Effect of Batch-to-Batch Variability on the Phase Transition of Precipitated Erbium-Doped Alumina Particles

Report No. ARL-TR-8202
Authors: Nicholas Ku; Victoria L Blair; Raymond E Brennan
Date/Pages: November 2017; 24 pages
Abstract: Alumina (Al2O3, aluminum oxide) is an excellent candidate as an optical material for laser gain media due to its high thermal conductivity. However, a rare earth (RE) cation dopant is necessary for the material to lase. To combat the dopant issue, nanosized alumina particles were synthesized via co-precipitation to trap RE ions in the alumina lattice before calcination. The wet co-precipitation process allowed for high purity and homogeneous distribution of the RE ions within the particles. A common issue with laboratory-scale synthesis is batch-to-batch variability. The reproducibility of the precipitated powder was investigated by holding the synthesis conditions constant. Variability of the phase transition temperature of alumina powder was tracked between batches, and showed a less than 1% difference in the transition temperature for gamma(γ)-alumina, as determined by high-temperature differential scanning calorimetry (HT-DSC).
Distribution: Approved for public release
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Last Update / Reviewed: November 1, 2017