Infrared transmittance of hybrid microwave sintered yttria

Mathew, C.T.; Solomon, Sam; Koshy, J.; Thomas, J.K.

doi:10.1016/j.ceramint.2015.04.100

Cited by 12 publications

(17 citation statements)

References 41 publications

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“…The pellet sintered at 1600 ℃ for a soaking duration of 2 h achieves a density equal to 98.8% of the theoretical density. This sintering temperature is 20 ℃ lower than that required for pure yttria reported in our previous work [32]. This high densification without any sintering additives is attributed to the powder quality of the sample produced by modified combustion technique.…”

Section: Resultsmentioning

confidence: 51%

“…The upper infrared cut off or the long wavelength edge of transparent ceramics is [34]. Compared to pure yttria sintered via hybrid heating, LY3 H is having a slight increase in the transmittance and infrared cut off [32]. The size of La 3+ ion is greater than that of Y 3+ ion.…”

Section: Resultsmentioning

confidence: 99%

“…The sample LY3 from the group shows enhanced transmittance, infrared cut off, and hardness compared to the pure yttria, and the thermal conductivity is within the range of ideal windows [32]. Further analysis reveals that the samples with higher concentration show very low thermal conductivity which falls below the ideal range and are not desirable for a high quality transparent window which is used for strategic defence and space mission [19].…”

Section: Resultsmentioning

confidence: 99%

“…A remarkable reduction in sintering temperature and soaking duration is shown by pellets sintered via hybrid heating. The sintering strategy optimised by us after several trials is utilised in this work as well [32]. That is the resistive heating and microwave heating are effectively coupled in the ratio of 60:40 below 1100 ℃ and thereafter it is fixed at 40:60.…”

Section: Resultsmentioning

confidence: 99%

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Influence of La3+ ion in the yttria matrix in improving the microhardness of infrared transparent nano LaxY2-xO3 sintered via hybrid heating

et al. 2017

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Abstract:In the present work, hybrid sintering technique which couples the resistive heating and microwave heating is employed to sinter infrared transparent La 0.15 Y 1.85 O 3 to 99.2% of the theoretical density for the first time to the best of our knowledge. The presence of La 3+ in the yttria matrix improves the hardness properties to a greater extent without affecting the transmittance properties, but there is a deterioration in the thermal properties of the sample. So we have limited our studies to La 0.15 Y 1.85 O 3 which shows better optical, thermal, and hardness properties. The pellets fabricated from the ultra-fine nano powder with average particle size of ~12 nm synthesized by combustion technique and sintered at 1430 ℃ with an average grain size of 0.22 µm show ~80.1% transmittance in the UV-visible region and 81% in mid infrared region. For a comparative study of the optical, mechanical, and thermal properties, two other variants of sintering strategies namely conventional sintering and microwave sintering are also employed. A comprehensive analysis on the hardness reveals that the hardness of the pellets sintered via hybrid heating is 9.73 GPa and is superior to the pellets sintered using the other two techniques. The thermal conductivity of the sample is also analyzed in detail. The results clearly indicate that the La 0.15 Y 1.85 O 3 ultra-fine nano powder synthesised by the single-step combustion method and sintered via microwave hybrid heating shows better transmittance properties without compromising the mechanical properties, and can be used very effectively for the fabrication of infrared transparent windows and domes.

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Section: Resultsmentioning

confidence: 51%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Influence of La3+ ion in the yttria matrix in improving the microhardness of infrared transparent nano LaxY2-xO3 sintered via hybrid heating

et al. 2017

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“…It involves no complex steps and is economical in terms of time, energy and cost. Very recently, we have synthesized and sintered Y 2 O 3 and MgAl 2 O 4 nanopowders using the integrated resistive–microwave heating using hybrid microwave heating with improved characteristics …”

Section: Introductionmentioning

confidence: 99%

Hybrid Microwave Sintering of Infrared Transparent Nano‐Y₃Al₅O₁₂ Synthesized by a Modified Combustion Technique

Christopher

Solomon

Koshy

et al. 2016

Int J Applied Ceramic Tech

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Infrared transparent ceramics found to have numerous civilian and defense applications. In the present work, Y3Al5O12 nanoparticles were synthesized by an auto‐igniting modified single‐step combustion method. The structure and morphology of the as‐prepared powder revealed the phase purity and ultrafine nature of the powder having an average crystallite size of 16 nm and well‐defined lattice planes. Coupling of the resistive and microwave heating at precise proportion leads to a sintered density of the powder with 99.3% of the theoretical density at a temperature as low as 1470°C for a soaking duration of just 20 min. Marked reduction in grain size and the porosity was also observed for the hybrid sintered pellets. An average grain size of 167 nm was measured for the sintered pellets, which also showed a high transmittance of 80% in the UV–vis region and 82.5% in the mid‐IR region.

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Enhanced infrared transmission characteristics of microwave-sintered $$\hbox {Y}_{2}\hbox {O}_{3}$$ Y 2 O 3 – $$\hbox {MgO}$$ MgO nanocomposite

et al. 2017

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Infrared (IR) transparent ceramics are found to have applications in demanding defence and space missions. In this work, Y 2 O 3-MgO nanocomposites were synthesised by a modified single-step combustion technique. The characterisation of the as-prepared powder by X-ray diffraction and transmission electron microscopy revealed the presence of cubic phases of ultra-fine nanostructured Y 2 O 3 and MgO, with an average crystallite size of ∼19 nm. For the first time the resistive and microwave heatings were effectively coupled for sintering the sample, and it was found that the sintering temperature and soaking time were reduced considerably. The pellets were sintered to 99.2% of the theoretical density at 1430 • C for a soaking duration of 20 min. The well-sintered pellets with an average grain size of ∼200 nm showed better transmittance properties relative to pure yttria. The promising percentage transmission of 80% in the UV-visible region and 82% in the mid-IR region shown by Y 2 O 3-MgO nanocomposites can be tailored and made cost-effective to fabricate high-quality IR windows for strategic defence and space missions.

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Infrared transmittance of hybrid microwave sintered yttria

Cited by 12 publications

References 41 publications

Influence of La3+ ion in the yttria matrix in improving the microhardness of infrared transparent nano LaxY2-xO3 sintered via hybrid heating

Influence of La3+ ion in the yttria matrix in improving the microhardness of infrared transparent nano LaxY2-xO3 sintered via hybrid heating

Hybrid Microwave Sintering of Infrared Transparent Nano‐Y₃Al₅O₁₂ Synthesized by a Modified Combustion Technique

Enhanced infrared transmission characteristics of microwave-sintered $$\hbox {Y}_{2}\hbox {O}_{3}$$ Y 2 O 3 – $$\hbox {MgO}$$ MgO nanocomposite

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Infrared transmittance of hybrid microwave sintered yttria

Cited by 12 publications

References 41 publications

Influence of La3+ ion in the yttria matrix in improving the microhardness of infrared transparent nano LaxY2-xO3 sintered via hybrid heating

Influence of La3+ ion in the yttria matrix in improving the microhardness of infrared transparent nano LaxY2-xO3 sintered via hybrid heating

Hybrid Microwave Sintering of Infrared Transparent Nano‐Y3Al5O12 Synthesized by a Modified Combustion Technique

Enhanced infrared transmission characteristics of microwave-sintered $$\hbox {Y}_{2}\hbox {O}_{3}$$ Y 2 O 3 – $$\hbox {MgO}$$ MgO nanocomposite

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Hybrid Microwave Sintering of Infrared Transparent Nano‐Y₃Al₅O₁₂ Synthesized by a Modified Combustion Technique