Синтез иттрий-алюминиевого граната, активированного ионами церия, термохимическим методом

Abstract

Разработан метод синтеза дегидроксилированных ультрадисперсных порошков граната, легированного ионами церия (желтого люминофора), низкотемпературной термохимической реакцией.

The method of synthesis of dehydroxylated ultrafine powder of garnet doped with cerium ions (yellow phosphor) by low-temperature thermo chemical reaction is develope d. It was found that the size, structure and morphology of the particles of yttr iumaluminum garnet powders, activated by cerium ions, largely depend on the composition of the fuel mixture and the regime of subsequent heat treatment. The average size of the crystalline particles calcu lated from the data on the specific surface of the powders are in the region from 0.9 μm to 1.6 μm depending on the firing temperature (from 650 to 1200°C), and the diameter of the pr imary particles YAG:Ce (average size of the coherent scattering) is 45 nm at a firing temperature of 650°C. Powders based on YAG:Ce, synthesized by thermochemical method using a mixture of yttrium nitrates, aluminum, cerium and mixed fuel (carbamide and hexamethylenetetramine), when excited with blue light, luminesce in a wide band in the range of 470–750 nm with a center at 550 nm (yellow light). It is established that upon the preparation of YAG:Ce by thermochemical method in urea and hexamethylenetetramine develops temperature, sufficient for the formation of compounds Y3Al5O12 and entering of cerium ions in the garnet structure. The gas reducing medium formed during the thermochemical reaction contributes to the formation of Се3+ ions.