Synthesis of Nanocrystalline Yttrium Aluminum Garnets by Sol–Gel Combustion Process: The Influence of pH of Precursor Solution

The composition 3Y2O3.5Al2O3 commonly called yttrium alumina garnet (YAG, Y3Al5O12) possesses the cubic garnet structure is an important solid-state laser material. Single crystal YAG is obtained by the Czochralski (CZ) method wich tens of days are required to grow a large size single crystal [1]. Compared with YAG single crystals, polycrystalline YAG transparent ceramics have the advantages of being inexpensive and easy to fabricate, mass production and large size. Recently, polycrystalline YAG ceramics have received much attention and are used in lasers, cathode ray tube(CRT) , Q-Switches, field emission display(FED), vacuum fluorescent display(VFD), electro luminescent(EL) and etc. Owing to high application potential of YAG ceramics, some wet-chemical methods for the synthesis of pure and homogeneous YAG powders are adopted because of good mixing of the starting materials and excellent chemical homogeneity of the final products. Most of these methods suffer from complexity and time consuming procedures. However, gel combustion methods for synthesizing fine powders are of significant interest, primary due to the overall simplicity of the technique. Also the method can guarantee a precise control of cationic stoichiometry and homogeneous mixture of metal ions at the atomic level. The aim of this research is to study the influence of pH value of the solution on the formation of single-phase YAG powders which is prepared by serving sol-gel combustion method