Studies of Process Parameters on Scale up of Nd:YAG Nanopowder Synthesis by Sol-gel Process

Scale up of process from 6 g to 200 g batch for preparation of phase pure Neodymium doped Yttrium Aluminum Garnet (Nd:YAG) nanopowder by sol-gel process using nitrate-citrate route was carried out. Optimisation of process parameters was done to resolve problems associated with large batch such as evolution of large amount of acidic fumes, increased gelation and drying time and incomplete calcination. The problem of exhaust of excess acidic fumes with size scale up was handled by passing ammonia and optimized pH of the sol. Process of drying the sol was optimised for large batch size. On scaling up from 6 g to 200 g batch incomplete crystallization was observed on calcination under conditions optimized for 6 g batch. The causes of incomplete calcination with size scale up was identified and resolved to achieve completely crystalline particles in the range of similar to 25 nm to 50 nm.