Simultaneous surface and bulk crystallization of Bi sub xmlns='http://www.wiley.com/namespaces/wiley'1.5/sub1.5 ZnNb sub xmlns='http://www.wiley.com/namespaces/wiley'1.5/sub1.5 O sub xmlns='http://www.wiley.com/namespaces/wiley'7/sub7 ‐type pyrochlores and related crystals in glasses

摘要

Abstract New glasses based on the systems of Bi 2 O 3 ‐ZnO‐Nb 2 O 5 ‐B 2 O 3 and ‐GeO 2 were synthesized using a conventional melt‐quenching method, and the formation behavior of pyrochlore‐type Bi 1.5 ZnNb 1.5 O 7 crystals was examined to develop new dielectric glass‐ceramics. It was demonstrated that pyrochlore‐type Bi 1.5 ZnNb 1.5 O 7 crystals are formed in 15Bi 2 O 3 ‐20ZnO‐15Nb 2 O 5 ‐50B 2 O 3 glass, ie, pseudo‐binary Bi 1.5 ZnNb 1.5 O 7 ‐B 2 O 3 glass. The formation of a new crystalline phase consisting of mainly Bi 2 O 3 and Nb 2 O 5 was detected in 15Bi 2 O 3 ‐20ZnO‐15Nb 2 O 5 ‐50GeO 2 glass, in which a simultaneous crystallization of new crystals with different morphologies was found at the surface and in the inside of the glass. The crystallized sample of 21Bi 2 O 3 ‐28ZnO‐21Nb