Al掺杂La10(SiO4)6O3的制备及其导电性能

Synthesis and Conducting Properties of Al-doped La_(10)(SiO_4)_6O_3

以溶胶-凝胶法在850℃制备了Al掺杂La10(SiO4)6O3,即La10(SiO4)6-x(AlO4)xO3-0.5x(x=0,0.5,1.0,1.5和2.0),通过TG-DTA、XRD、IR和SEM表征,所得产品为磷灰石相。以电化学阻抗谱研究了其导电性能,发现决定电导率大小的因素有两种,一是间隙氧的数量,二是晶胞的大小,两种因素的综合作用,使得Al掺杂0.5时La10(SiO4)5.5(AlO4)0.5O2.75的电导率最大,在700℃时其电导率达到1.88×10-2S·cm-1。氧分压对电导率的研究表明,其主要的电荷载体是O2-离子。

The Al-doped La10（SiO4）6O3, namely La10（SiO4）6-x（AlO4）xO3-0.5x （x=0, 0.5, 1.0, 1.5 and 2）, was synthesized via a sol-gel method at 850 ℃. The apatite phases were characterized by TG-DTA, XRD, IR and SEM, and conducting properties were studied by electrochemical impedance spectroscopy（EIS）. It is found that the conductivity depends on both the interstitial oxygen concentration and the volume of the unit cell. The conductivity of La10（SiO4）55（AlO4）0.5O2.75 1.88×10^-2 S.cm^-1 at 700 ℃ is the highest among all the synthesized oxyapatites due to the combined effect of the interstitial oxygen concentration and the volume of a unit cell. The dependence of electrical conductivity on oxygen partial pressure indicates that the charge carriers of the silicate oxyapatite are oxygen ions.