Recent advances in spinel optical ceramic

Mroz, Thomas J.; Hartnett, T.; Wahl, J.; Goldman, Lee M.; Kirsch, James C.; Lindberg, William R.

doi:10.1117/12.607593

Cited by 29 publications

(33 citation statements)

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“…F ully dense polycrystalline alumina–magnesia spinel (referred to as spinel hereafter), MgAl 2 O 4 , is an attractive material for its excellent optical properties (in‐line transmittance) in the visible to mid‐infrared ranges 1,2 . It is currently considered as a cost‐effective alternative to monocrystalline sapphire for the manufacturing of infrared domes, which are to be mounted on the new generation of high‐speed air‐to‐air and ground‐to‐air missiles coming into the market.…”

Section: Introductionmentioning

confidence: 99%

Sintering Analysis of a Fine-Grained Alumina-Magnesia Spinel Powder

Benameur

Bernard‐Granger

Addad

et al. 2011

Journal of the American Ceramic Society

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Pressureless sintering in air of a fine‐grained alumina–magnesia spinel (MgAl2O4) powder has been investigated using anisothermal and isothermal methods. Grain growth is controlled by the grain boundaries and densification is controlled by volume diffusion or grain‐boundary diffusion (no possibility to do a distinction). The apparent activation energies measured for grain growth and densification are 1100±50 and 915±50 kJ/mol, respectively. Grain boundaries and triple points have a different composition than the core of spinel grains. This could be the reason for the exceptionally high values of activation energies measured for grain growth and densification.

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Section: Introductionmentioning

confidence: 99%

Sintering Analysis of a Fine-Grained Alumina-Magnesia Spinel Powder

Benameur

Bernard‐Granger

Addad

et al. 2011

Journal of the American Ceramic Society

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“…Progress toward the development of transparent magnesium aluminate spinel (MgAl 2 O 4 ) has been steady over many years and is nearing technical fruition for military applications in protection and optical systems . Recent development effort has focused on improving the manufacturing reliability at ever increasing scales or on the improvement of material strength and durability.…”

Section: Introductionmentioning

confidence: 99%

Transparent Solid Solution Magnesium Aluminate Spinel Polycrystalline Ceramic with the Alumina‐Rich Composition MgO·1.2 Al₂O₃

et al. 2011

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Solid solution magnesium aluminate spinel with the alumina‐rich composition MgO·1.2 Al2O3 has been prepared as a transparent polycrystalline ceramic with average in‐line transmission at 550 nm of 84.8 ± 2.7% and >82% throughout the visible spectrum. Starting powders are prepared from mixtures of high purity Mg(OH)2 and γ‐Al2O3 thoroughly mixed in an aqueous slurry. Water is removed by rotary evaporation. The solids are collected, dried, calcined, mixed with LiF (as a sintering aid), and sieved. The powders are sintered into dense ceramics by hot pressing at 1600°C under vacuum and 20 MPa uniaxial load followed by hot isostatic pressing at 1850°C under 200 MPa Ar. Final grain sizes ranged between 300 and 1000 μm. Samples exhibited flexural strength of 176.8 ± 46.2 MPa; hardness of 12.3 ± 0.2 GPa; and elastic modulus of 292.9 ± 7.5 GPa. Control samples of stoichiometric magnesium aluminate spinel (MgO·Al2O3) were prepared with the same procedure and exhibited comparable values for transmission and physical properties.

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“…Magnesium aluminate spinel (MgAl 2 O 4 ) has been studied periodically since the 1960s; 7–13 however, most of its study has been aimed at infrared (IR) radome and transparent armor applications. MgAl 2 O 4 has great potential as a transparent scintillator material due to its good optical and nonhygroscopic properties 7 .…”

Section: Introductionmentioning

confidence: 99%

Characterizations of a Hot‐Pressed Polycrystalline Spinel:Ce Scintillator

Chen

Doty

Houk

et al. 2010

Journal of the American Ceramic Society

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Here, we report a new polycrystalline ceramic scintillator for possible use in γ‐ray detection and medical imaging applications. The goal was to develop a cerium‐doped spinel (MgAl2O4:Ce), which can be processed utilizing ceramic forming techniques. High‐purity MgAl2O4 powders were used as the starting materials. Lithium fluoride (LiF) was used as a sintering aid and CeO2 powder was used as the dopant. The mixed and dried powders were hot pressed in a vacuum environment to achieve high‐density MgAl2O4:Ce. The hot‐pressed sample shows a transparent polycrystalline appearance. In‐line transmission was measured to determine the transparency of the structure. Microstructures were characterized using X‐ray diffraction and scanning electron microscopy. Fluorescence absorption and emission peaks were also measured in addition to the decay time measurement.

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Recent advances in spinel optical ceramic

Cited by 29 publications

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Sintering Analysis of a Fine-Grained Alumina-Magnesia Spinel Powder

Sintering Analysis of a Fine-Grained Alumina-Magnesia Spinel Powder

Transparent Solid Solution Magnesium Aluminate Spinel Polycrystalline Ceramic with the Alumina‐Rich Composition MgO·1.2 Al₂O₃

Characterizations of a Hot‐Pressed Polycrystalline Spinel:Ce Scintillator

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Recent advances in spinel optical ceramic

Cited by 29 publications

References 0 publications

Sintering Analysis of a Fine-Grained Alumina-Magnesia Spinel Powder

Sintering Analysis of a Fine-Grained Alumina-Magnesia Spinel Powder

Transparent Solid Solution Magnesium Aluminate Spinel Polycrystalline Ceramic with the Alumina‐Rich Composition MgO·1.2 Al2O3

Characterizations of a Hot‐Pressed Polycrystalline Spinel:Ce Scintillator

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Transparent Solid Solution Magnesium Aluminate Spinel Polycrystalline Ceramic with the Alumina‐Rich Composition MgO·1.2 Al₂O₃