Influence of pH values on (Nd + Y):Al molar ratio of Nd:YAG nanopowders and preparation of transparent ceramics

The Nd:YAG ceramics were fabricated by vacuum sintering at 1750 °C for 20 h, where the raw nanopowders were synthesized by the co-precipitation method, and calcined at 1050 °C for 2 h. The effect of the pH values of reaction solution on the (Nd + Y):Al mole ratio of the powders was discussed here. It was found that the pH value range of 7.9-8.2 was suitable for the preparation of the Nd:YAG nanopowders. Secondary phases and pores appeared in and between the grains of Nd:YAG ceramic with the (Nd + Y):Al mole ratio of 0.576. The specimens with the (Nd + Y):Al mole ratio range of 0.598-0.603 had fine microstructures, and their transmissions were both over 80% at the near infrared wavelength. If the (Nd + Y):Al mole ratio reached 0.648, many secondary phases occurred along the grain boundaries.