Improvement of optical properties of Nd:YAG transparent ceramics by post-annealing and post hot isostatic pressing

The Nd:YAG transparent ceramics were fabricated by vacuum sintering. The Nd:YAG samples were annealed at 1450 degrees C for 20 h in air and followed by hot isostatic pressing (HIP) at 1700 degrees C for 2 h in 200 MPa Ar and then re-annealed at 1250-1450 degrees C for 10 h in air. The experimental results showed that the optical properties of Nd:YAG samples varied markedly with different post treatments. After air annealing at 1450 degrees C for 20 h and HIP at 1700 degrees C for 2 h under 200 MPa of Ar and then air re-annealing at 1250 C for 10 h, the transmittances of the samples increased from 51.2% to 77.2% (at 400 nm) and 78.4% to 83.6% (at 1064 nm), respectively. The annealing and HIP are effective post treatments to reduce oxygen vacancies and intergranular pores respectively in Nd:YAG transparent ceramics. (C) 2013 Elsevier B.V. All rights reserved.