Effect of Heat Treatment on Plasma-Sprayed Zircon (ZrSiO ZrSiO<sub>4</sub>)

Suzuki, Masato; Inoue, Satoshi; Ueno, K.

doi:10.1080/10426919808935277

Cited by 7 publications

(4 citation statements)

References 4 publications

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“…The roof with an 80‐μm MSZ coating can significantly reduce the under‐roof temperature by 13.8°C, much lower than 5.2°C achieved by the n‐zircon‐based roof. The decent thermal shielding stems from the low thermal conductivities of the MSZ powders ranging 0.20‐0.47 W m –1 K –1 from 23°C to 500°C (Table ), which are superior to n‐zircon (0.40‐2.58 W m –1 K –1 ) and bulk/film zircons (3.5‐5.1 or 5‐14 W m –1 K –1 ) 6,56 . The advantage evolves primarily from the unique structure of zircon spheres comprising of a large quantity of closely interconnected sublayers, which isolate abundant micropores and mesopores that can extraordinarily reduce the mean free path of phonon to decrease the thermal conductivity 6 …”

Section: Resultsmentioning

confidence: 99%

Effect of halide mineralizers on monodisperse spherical zircon powders

et al. 2021

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Zircon has been widely applied in various traditional and emerging fields due to its distinct physiochemical advantages while monodisperse spherical zircon (MSZ) powders hitherto have not been explored for the tremendous challenges in the control of zircon crystallization and growth. Herein, systematic investigations are presented to reveal the paramount role of halide mineralizers upon the crystallization and growth of MSZ powders synthesized under highly acidic hydrothermal environments (pH <0). A formation mechanism is revealed revolving around the complexation of central Zr4+ with the Lewis basic ligand, fluorine, which forms the F‐containing species of [(OH)1–y·Ry] (R = F, Cl) to replace Zr and generates Zr‐deficient zircons as (ZrO4)1‐xSi[(OH)1‐y·Ry]4x. This finding differs much from conventional views on common fluoro‐hydroxylated hydrothermal zircons, which were generally regarded as Si‐deficient silicates from the substitution of fluoro‐hydroxyls for the [SiO4] tetrahedra. A parameter, Kr=4xy, is first proposed as an index to evaluate the stability of hydrothermal zircons. The MSZ powders demonstrate superb thermal stability at high temperature, superior photo‐reflectance, and thermal insulation over normal zircons, promising attractive prospects to extend zircon applications.

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Section: Resultsmentioning

confidence: 99%

Effect of halide mineralizers on monodisperse spherical zircon powders

et al. 2021

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“…This non-linear expansion behavior was also observed in the APS coating which was sprayed at lower substrate temperature. 6,7) The H18 coating (T s ¼ 1223 K) showed linear thermal expansion behavior up to 1200 K, and a huge shrinkage occurs at higher temperature. The H12 coating, with higher substrate temperature (T s ¼ 1473 K), showed almost linear thermal expansion up to 1500 K, and no shrinkage at higher temperature.…”

Section: Thermal Expansionmentioning

confidence: 99%

“…The authors had reported on the structure of the zircon coating prepared by a conventional atmospheric plasma spray (APS) process. 6,7) It was revealed that open porosity of the as-sprayed coating was 10% with a lot of cracks, however it decreased after the heat treatment at 1473 K because of the phase transformation of zirconia from tetragonal to monoclinic with a volume expansion. Then porosity increased up to 10% after the heat treatment at 1673 K, because of the huge volume shrinkage during the formation of zircon at 1673 K. Thus, the APS zircon coating showed an inferior stability at elevated temperatures.…”

Section: Introductionmentioning

confidence: 99%

Structure Control of Plasma Sprayed Zircon Coating by Substrate Preheating and Post Heat Treatment

2005

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Zircon is widely used in industrial field as a refractory material, because of its excellent mechanical and chemical properties at high temperature. Authors have been studied on the effect of the heat treatment on the structure and properties of plasma sprayed zircon coating as a candidate for an environmental barrier coating (EBC). In this study, very dense coating with excellent adhesive strength was successfully obtained by optimizing the spray process. Substrate temperature is one of the dominant factors to control porosity and crack formation in the coating. The higher substrate temperature, obtained by plasma pre-heating, resulted in lower porosity and less cracks. Open porosity of the coating was quite low, about 2%, in the coatings obtained especially above 1473 K of the substrate temperature.

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“…The nominal chemical composition of zircon is 67.1 wt % ZrO 2 and 32.9 wt % SiO 2 , but there are also small amounts of Fe 2 O 3 , cerium, thorium, or hafnium [1]. Zircon is among the most widely used and cheapest spray-coating material for refractory applications [5][6][7][8][9]. Zircon decomposes into zirconia (ZrO 2 ) and silica (SiO 2 ) during plasma spraying, and does not recombine if cooled quickly enough [9][10][11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Zircon-Based Ceramic Coatings Formed by a New Multi-Chamber Gas-Dynamic Accelerator

et al. 2017

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Abstract:In this work, dense zircon-based ceramic coatings were obtained from inexpensive zircon powder on a steel substrate by using a new multi-chamber gas-dynamic accelerator. The microstructure and phase composition of the coating were characterized by scanning electron microscopy, optical microscopy, and X-ray diffraction. The mechanical properties of the coatings were evaluated using microindentation, wear tests and bonding strength tests. The results showed that the obtained zircon-based ceramic coatings were continuous without cracks and bonded well with substrate without a sublayer. The zircon-based ceramic coatings consisted of c-ZrO 2 (major phase), m-ZrO 2 and SiO 2 . The zircon-based ceramic coatings had a porosity of 0.1%, hardness of 526 ± 65 HV 0.2 , and a fracture toughness of 2.5 ± 0.6 (MPa·m 1/2 ). The coatings showed the low specific wear rate and average erosion rate. The failure mode occurring in the tested coatings was cohesive.

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Effect of Heat Treatment on Plasma-Sprayed Zircon (ZrSiO ZrSiO₄)

Cited by 7 publications

References 4 publications

Effect of halide mineralizers on monodisperse spherical zircon powders

Effect of halide mineralizers on monodisperse spherical zircon powders

Structure Control of Plasma Sprayed Zircon Coating by Substrate Preheating and Post Heat Treatment

Zircon-Based Ceramic Coatings Formed by a New Multi-Chamber Gas-Dynamic Accelerator

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Effect of Heat Treatment on Plasma-Sprayed Zircon (ZrSiO ZrSiO4)

Cited by 7 publications

References 4 publications

Effect of halide mineralizers on monodisperse spherical zircon powders

Effect of halide mineralizers on monodisperse spherical zircon powders

Structure Control of Plasma Sprayed Zircon Coating by Substrate Preheating and Post Heat Treatment

Zircon-Based Ceramic Coatings Formed by a New Multi-Chamber Gas-Dynamic Accelerator

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Product

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Effect of Heat Treatment on Plasma-Sprayed Zircon (ZrSiO ZrSiO₄)