High Temperature Oxidation of Y&lt;SUB&gt;2&lt;/SUB&gt;O&lt;SUB&gt;3&lt;/SUB&gt; Partially-Stabilized ZrO&lt;SUB&gt;2&lt;/SUB&gt; Composites Dispersed with Ni Particles

Nanko, Makoto; Yoshimura, M.; Maruyama, Toru

doi:10.2320/matertrans.44.736

Cited by 17 publications

(7 citation statements)

References 20 publications

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“…However, in the case of SiC/Y 2 Si 2 O 7 composites, a lot of short cracks parallel to the sample surface are generated in the inside of the oxidized zone, as shown in Figure 7(b). Similar cracks were observed in Y 2 O 3 partially stabilized ZrO 2 composites dispersed with Ni particles after the oxidation process at high temperatures [15]. The cracks appeared in the inside of the oxidized zone of SiC/Y 2 Si 2 O 7 composites would be formed by oxidation of SiC dispersoid into SiO 2 which accompanies a volume expansion during high-temperature oxidation process.…”

Section: Discussionsupporting

confidence: 62%

Crack-healing performance and oxidation behavior of SiC dispersed yttrium silicate composites

Nanko

2020

Journal of Asian Ceramic Societies

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Yttrium silicate-based composites dispersed with silicon carbide particles have been proposed as a novel material concept of self-healing environmental barrier coatings applied for Si-based ceramics and their composites. Crack-healing effectiveness as well as high-temperature oxidation behavior of the yttrium silicate composites was investigated as functions of oxidation time and temperatures. Dense samples of the composites dispersed with 5 vol% SiC particles were fabricated by using the pulsed electric current sintering technique. Thermal oxidation for selfhealing was conducted at temperatures ranging from 1000°C to 1300°C for from 1 to 24 h in air. High-temperature oxidation experiments were carried out at temperatures ranging from 1200°C to 1400°C for from 1 to 60 h in air. As a result, the surface cracks with approximately 200 µm in length introduced on the sample surface were disappeared completely after heat treatment at 1300°C for 1 h in air. Crack-healing performance of SiC/Y 2 SiO 5 is better than that of SiC/Y 2 Si 2 O 7. The crack-healing performance of SiC/Y 2 SiO 5-Y 2 Si 2 O 7 is in the middle of that of SiC/Y 2 SiO 5 and SiC/Y 2 Si 2 O 7. The mechanism of crack healing was identified as the consequence of SiC oxidation into SiO 2 , which accompanies a volume expansion, and outward diffusion of Y 3+ cations caused the formation of Y 2 Si 2 O 7 outer layer. Oxidation of SiC particles within the matrix developed an oxidized zone. Growth of the oxidized zone obeyed the parabolic law, which meant diffusion process in the oxidized zone is the rate-controlling process.

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Section: Discussionsupporting

confidence: 62%

Crack-healing performance and oxidation behavior of SiC dispersed yttrium silicate composites

Nanko

2020

Journal of Asian Ceramic Societies

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“…Since this type of TBCs is usually porous, surrounding gas can pass into the inside of coating and oxidize the dispersed metallic particles. Nanko et al [15,16] studied high-temperature oxidation of dense Ni-dispersed partially stabilized zirconia (PSZ). Ni is a base-metal for heat-resistant alloys.…”

Section: Case Studiesmentioning

confidence: 99%

High-temperature oxidation of ceramic matrix composites dispersed with metallic particles

Nanko

2005

Science and Technology of Advanced Materials

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Oxidation behavior of ceramic matrix composites dispersed with metallic particles is discussed to establish materials design for hightemperature applications. Oxidation kinetics of ceramic matrix composites dispersed with metallic particles is understood from the viewpoint of the diffusion properties and defect chemistry of matrix oxides. High-temperature oxidation of Ni(p)/partially stabilized zirconia, Ni(p)/Al 2 O 3 and Ni(p)/MgO was described as examples. q

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“…Therefore, such part seems to have a low oxidation protection and tends to be oxidized selectively. These local rapid oxidations at the part that the bond coat protruded into the topcoat may generate local internal stresses near the bond coat/topcoat interface, and these can cause local fracture of the topcoat (Ref 10,15).…”

Section: Effects Of Chromate Treatment On Interfacial Oxidationmentioning

confidence: 99%

Oxidation Control with Chromate Pretreatment of MCrAlY Unmelted Particle and Bond Coat in Thermal Barrier Systems

et al. 2008

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MCrAlY alloy bond coat is widely used in thermal barrier coating (TBC) systems to protect substrates from high-temperature oxidizing environments. However, failure of the ceramic topcoat can occur due to a thermally grown oxide (TGO) that grows at the interface between the bond coat and the topcoat. In this study, the effect of chromate treatment was investigated. Prior to topcoat deposition, a thin film of Cr 2 O 3 was formed on the bond coat surface. High-temperature oxidation tests were carried out, and the oxidation rates were determined by inspection of cross sections. Similar oxidation tests were carried out using MCrAlY powder material assumed to be unmelted particles. As a result, the chromate-treated bond coat showed outstanding oxidation resistance. Calculations that take into account the oxidation of particles in the topcoat indicated the generation of internal stress to cause local fracture of the topcoat.

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High Temperature Oxidation of Y<SUB>2</SUB>O<SUB>3</SUB> Partially-Stabilized ZrO<SUB>2</SUB> Composites Dispersed with Ni Particles

Cited by 17 publications

References 20 publications

Crack-healing performance and oxidation behavior of SiC dispersed yttrium silicate composites

Crack-healing performance and oxidation behavior of SiC dispersed yttrium silicate composites

High-temperature oxidation of ceramic matrix composites dispersed with metallic particles

Oxidation Control with Chromate Pretreatment of MCrAlY Unmelted Particle and Bond Coat in Thermal Barrier Systems

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