Pulsed electric current sintering of transparent Cr-doped Al2O3

Dang, Khanh Quoc; Takei, Satoshi; Kawahara, Masakazu; Nanko, Makoto

doi:10.1016/j.ceramint.2010.11.009

Cited by 17 publications

(7 citation statements)

References 42 publications

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“…At high chromium concentration, the color of the compounds is green [ 4 ]. The advantages of ruby are high heat resistance, high melting point, high mechanical strength, high transparency, and excellent chemical stability [ 13 ]. More importantly, the compounds can exhibit a remarkable reversible thermochromic phenomenon [ 12 ].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Thermochromic Properties of Cr-Doped Al2O3 for a Reversible Thermochromic Sensor

2017

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An inorganic thermochromic material based on Cr-doped Al2O3 is synthesized using a solid-state method. The crystal structure, chemical composition, and morphology of the synthesized material are analyzed using X-ray diffraction, scanning electron microscopy coupled with an energy-dispersive X-ray spectrometer, and Fourier transform infrared (FT-IR) spectroscopy. The color performances of the synthesized material are analyzed using a UV-VIS spectrometer. Finally, the thermochromism exhibited by the powdered samples at high temperatures is investigated. The material exhibits exceptional thermochromic property, transitioning from pink to gray or green in a temperature range of 25–600 °C. The change in color is reversible and is dependent on the surrounding temperature and chromium concentration; however, it is independent of the exposure time. This novel property of Cr-doped Al2O3 can be potentially employed in reversible thermochromic sensors that could be used not only for warning users of damage due to overheating when the environmental temperature exceeds certain limits, but also for detecting and monitoring the temperature of various devices, such as aeronautical engine components, hotplates, and furnaces.

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Section: Introductionmentioning

confidence: 99%

Synthesis and Thermochromic Properties of Cr-Doped Al2O3 for a Reversible Thermochromic Sensor

2017

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“…This suggests that PCA could be a potential host material for phosphor and laser applications. Until now, the transparent ruby ceramics have been fabricated by vacuum sintering, 38 HIP, 48 and SPS technique 45,54,65,66 . For representative 0.5 at.% Cr ruby ceramics (0.8 mm thickness), Wang et al 65 ,.…”

Section: Photoluminescence In Rare Earth/transition Metal‐doped Trans...mentioning

confidence: 99%

“…Until now, the transparent ruby ceramics have been fabricated by vacuum sintering, 38 HIP, 48 and SPS technique. 45,54,65,66 For representative 0.5 at.% Cr ruby ceramics (0.8 mm thickness), Wang et al 65 , Drdlikova et al 48 , and Penilla et al 54 reported in-line transmittance of ∼39%, ∼49%, and ∼58% at 700 nm, respectively. The highest value of transmittance ∼72.5% at 700 nm was reached by Ratzker et al 45 for ruby ceramic sample, with an average grain size of ∼180 nm, sintered by an SPS technique at a high pressure of 600 MPa.…”

Section: Al 2 O 3 :Tmmentioning

confidence: 99%

Photoluminescence of rare‐earth/transition metal‐doped transparent/translucent polycrystalline Al₂O₃ ceramics: A review

et al. 2022

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Transparent alumina doped with rare‐earth or transition metal oxides represents a group of materials suitable for optical applications. Because of the birefringence of alumina, their preparation is demanding on the quality of starting materials, their advanced shaping, and pressure‐assisted sintering. Spark plasma sintering and hot isostatic pressing have proven at achieving pore‐free fine microstructures exhibiting high in‐line transmission and a sufficient intensity of emitted light. The present review aims to summarize the results published on this topic, to compare them and on this base to propose other possible and/or appropriate approaches to future.

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“…Transparent polycrystalline Al 2 O 3 ceramics have a high potential to replace the single crystal sapphire in many industrial applications. Besides its good mechanical properties as well as good optical transparency, the main advantage of polycrystalline Al 2 O 3 is the simpler production method along with the lower cost by various sintering techniques such as pulsed electric current sintering (PECS) or hot isostatic pressing (HIP) [1][2][3][4][5]. Moreover, with the sintering techniques, the polycrystalline Al 2 O 3 samples can be shaped much more easily while the single crystal sapphire normally requires machining for shaping after the production of a large bulk.…”

Section: Introductionmentioning

confidence: 99%

Influences of TiO₂ or Y₂O₃ doping on the homogeneity of polycrystalline Al₂O₃ produced by pulsed electric current sintering

Nguyen

Shirai

Xin

et al. 2021

Journal of Asian Ceramic Societies

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Influences of TiO 2 or Y 2 O 3 dopants on pressure-assisted sintering of polycrystalline Al 2 O 3 were investigated to control the microstructure of sintered Al 2 O 3 as well as to improve the homogeneity of transparent Al 2 O 3 samples. The transparent polycrystalline Al 2 O 3 samples with and without the dopants were fabricated by two-step pulsed electric current sintering (TS-PECS). By the grain boundary segregation by the dopants, both TiO 2 and Y 2 O 3 depressed the densification and grain growth processes during the sintering of polycrystalline Al 2 O 3 . The principle originalities of this work include the relationship between the homogeneities of microstructure and of optical transmittance of large-size polycrystalline Al 2 O 3 and the consequent doping strategy for controlling of homogeneity of transparent polycrystalline Al 2 O 3 prepared by twostep PECS. Doping of Y 2 O 3 dramatically reduced the grain size of polycrystalline Al 2 O 3 and improved its optical transparency. The homogeneity of the microstructure and the optical transparency of the large-sized polycrystalline Al 2 O 3 with 0.1 mol% Y 2 O 3 was improved. The addition of TiO 2 also slightly retarded densification and reduced the grain size of the sintered Al 2 O 3 samples. However, TiO 2 dopant is not good for applications of transparent Al 2 O 3 because it caused a dark color in transparent polycrystalline Al 2 O 3 samples by uncertain reasons.

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Pulsed electric current sintering of transparent Cr-doped Al2O3

Cited by 17 publications

References 42 publications

Synthesis and Thermochromic Properties of Cr-Doped Al2O3 for a Reversible Thermochromic Sensor

Synthesis and Thermochromic Properties of Cr-Doped Al2O3 for a Reversible Thermochromic Sensor

Photoluminescence of rare‐earth/transition metal‐doped transparent/translucent polycrystalline Al₂O₃ ceramics: A review

Influences of TiO₂ or Y₂O₃ doping on the homogeneity of polycrystalline Al₂O₃ produced by pulsed electric current sintering

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Pulsed electric current sintering of transparent Cr-doped Al2O3

Cited by 17 publications

References 42 publications

Synthesis and Thermochromic Properties of Cr-Doped Al2O3 for a Reversible Thermochromic Sensor

Synthesis and Thermochromic Properties of Cr-Doped Al2O3 for a Reversible Thermochromic Sensor

Photoluminescence of rare‐earth/transition metal‐doped transparent/translucent polycrystalline Al2O3 ceramics: A review

Influences of TiO2 or Y2O3 doping on the homogeneity of polycrystalline Al2O3 produced by pulsed electric current sintering

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Photoluminescence of rare‐earth/transition metal‐doped transparent/translucent polycrystalline Al₂O₃ ceramics: A review

Influences of TiO₂ or Y₂O₃ doping on the homogeneity of polycrystalline Al₂O₃ produced by pulsed electric current sintering