ZrO 2 Nanopowders Doped with Eu: SEM, XRD and UV Spectroscopy Studies
- PDF / 252,123 Bytes
- 5 Pages / 432 x 648 pts Page_size
- 77 Downloads / 160 Views
ZrO2 Nanopowders Doped with Eu: SEM, XRD and UV Spectroscopy Studies Gerardo Villa Sánchez1,2, Demetrio Mendoza Anaya1, Emmanuel Palma Palma1,3, Claudia E. Gutiérrez Wing1, Raúl Pérez Hernández1, Oscar F. Olea Mejía2, Federico García Santibañez3 1. Instituto Nacional de Investigaciones Nucleares; Carr. México-Toluca s/n La Marquesa, Ocoyoacac, Edo. de Mexico C.P. 52750, Mexico. 2. Facultad de Química, UAEMex. Paseo Colón y Tollocan, Toluca, México 50110, México. 3. Facultad de Ciencias, UAEMex. El Cerrillo Piedras Blancas, Toluca, Edo. de México. E-mail: [email protected] ABSTRACT Zirconia nanopowders doped with different concentrations of Eu were prepared by the solgel method followed by a thermal treatment at 500qC. Morphological and crystallographic characteristics were studied by scanning electron microscopy, X-Ray diffraction and UV spectroscopoy. Results showed a modification of the size of nanopowder particles when the concentration of Eu is increased from 0.0 to 4.0 wt%. Also, at lower concentration of Eu the tetragonal ZrO2 is the most abundant phase while high concentrations of Eu lead to the formation of the monoclinic phase. The UV spectroscopy of ZrO2 samples shows two main absorption peaks at 228 and 214 nm. The novel characteristics of the ZrO2 nanopowders doped with Eu allow us to propose them for use as solar UV radiation detectors. INTRODUCTION ZrO2 is an important ceramic material used for a variety of applications. It has three polymorphic variants: monoclinic, tetragonal and cubic [1,2]. The martensitic transformation tetragonal (t-ZrO2) to monoclinic (m-ZrO2) zirconia leads to about 3% volume expansion, which may lead to catastrophic failure of the system [3]. To increase its applicability, extensive work has been carried out to retain the high temperature forms of zirconia at room temperature. Among the methods of stabilizing higher temperature forms of ZrO2, the most common is the use of additives; these include the addition of dopants or the use of soft-chemistry methods from which nanocrystalline materials can be obtained. Among these, ZrO2 is a potential selection for being the host for rare earth ions in the field of photonics due to their superior electrical, chemical and mechanical characteristics. Recently, a considerable amount of work has been reported on the properties of rare earth-doped ZrO2 [4]. One of the fields in which pure and rare earth doped zirconia have been widely used is in radiation physics to detect and quantify ionizant radiation through their thermoluminescent (TL) signal. In this work, a SEM, XRD and UV spectroscopy study on pure and Eu doped zirconia is presented. As an application, an analysis of the TL signal induced by UV solar radiation on samples is also presented. EXPERIMENTAL ZrO2 was prepared by the sol-gel technique. Zirconium propoxide was mixed with ethanol and ammonium hydroxide under vigorous stirring and increasing the mixing temperature
39
up to 85 ºC; immediately after, distilled water was added. The stirring and mixing temperature we
Data Loading...
