Microstructure and Thermo-physical Properties of Plasma Sprayed LaTi2Al9O19 Thermal Barrier Coatings

HAO Weiwei; ZHENG Lei; GUO Hongbo; GONG Shengkai; XU Huibin

doi:10.7527/S1000-6893.2013.0244

ACTA AERONAUTICAET ASTRONAUTICA SINICA >

2013 , Vol. 34 >Issue 6: 1485 - 1492

DOI: https://doi.org/10.7527/S1000-6893.2013.0244

Material Engineering and Mechanical Manufacturing

Microstructure and Thermo-physical Properties of Plasma Sprayed LaTi₂Al₉O₁₉ Thermal Barrier Coatings

HAO Weiwei ,
ZHENG Lei ,
GUO Hongbo ,
GONG Shengkai ,
XU Huibin

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1. School of Materials Science and Engineering, Beihang University, Beijing 100191, China;
2. Beijing Key Laboratory for Advanced Functional Materials and Thin Film Technology, Beihang University, Beijing 100191, China

Received date: 2012-07-25

Revised date: 2012-09-18

Online published: 2012-09-25

Supported by

National Natural Science Foundation of China (51071013); National Basic Research Program of China(2010CB631200, 2012CB625100)

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Abstract

Conventional thermal barrier coatings (TBCs) consisting of a yttria stabilized zirconia (YSZ) ceramic coat and a metallic bond coat for industrial application cannot work long above 1 200℃. With aero-engines developing towards higher thrust-to-weight ratio, it is necessary to develop new ceramic coating materials with better thermal barrier performance for ultra-high temperature application. LaTi₂Al₉O₁₉ (LTA) was proposed as a promising candidate due to its excellent phase stability at temperatures above 1 500℃. In this paper, the LTA coatings were produced by atmospheric plasma spraying (APS) and their microstructures and thermo-physical properties were investigated. There were some amorphous phases in the as-sprayed coatings and crystallization of the coatings occurred at 860℃ and 1 130℃, respectively. Due to the volatilization of La₂O₃during spraying, the concentration of La in the sprayed coating was relatively lower than that in the powder, while the other elements didn't show apparent changes in the compositions. The thermal diffusivity of the LTA coatings ranged from 0.3 to 0.4 mm²·s^-1 at 1 400℃ and the corresponding thermal conductivity were in the range of 1.1 to 1.6 W·m^-1·K^-1. The coating porosity increased as the spraying power decreased, while the thermal conductivity decreased with increasing spraying power.

Key words： thermal barrier coatings; ceramic; LaTi₂Al₉O₁₉; plasma spraying; thermal conductivity

Cite this article

HAO Weiwei , ZHENG Lei , GUO Hongbo , GONG Shengkai , XU Huibin . Microstructure and Thermo-physical Properties of Plasma Sprayed LaTi₂Al₉O₁₉ Thermal Barrier Coatings[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2013 , 34(6) : 1485 -1492 . DOI: 10.7527/S1000-6893.2013.0244

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