Zhangjiagang, China
Zhangjiagang, China

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Zhang J.,Wuhan University of Science and Technology | Fan X.,Wuhan University of Science and Technology | Lu L.,Wuhan University of Science and Technology | Hu X.,Suzhou Sagreon New Materials Co.
Materials Letters | Year: 2015

Ferrite-based infrared radiation coatings with high emissivity were obtained by plasma spraying on carbon steel substrate directly from the mixtures of Fe2O3, MnO2, Co2O3 and NiO powders without high-temperature roasting. It was investigated whether high-temperature roasting process for raw powders before spraying could affect the phase, microstructure and infrared emissivity of coatings. It was revealed that the ferrites with spinel structure could be synthesized directly during plasma spraying process without previous high-temperature roasting. The phases and microstructures of coatings prepared from raw powders and high-temperature roasted powders were similar, and the coating from high-temperature roasted powders presented a similar emissivity (0.76-0.88) to that from raw powders (0.73-0.85). The high-temperature roasting process can be omitted when ferrite-based infrared radiation coatings are prepared by plasma spraying, which can simplify the process, save energy and reduce costs. © 2015 Elsevier B.V. All rights reserved.


Lu L.,Wuhan University of Science and Technology | Fan X.,Wuhan University of Science and Technology | Zhang J.,Wuhan University of Science and Technology | Hu X.,Suzhou Sagreon New Materials Co. | And 2 more authors.
Applied Surface Science | Year: 2014

The ferrite-based amorphous coatings with high infrared radiation properties have been successfully prepared on the surface of carbon steel substrate by plasma spraying process. The phase, morphology, microstructure, thermal behavior and infrared emissivity were determined by X-ray diffraction, scanning electron microscopy, differential scanning calorimetry and infrared spectroscopy. The prepared coating could keep amorphous structure when the ambient temperature was below 700 °C and it would crystallize gradually with further increasing the temperature. The amorphous structure is confirmed to be constructive for improving the emissivity of ferrite-based coatings, especially in the 3-8 μm band. The emissivity of the amorphous coating obtained by plasma spraying was over 0.8 in 3-8 μ band at 800 °C, which was higher than that of the coating with same composition prepared by conventional brushing method. The excellent thermal shock resistance of the coatings makes them to be good candidates for sensible energy-saving materials, which could work for long term at 1000°C. © 2014 Elsevier B.V. All rights reserved.


Fan X.-A.,Wuhan University of Science and Technology | Lu L.,Wuhan University of Science and Technology | Wu C.-D.,Wuhan University of Science and Technology | Cai X.-Z.,Wuhan University of Science and Technology | And 2 more authors.
Fenmo Yejin Cailiao Kexue yu Gongcheng/Materials Science and Engineering of Powder Metallurgy | Year: 2014

Infrared radiation amorphous coatings based cordierite and ferrites for energy-saving were prepared on the surface of carbon steel by plasma spraying technology. The morphology, phase composition and structure of the composite infrared ceramics and coatings were investigated by scanning electron microscope and X-ray diffraction. The spectral emissivity of the coating was measured by infrared spectrometer. The adhesion strength between the coating and substrate was measured by scratching test. The thermal shock resistance of the coating was tested by watering cooling. The results show that the cordierite-ferrite based infrared radiation coatings on the surface of carbon steel prepared by plasma spraying exhibit typical laminated structure with low porosity, and the adhesion strength between the coating and substrate is identified as the first level. The thermal shock resistance and emissivity values of 0.8 in 3~5 μm band of the obtained amorphous coating are higher than those of the traditional brushing coating, and the emissivity in wavelength 8~10 μm can reach 0.94.


Lu L.,Wuhan University of Science and Technology | Fan X.-A.,Wuhan University of Science and Technology | Hu X.-M.,Suzhou Sagreon New Materials Co. | Zhang J.-Y.,Wuhan University of Science and Technology
Fenmo Yejin Cailiao Kexue yu Gongcheng/Materials Science and Engineering of Powder Metallurgy | Year: 2015

Cordierite-ferrites based infrared radiation composite ceramics were prepared by microwave heating using Fe2O3, MnO2, CuO, Co2O3, and Mg2Al4Si5O18 powders as raw materials. The effect of chemical components on microstructure and properties of composite ceramics was investigated. The phase composition, structure, thermal dynamic properties, and emissivity of the prepared composite materials were investigated by X-ray diffraction, thermal gravimetric and differential thermal analysis, and infrared spectroscopy, respectively. The results show that the synthesized ferrite has mixed spinel structure, for ceramics with mass fraction of 10% ferrites, the spinel phases containing Mn3+ in the synthesized ferrites decrease with the increasing of Fe2O3 and the decreasing of MnO2, but the quality ratio of Fe2O3 to MnO2 has a little influence on the infrared radiation performance. When the quality ratio of Fe2O3 to MnO2 is 3:1, with increasing ferrites, the diffraction peaks of cordierite exhibit a shift towards small angle and the interplanar distance of cordierite increases, and accordingly the emissivity of the composite ceramic increases, especially the emissivity of the ceramic containing 30% ferrites is 0.85~0.89 in 8~14 μm band at 300 ℃. Moreover, the synthesized cordierite-ferrite based infrared radiation ceramic shows an excellent thermal stability, which is capable of working long term at 1300 ℃. ©, 2015, Central South University. All right reserved.


Zhang J.,Wuhan University of Science and Technology | Fan X.,Wuhan University of Science and Technology | Lu L.,Wuhan University of Science and Technology | Hu X.,Suzhou Sagreon New Materials Co. | Li G.,Wuhan University of Science and Technology
Applied Surface Science | Year: 2015

Starting from Fe2O3, MnO2, Co2O3 and NiO powders, the ferrites based infrared radiation coatings with high emissivity and high thermal shock resistance were successfully prepared on the surface of carbon steel by high velocity oxy-fuel spraying (HVOF). The coating thickness was about 120-150 μm and presented a typical flat lamellar structure. The coating surface was rough and some submicron grade grains distributed on it. The infrared emissivity of the ferrites based coating by HVOF was over 0.74 in 3-20 μm waveband at 800 °C, which was obviously higher than that of the coating by brushing process in the short waveband. The bonding strength was 30.7 MPa between the coating and substrate, which was five times more than that of conventional coatings by brushing process. The combined effect of the superior bonding strength, typical lamellar structure, pre-existing microcracks and newly generated pores made the cycle times reach 27 when the coating samples were quenched from 1000 °C using water. Lastly, the infrared radiation coatings were applied on the underside of household kettle, and the energy-saving efficiency could reach 30.5%. The ferrites based infrared radiation coatings obtained in this work are good candidates for saving energy in the field of cookware and industrial high temperature furnace. © 2015 Elsevier B.V. All rights reserved.

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