Controllable synthesis of ZnO with different morphologies and their morphology-dependent infrared emissivity in high temperature conditions

• Published in: Journal of alloys and compounds Vol. 804; pp. 503 - 510
• Main Authors: Guo, Tengchao, Xu, Guoyue, Tan, Shujuan, Yang, Zhihong, Bu, Honghan, Fang, Gang, Hou, Haili, Li, Jing, Pan, Lingyu
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 05.10.2019; Elsevier BV
• Subjects: Dielectric function; Emissivity; High temperature; High temperature conditions; Infrared emissivity; Infrared radiation; Lattice vibration; Morphology; Morphology-controlled synthesis; Zinc oxide; ZnO; High temperature conditions; Dielectric function; Morphology-controlled synthesis; ZnO; Infrared emissivity
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2019.07.011

Nowadays, the high temperature low infrared emissivity problem has been of increasing significance and attracting more attention owing to the widespread applications for high temperature conditions. One key solution for this problem is to study the mechanism of high temperature low infrared emissivity and then design the materials with low infrared emissivity at elevated temperature. This paper gives an introduction to the infrared emissivity of ZnO powders in 3∼5 μm waveband at elevated temperature with various well-defined morphologies, e.g. needle-, pencil-, flower-, and flat-like. Among these morphologies, flat-like ZnO powders exhibit the lowest infrared emissivity because they have the largest real part of the dielectric function. Additionally, the variation of electrons average scattering time and lattice vibration at various temperature determine the variation tendency of infrared emissivity with temperature. [Display omitted] •ZnO powders with various morphologies are prepared by facile wet chemistry method.•Flat-like ZnO exhibits the lowest emissivity because of its highest real part of dielectric function.•The emissivity vs. temperature presents a U-shaped curve, and it reaches to the lowest value of 0.41 at 500 °C.•The decrease of emissivity with temperature is originated from the decrease of electrons scattering time.•The increase of emissivity with temperature higher than 500 °C is attributed to the strong lattice vibration absorption.