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Synthesis and Thermal Expansion of MZr 4 P 6 O 24 (M=Mg, Ca, Sr, Ba)
Author(s) -
Limaye S. Y.,
Agrawal D. K.,
Mckinstry H. A.
Publication year - 1987
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1987.tb04884.x
Subject(s) - thermal expansion , anisotropy , materials science , atmospheric temperature range , scanning electron microscope , microstructure , negative thermal expansion , analytical chemistry (journal) , thermal , oxide , mineralogy , chemistry , composite material , thermodynamics , metallurgy , optics , chromatography , physics
MZr 4 P 6 O 24 (M=Mg, Ca, Sr, Ba), which belongs to a new, low‐thermal‐expansion family of materials known as [NZP] or [CTP], were synthesized by solid‐state reaction (oxide mixing) and sol‐gel methods, and their sinterability in two cases was investigated and compared. Thermal‐expansion measurements were made on sintered samples by dilatometry, high‐temperature X‐ray diffractometry, and the laser speckle technique. An anisotropy in axial thermal‐expansion coefficients was observed in these materials. CaZr 4 P 6 O 24 and SrZ 4 P 6 O 24 showed reverse anisotropy as well as opposite bulk thermal expansion; i.e., CaZr 4 P 6 O 24 had negative bulk thermal expansion and SrZr 4 P 6 O 24 positive bulk thermal expansion in the temperature range 25° to 500°C. The microstructure of the sintered samples was also examined by scanning electron microscopy.