Springer Online Journal Archives 1860-2000
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Abstract Ultrafine powders of cubic ZrO2 were obtained at about 270° C by heating hydrated amorphous ZrO2 in greater than 0.2 molal calcium acetate solutions. Ca2+ ions played a role as nucleii for crystallization and were introduced into distinct sites of the crystalline phases, that is, substituted for Zr4+ ions. Mn2+ ions produced almost the same effects on the crystallization of ZrO2·EPR spectra for powder samples containing Mn2+ ions apparently showed two types as follows: for tetragonal ZrO2 with a trace of monoclinic ZrO2, the central fine structure transitions (M=+1/2↔−1/2) showed a well-resolved hyperfine structure. In addition to the Δm=0 transition, forbidden Δm=±1 transitions were observed. For cubic ZrO2, the broad underlying response was observed as well as the hyperfine structure composed of six main peaks.
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