Partial wet route for YAG powders synthesis leading to transparent ceramic: A core–shell solid-state reaction process

Synthesis of Y3Al5O12 (YAG) powders respectively presents morphology control and chemical stoichiometry problems when employing the solid-state reaction or the wet-chemical route. YAG powder retaining the morphology of Al2O3 powder was designed and synthesized via a partial wet-chemical process with yttrium ions precipitating on the Al2O3 particles. The formation process of the Y-compound/Al2O3 core–shell structure is discussed on the basis of zeta-potential measurements and HRTEM results. Two stages, including direct precipitation at the surface of the Al2O3 particles and the assembly of the yttrium precipitate from explosive nucleation onto the yttrium compound-coated Al2O3 particles, are proposed. A spherical surface reaction process is illustrated. A pure YAG phase can be realized at a temperature about 300 °C lower than that of the traditional solid-state reaction process.