Ca-Mn co-doping LaCrO3 coating with high emissivity and good mechanical property for enhancing high-temperature radiant heat dissipation. Issue 15 (December 2022)

• Record Type: Journal Article
• Authors: Zhang, Haipeng; Wang, Chao; Wang, Yaming; Wang, Shuqi; Chen, Guoliang; Zou, Yongchun; Deng, Chunming; Jia, Dechang; Zhou, Yu
• Is Part Of: Journal of the European Ceramic Society. Volume 42:Issue 15(2022)
• Page Start: 7288
• Page End: 7299
• Publication Date: 2022-12
• Subjects: LaCrO3 coating -- Electrostatic spray -- Infrared emissivity -- Nanoindentation -- Atmospheric plasma spraying; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2022.08.033
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: Two techniques, including spray drying and electrostatic spray, were applied to produce feedstocks for preparing Ca-Mn co-doping LaCrO3 ceramic coatings with two different structures on Ni-based alloy by the atmospheric plasma spraying method. The results show that coating from feedstocks produced by spray drying exhibits lower roughness and porosity than the coating from feedstocks produced by electrostatic spray due to the full melting of smaller feedstocks. Higher proportion of melting zones is beneficial to enhance the ratio of hardness to modulus to improve wear resistance. The emissivity of the coatings with roughness from 0.65 µm to 4.6 µm is all above 0.9 in the waveband of 1–14 µm at room temperature. What's more, structure-dependent emissivity is affected by surface roughness and pore size due to the infrared scattering. The temperature-dependent thermal infrared emissivity at 1–14 µm decreases with the increasing temperature, and is still above 0.67 at 1200 °C. Highlights: Feedstocks with smaller size can reduce the porosity and enhance the mechanical properties of the coatings. The emissivity of Ca-Mn co-doping LaCrO3 ceramic coatings is above 0.9 at room temperature. Roughness, oxygen vacancies, impurity levels and lattice distortion are the crucial factors to regulate emissivity. The emissivity of many homogeneous materials with no phase change will decrease with the increasing temperature.