Journal Article

Influence of HfO2 alloying effect on microstructure and thermal conductivity of HoTaO4 ceramics

Chen, Lin, Feng, Jing

2019

Overview

HfO 2 alloying effect has been applied to optimize thermal insulation performance of HoTaO 4 ceramics. X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy are employed to decide the crystal structure. Scanning electronic microscopy is utilized to detect the influence of HfO 2 alloying effect on microstructure. Current paper indicates that the same numbers of Ta 5+ and Ho 3+ ions of HoTaO 4 are substituted by Hf 4+ cations, and it is defined as alloying effect. No crystal structural transition is introduced by HfO 2 alloying effect, and circular pores are produced in HoTaO 4 . HfO 2 alloying effect is efficient in decreasing thermal conductivity of HoTaO 4 and it is contributed to the differences of ionic radius and atomic weight between Hf 4+ ions and host cations (Ta 5+ and Ho 3+ ). The least experimental thermal conductivity is 0.8 W·K −1 ·m −1 at 900 °C, which is detected in 6 and 9 mol%-HfO 2 HoTaO 4 ceramics. The results imply that HfO 2 –HoTaO 4 ceramics are promising thermal barrier coatings (TBCs) due to their extraordinary thermal insulation performance.

• Publisher: Tsinghua University Press
• Subject: alloying effect / Alloying effects / Atomic properties / Atomic radius / Cations / Ceramic coatings / Ceramics / Characterization and Evaluation of Materials / Chemistry and Materials Science / Composites / Crystal structure / Glass / Hafnium oxide / Heat conductivity / Heat transfer / Holmium / Materials Science / Microstructure / Nanotechnology / Natural Materials / optical property / Photoelectrons / Raman spectroscopy / rare earth tantalates / Research Article / Spectrum analysis / Structural Materials / thermal barrier coating (TBC) / Thermal barrier coatings / Thermal conductivity / Thermal insulation / X ray photoelectron spectroscopy