CAJ | 학술논문

用高温固相反应法制备出A_2W_3O_(12) 型稀土钨酸盐材料(A=Y,Er,Ho,Yb),用室温及高温XRD测定其在不同温度下的结构、晶胞参数及晶胞体积,并用TOPSA软件对其结构进行精修.发现除HO_2W_3O_(12)外,都具有较大的负热膨胀系数.据A. W. Sleight预测,HO_2W_3O_(12)具有较大的负热膨胀特性,但本实验却发现它并没有负热膨胀性,反而具有非常大的正热膨胀系数.
용고온고상반응법제비출A_2W_3O_(12) 형희토오산염재료(A=Y,Er,Ho,Yb),용실온급고온XRD측정기재불동온도하적결구、정포삼수급정포체적,병용TOPSA연건대기결구진행정수.발현제HO_2W_3O_(12)외,도구유교대적부열팽창계수.거A. W. Sleight예측,HO_2W_3O_(12)구유교대적부열팽창특성,단본실험각발현타병몰유부열팽창성,반이구유비상대적정열팽창계수.
A_2W_3O_(12)(A=Y, Er, Ho, Yb) rare-earth tungstate materials were synthesized by solid state method at high temperature. The structures, lattice constants and cell volumes of A_2W_3O_(12) were determined by room temperature and high temperature XRD at different temperatures, and their Rietveld refinements were performed by TOPAS software. It is found that Y_2W_3O_(12), Er2W_3O_(12) and Yb_2W_3O_(12) all possess orthorhombic structure and show negative thermal expansion; whereas HO_2W_3O_(12) has monoclinic structure and shows positive thermal expansion. According to A. W. Sleight prediction, HO_2W_3O_(12) should have large negative thermal expansion, but it shows no negative thermal expansion but large positive thermal expansion coefficient in the present experiment.