpds. corresponding to Sn (2+)2.xTay3Nby2Sny(4+)y1O7-x-y1/2, where x=0-0.55; y3=0-2; y2=0-2; y1=0-0.5; y1+y2+y3=2, are prepd. by firing finely divided particles of SnO and Ta2O5 and/or Nb2O5 in a nonoxidising atmos. at least 500 deg.C, pref. 500-1100 deg.C. A conductive phase for resistors contg. a pyrochlore related cpd. as above is prepd. by firing a mixt. of SnO, SnO2, M2O5 where M is Ta and/or Nb, having a mole ratio SnO:M2O5 1.4-3.0 and SnO2 in stoichiometric excess of SnO and M2O5 and comprising 20-95 wt.% total oxides, in a nonoxidising atmos. at at least 900 deg.C. Alternatively, the conductive phase is prepd. by firing in nonoxidising atmos. a mixt. of 20-95 wt.% finely divided SnO2 and the pyrochlore related cpd.. |
