The effects of heat treatment on the phase transformation behavior of plasma-sprayed stabilized ZrO2 coatings

Moon, Jaeyun; Choi, Hanshin; Kim, Hyungjun; Lee, Changhee

doi:10.1016/s0257-8972(01)01661-9

Cited by 114 publications

(42 citation statements)

References 8 publications

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“…Upon high-temperature exposure, yttria diffuses out of the t 0 -ZrO 2 phase until it reaches its equilibrium concentration over increased aging temperature or prolonged aging times, which results in the decomposition of t 0 -ZrO 2 phase into two high-temperature equilibrium phases: t-ZrO 2 phase and c-ZrO 2 phase. During the subsequent process of Journal of Thermal Spray Technology cooling to room temperature, the t-ZrO 2 phase may transform into m-ZrO 2 phase (Ref [18][19][20], and the c-ZrO 2 phase may transform into another metastable yttrium-rich tetragonal (t 00 -ZrO 2 ) phase or it may be retained ( Ref 14,21). In evidence, seven distinct peaks were detected on the ASPS coatings in the range of 72°< 2h < 76° (Fig.…”

Section: Phase Stabilitymentioning

confidence: 99%

Thermal Aging Behavior of Axial Suspension Plasma-Sprayed Yttria-Stabilized Zirconia (YSZ) Thermal Barrier Coatings

et al. 2014

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7.5YSZ thermal barrier coatings (TBCs) were deposited onto the stainless steel substrates using axial suspension plasma spraying (ASPS). Free-standing coatings were isothermally aged in air from 1200 to 1600°C for 24 h and at 1550°C for 20 to 100 h, respectively. Thermal aging behavior such as phase composition, microstructure evolutions, grain growth, and mechanical properties for thermal-aged coatings were investigated. Results show that the as-sprayed metastable tetragonal (t 0 -ZrO 2 ) phase decomposes into equilibrium tetragonal (t-ZrO 2 ) and cubic (c-ZrO 2 ) phases during high-temperature exposures. Upon further cooling, the c-ZrO 2 may be retained or transform into another metastable tetragonal (t 00 -ZrO 2 ) phase, and tetragonal fi monoclinic phase transformation occurred after 1550°C/ 40 h aging treatment. The coating exhibits a unique structure with segmentation cracks and micro/nanosize grains, and the grains grow gradually with increasing aging temperature and time. In addition, the hardness (H) and YoungÕs modulus (E) significantly increased as a function of temperature due to healing of pores or cracks and grain growth of the coating. And a nonmonotonic variation is found in the coatings thermal aged at a constant temperature (1550°C) with prolonged time, this is a synergetic effect of coating sintering and m-ZrO 2 phase formation.

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Section: Phase Stabilitymentioning

confidence: 99%

Thermal Aging Behavior of Axial Suspension Plasma-Sprayed Yttria-Stabilized Zirconia (YSZ) Thermal Barrier Coatings

et al. 2014

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“…It is generally known that pure zirconia exists in three crystallographic phases: low-temperature monoclinic phase (m-ZrO 2 , space group P2 1 /c), intermediate-temperature tetragonal phase (t-ZrO 2 , space group P4 2 /nmc) and high-temperature cubic phase (c-ZrO 2 , space group Fm3m). However, the transformation from tetragonal to monoclinic phase (t→m) is accompanied by 3-5% volume expansion, which limits the usage of ZrO 2 ceramics as structural materials [10]. Therefore, the desire to stabilize high temperature (cubic and tetragonal) phases at room temperature has led to a variety of oxide additions to lower even suppress the martensitic transition.…”

Section: Introductionmentioning

confidence: 99%

Effect of Y2O3 addition on the phase composition and crystal growth behavior of YSZ nanocrystals prepared via coprecipitation process

Zhou

Yuan

Huang

et al. 2015

Ceramics International

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“…Yttria-stabilized zirconia with a composition of 3.5-4.5 mol%Y 2 O 3 -ZrO 2 , here abbreviated as YSZ, ceramic deposits is often applied as top coat material for TBCs (Ref 1) YSZ coating canÕt be used for long-term above 1200°C due to the destructive phase transformation of tetragonal phase to monoclinic phase which results in a significant change in volume of the coating and can cause cracking and rapid degradation of a TBC, especially under thermal cycling conditions Ref (2)(3)(4). In order to increase usage temperature of TBCs, it is very important that the TBCs structure should be designed to be ''phase nontransformable'' ( Ref 5).…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Phase Stability of Scandia, Gadolinia, and Ytterbia Co-doped Zirconia for Thermal Barrier Coating Application

Cui

Liu

et al. 2014

J Therm Spray Tech

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Scandia, gadolinia, and ytterbia co-doped zirconia (SGYZ) ceramic powder was synthesized by chemical co-precipitation and calcination processes for application in thermal barrier coatings to promote the durability of gas turbines. The ceramic powder was agglomerated and sintered at 1150°C for 2 h, and the powder exhibited good flowability and apparent density to be suitable for plasma spraying process. The microstructure, morphology and phase stability of the powder and plasma-sprayed SGYZ coatings were analyzed by means of scanning electron microscope and x-ray diffraction. Thermal conductivity of plasma-sprayed SGYZ coatings was measured. The results indicated that the SGYZ ceramic powder and the coating exhibit excellent stability to retain single non-transformable tetragonal zirconia even after high temperature (1400°C) exposure for 500 h and do not undergo a tetragonal-to-monoclinic phase transition upon cooling. Furthermore, the plasma-sprayed SGYZ coating also exhibits lower thermal conductivity than yttria stabilized zirconia coating currently used in gas turbine engine industry. SGYZ can be explored as a candidate material of ultra-high temperature thermal barrier coating for advanced gas turbine engines.

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The effects of heat treatment on the phase transformation behavior of plasma-sprayed stabilized ZrO2 coatings

Cited by 114 publications

References 8 publications

Thermal Aging Behavior of Axial Suspension Plasma-Sprayed Yttria-Stabilized Zirconia (YSZ) Thermal Barrier Coatings

Thermal Aging Behavior of Axial Suspension Plasma-Sprayed Yttria-Stabilized Zirconia (YSZ) Thermal Barrier Coatings

Effect of Y2O3 addition on the phase composition and crystal growth behavior of YSZ nanocrystals prepared via coprecipitation process

Synthesis and Phase Stability of Scandia, Gadolinia, and Ytterbia Co-doped Zirconia for Thermal Barrier Coating Application

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