Microstructure and thermal & mechanical properties of La2Zr2O7@YSZ composite ceramic
Source abstract
Abstract
Abstract La2Zr2O7 used as a top coat material has low thermal conductivity and high stability at high temperature, but it also has a low fracture toughness, which limits its application. To improve the fracture toughness of La2Zr2O7, a La2Zr2O7@YSZ core–shell structured composite ceramic was designed and prepared. The morphology of the La2Zr2O7@YSZ composite ceramic was investigated using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The resulting images show that the YSZ is coated on the surface of the La2Zr2O7. The phases were analyzed by X-ray diffraction (XRD), and the XRD patterns show that pyrochlore and fluorite structures coexist in the La2Zr2O7@YSZ composite material without any chemical reaction. Differential scanning calorimetry (DSC) was used to detect the heat change of the composite ceramic during heat treatment. The properties of the La2Zr2O7@YSZ composite ceramic, such as the thermal conductivity, coefficient of thermal expansion (CTE), and mechanical properties were investigated using a laser flash method, high-temperature dilatometer, and nano-hardness tests, respectively. The thermal conductivity of the composite ceramic is in the range of 1.7745–2.3076 W m−1 K−1 in the temperature regime of 200–1000 °C. The maximum CTE of the composite ceramic is 10.3 × 10−6/°C. Owing to the thin YSZ coating on the La2Zr2O7 surface, the hardness and Young's modulus of the composite ceramic are 8.17 GPa and 168.3 GPa, respectively. The nucleation and propagation of micro-cracks are investigated using a micro-hardness tester. Compared to La2Zr2O7, the micro-cracks in the composite ceramic are shorter and more tortuous. The weak interface between the YSZ and La2Zr2O7 results in the nucleation and tortuous propagation of micro-cracks, which depletes part of the energy and improves the fracture toughness of the composite ceramic. The results reveal that the La2Zr2O7@YSZ composite ceramic has good mechanical and thermophysical properties.
Source: openaire · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Nuclear Materials and Properties · Nuclear materials and radiation effects · High-Temperature Coating Behaviors
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (32)
Show source-provided references
1. Evaluation of microstructural evolution of thermal barrier coatings exposed to Na2SO4 using impedance spectroscopy10.1016/j.corsci.2010.12.023 ↗
2. Thermal and mechanical properties of Ta2O5 doped La2Ce2O7 thermal barrier coatings prepared by atmospheric plasma spraying10.1016/j.jeurceramsoc.2019.02.041 ↗
3. Prediction of critical rupture of plasma-sprayed yttria stabilized zirconia thermal barrier coatings under burner rig test via finite element simulation and in-situ acoustic emission technique10.1016/j.surfcoat.2019.03.063 ↗
4. Plasma-sprayed nanostructured scandia-yttria and ceria-yttria codoped zirconia coatings: microstructure, bonding strength and thermal insulation properties10.1016/j.ceramint.2018.03.204 ↗
5. Mohammad Reza Loghman-Estarki, Morteza Hajizadeh-Oghaz, Hossein Edris, Reza Shoja Razavi, Comparative studies on synthesis of nanocrystalline Sc2O3-Y2O3 doped zirconia (SYDZ) and YSZ solid solution via modified and classic Pechini method,CrystEngComm, Vol. 15(29): 5898-5909.10.1039/c3ce40288f ↗
6. LZC/YSZ DCL TBCs by EB-PVD: microstructure, low thermal conductivity and high thermal cycling life10.1016/j.jeurceramsoc.2018.12.031 ↗
7. Preparation and thermophysical properties of plasma sprayed lanthanum zirconate10.1016/j.matchemphys.2017.10.031 ↗
8. Preparation and thermophysical properties of La2(Zr0.7Ce0.3)2O7 ceramic via sol-gel process10.1016/j.surfcoat.2012.09.026 ↗
9. Synthesis kinetics and thermophysical properties of La2(Zr0.7Ce0.3)2O7 ceramic for thermal barrier coatings10.1016/S1002-0721(12)60028-3 ↗
10. Structure, phase stability and thermophysical properties of (Yb0.1La0.9)2(Zr0.7Ce0.3)2O7 ceramics10.1016/j.matlet.2014.07.162 ↗
11. (Y005La0.95)2(Zr0.7Ce0.3)2O7 ceramics as a thermal barrier coating material for high-temperature applications10.1016/j.matlet.2013.11.039 ↗
12. Fabrication and phase transition of La2−xLuxZr2O7 transparent ceramics10.1016/j.jeurceramsoc.2014.05.046 ↗
13. Effects of doping on thermal conductivity of pyrochlore oxides for advanced thermal barrier coatings10.1016/j.msea.2007.01.069 ↗
14. Effect of rare earth doping on thermo-physical properties of lanthanum zirconate ceramic for thermal barrier coatings10.1016/S1002-0721(09)60002-8 ↗
15. Thermal and mechanical stability, electronic structure and energetic properties of Pu-containing pyrochlores: La2-yPuyZr2O7 and La2Zr2-yPuyO7 (0≤y≤2)10.1016/j.jnucmat.2015.07.051 ↗
16. Glass-like thermal conductivities in (La1-x1Yx1)2(Zr1-x2Yx2)2O7-x2 (x = x1 + x2, 0 ≤x ≤1.0) solid solutions10.1016/j.actamat.2012.08.063 ↗
17. Preparation and thermophysical properties of (Sm0.5La0.5)2Zr2O7 and (Sm0.5La0.5)2(Zr0.8Ce0.2)2O7 ceramics for thermal barrier coatings10.1016/j.jallcom.2008.07.068 ↗
18. Role and determining factor of substitutional defects on thermal conductivity: a study of La2(Zr1−xBx)2O7 (B = Hf, Ce, 0<x<0.5) pyrochlore solid solutions10.1016/j.actamat.2014.01.011 ↗
19. Isothermal oxidation and thermal cyclic behaviors of YSZ and double layered YSZ/La2Zr2O7 thermal barrier coatings (TBCs)10.1016/j.surfcoat.2018.07.069 ↗
20. Novel double-ceramic-layer (La0.8Eu0.2)2Zr2O7/YSZ thermal barrier coatings deposited by plasma spraying10.1016/j.ceramint.2014.03.159 ↗
21. Microstructures and properties of double-ceramic-layer thermal barrier coatings of La2(Zr0.7Ce0.3)2O7/8YSZ made by atmospheric plasma spraying10.1016/j.apsusc.2015.02.173 ↗
22. Lanthanum zirconate ceramic toughened by BaTiO3 secondary phase10.1016/j.jallcom.2006.11.025 ↗
23. Effective blocking of radiative thermal conductivity in La2Zr2O7/LaPO4 composites for high temperature thermal insulation applications10.1016/j.jeurceramsoc.2016.03.010 ↗
24. Investigation of a new type of composite ceramics for thermal barrier coatings10.1016/j.matdes.2016.09.050 ↗
25. The effect of sintering temperature on the microstructure and phase transformation in tetragonal YSZ and LZ/YSZ composites10.1016/j.ceramint.2015.10.046 ↗
26. Microstructure and mechanical properties of La2Zr2O7-(Zr0.92Y0.08)O1.96 composite ceramics prepared by spark plasma sintering10.1016/j.ceramint.2014.05.121 ↗
27. Ferroelastic domain switching toughening in spark plasma sintered t’-yttria stabilized zirconia/La2Zr2O7 composite ceramics10.1016/j.ceramint.2017.06.121 ↗
28. Thermal barrier coatings with Al2O3-Pt composite bond-coat and La2Zr2O7-Pt top-coat prepared by cathode plasma electrolytic deposition10.1016/j.surfcoat.2016.02.036 ↗
29. An experimental study of the planetary ball milling effect on dispersibility and thermal conductivity of MWCNTs-based aqueous nanofluids
30. Thermal radiation and conduction in functionally graded thermal barrier coatings. Part II: experimental thermal conductivities and heat transfer modeling10.1016/j.ijheatmasstransfer.2019.01.017 ↗
31. Thermal conductivity of dense and porous yttria-stabilized zirconia10.1023/A:1017970924312 ↗
32. Tailored microstructures of gadolinium zirconate/YSZ multi-layered thermal barrier coatings produced by suspension plasma spray: durability and erosion testing