http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Ebbinghaus, Stefan G.,Krause, Holger,Lee, Doh-Kwon,Janek, Jü,rgen American Chemical Society 2014 Crystal Growth & Design Vol.14 No.5
<P>Single crystals of Ca<SUB>12</SUB>Al<SUB>14</SUB>O<SUB>33</SUB> (C12A7, mayenite) substituted with 1 mol % Fe were grown by the floating zone technique in an atmosphere of 2% O<SUB>2</SUB>/98% N<SUB>2</SUB>. The iron substitution leads to an increase of the unit cell parameter by roughly 0.002 Å. Optical spectroscopy reveals an additional broad absorption band at 310 nm for the iron-substituted sample reflecting the yellow color of the crystals. XANES measurements at the Fe–K absorption edge prove the incorporation of Fe<SUP>3+</SUP> on the aluminum sites. Measurements of the magnetic susceptibility resulted in a value of 5.8 μ<SUB>B</SUB> per iron ion as expected for high-spin Fe<SUP>3+</SUP>. C12A7 is known to be a very good oxygen ion conductor at high temperatures. In pure oxygen, the iron substitution leads to a slightly reduced conductivity between approximately 500 and 800 °C, while at higher temperatures, the conductivity is very similar to the pristine material. Under reducing conditions, the slope of log(σ) vs log(<I>p</I>(O<SUB>2</SUB>)) of the iron-substituted sample was found to be steeper than that for pure C12A7.</P><P>Yellow-colored single crystals of iron-substituted Ca<SUB>12</SUB>Al<SUB>14</SUB>O<SUB>33</SUB> were grown by the floating zone technique. Fe−K XANES, optical spectroscopy, and magnetic measurements prove the incorporation of 1 mol % Fe<SUP>3+</SUP> on the aluminum sites. Compared with pristine C12A7, a slightly enhanced activation energy for the oxide ion conductivity was found. At high temperatures and under reducing atmosphere, the conductivity of C12A7:Fe strongly increases.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cgdefu/2014/cgdefu.2014.14.issue-5/cg401823k/production/images/medium/cg-2013-01823k_0007.gif'></P>