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Effect of Substituent Ions on Martensitic Transformation Temperatures in Dicalcium Silicate Solid Solutions
Author(s) -
Fukuda Koichiro,
Taguchi Hiroyuki,
Fukuda Tetsuya
Publication year - 2002
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.1151-2916.2002.tb00356.x
Subject(s) - ionic radius , silicate , solid solution , diffusionless transformation , ion , phase (matter) , materials science , substituent , crystallography , ionic bonding , transformation (genetics) , analytical chemistry (journal) , chemistry , mineralogy , martensite , stereochemistry , metallurgy , microstructure , organic chemistry , biochemistry , gene
Five types of Ca 2 SiO 4 solid solutions, doped with either P 5+ , Ge 4+ , Fe 3+ , Mg 2+ , or Ba 2+ , were prepared and examined by high‐temperature X‐ray diffractometry up to 800°C. The starting and finishing temperatures were determined for the α′ L ‐to‐β martensitic transformation during cooling and the reverse (β‐to‐α′ L ) transformation during heating. These four types of transformation temperatures for the preparations doped with either P 5+ or Ge 4+ steadily decreased with increasing substituted fraction. The effect of the substitution on the decrease for each transformation temperature was quantitatively evaluated by Δ T / x , where Δ T is the difference in the transformation temperatures between the solid solutions and pure Ca 2 SiO 4 , and x represents the fraction substituted for Si 4+ or Ca 2+ in the α′ L ‐phase structure. The evaluated value for the substitution of P 5+ was more than 3 times that of Ge 4+ . The effect of the substituent ions mentioned above, together with Na + and Sr 2+ , on the lowering of the starting temperature of the α′ L ‐to‐β transformation was principally determined by the differences in the ionic radius between the interchanging cations.