Abstract
The effects of lithium doping on the sintering and grain growth of non-stoichiometric nano-sized magnesium aluminate spinel were studied using a spark plasma sintering (SPS) apparatus. Li-doped nano-MgO· nAl2O3 spinel (n = 1.06 and 1.21) powders containing 0, 0.20, 0.50 or 1.00 at. % Li were synthesized by the solution combustion method and dense specimens were processed using a SPS apparatus at 1200 °C and under an applied pressure of 150 MPa. The SPS-processed samples showed mutual dependency on the lithium concentration and the alumina-to-magnesia ratio. For example, the density and hardness values of near-stoichiometry samples (n = 1.06) showed an incline up to 0.51 at. % Li, while in the alumina rich samples (n = 1.21), these values remained constant up to 0.53 at. % Li. Studying grain growth revealed that in the Li-MgO· nAl2O3 system, grain growth is limited by Zener pining. The activation energies of undoped, 0.2 and 0.53 at. % Li-MgO· 1.21Al2O3 samples were 288 ± 40, 670 ± 45 and 543 ± 40 kJ· mol-1, respectively.
Original language | American English |
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Article number | 481 |
Journal | Materials |
Volume | 9 |
Issue number | 6 |
DOIs | |
State | Published - 16 Jun 2016 |
Keywords
- Grain growth
- Lithium
- Magnesium aluminate spinel
- Precipitation
- SPS
All Science Journal Classification (ASJC) codes
- General Materials Science