碳纤维纸的电热性能研究

通过优选分散剂的方式改善碳纤维纸的匀度,制备出温度分布均匀的碳纤维纸,探讨了分散剂对碳纤维纸匀度性能的影响,以及碳纤维纸电阻对电热性能的影响。采用尘埃匀度仪、热成像仪等仪器对制备的碳纤维纸进行表征。结果表明,制备碳纤维纸时,加入用量0. 6%的阴离子聚丙烯酰胺(APAM)能够较明显地改善纸张匀度;碳纤维纸在通电加热条件下,电阻仅降低了2. 59%,纸张表面温差小于6℃,具有恒定功率的特征;碳纤维在纸张中的加入量为5. 0%左右,可以获得较高的远红外法向全发射率,在8～15μm波段纸张法向全发射率最高为83. 13%。     

High-Entropy Engineering for Broadband Infrared Radiation

Developing high-performance infrared (IR) radiation materials with desired broadband emissivity, excellent thermal stability, and scalable fabrication processes is highly desirable for energy-saving applications and heat dissipation. However, it remains a grand challenge to concurrently meet these requirements in existing IR radiation materials. Herein, a high-entropy (HE) approach is employed to advance the IR radiation performance of spinel oxide. This strategy efficiently narrows the bandgap due to the enhanced electron transitions and the introduction of oxygen vacancies (O_v), variable-valence behavior, and orbital hybridization. In addition, the lattice distortion effect lowers the symmetry of lattice vibration. Therefore, the resulting HE spinel oxide exhibits near-blackbody radiation performance, with its emissivity approximately three times higher than that of the binary spinel oxide. Moreover, the entropy-dominating phase stabilization effect contributes to impressive thermal stability (stable at 1300 °C for 100 h). This makes it suitable for high-temperature thermal radiation applications, such as energy conservation in industrial high-temperature furnaces. More importantly, the HE spinel oxide can be readily spray-coated on various substrates. And the coating on stainless steel reaches an outstanding emissivity of 0.943 in the 0.78−16 µm wavelength range. All these merits render the HE approach competitive for the development of high-emissivity and thermally stable thermal radiation materials.     

粒度对样品辐射特性影响的实验研究

利用IRE－1型红外辐射测量仪对不同粒度砂纸样品进行了（法向）光谱比辐射率的测试；测试波段为8－14um；测试温度分别为40℃、50℃ 和70℃ ，通过对测试结果的分析，指出在粒度尺寸大于测试波长时，随着颗粒尺寸的减小，样品的光谱比辐射率将减小，相应的8－14um的平均 比辐射也有减小的趋势。     

Band gap and oxygen vacancy engineering of honeycomb-like CuFe2O4 spinels toward enhanced high infrared emissivity

Recently, copper ferrites have acquired widespread attraction in high infrared radiation fields owing to their remarkable cost efficiency. However, to achieve broader applications under various operating conditions, it is essential to further improve the infrared emissivity, particularly at high temperatures. Herein, the Ni-doped CuFe₂O₄ (NCFO) honeycomb-like frameworks, which are constructed with single-crystal nano-subunits, are successfully fabricated via the scalable sol–gel avenue. The unique porous honeycomb framework endows NCFO with enhanced infrared absorption and relieves the stress between coatings and substrates meanwhile. With both band gap and oxygen vacancy (OV) engineering of CuFe₂O₄ itself via smart Ni doping, a maximum lattice strain, the richest OVs, and the narrowest band gap (∼1.63 eV) are simultaneously achieved for the CuFe₂O₄ with 15% Ni doping (denoted as CNFO-15). Benefiting from the synergy of these external and intrinsic contributions, the CNFO-15 possesses an ultrahigh infrared emissivity (∼0.975) in the wavelength range of 3–5 µm at a test temperature of 800°C. Moreover, the CNFO-15-based coating displays superior infrared radiation performance with outstanding high-temperature resistance. More meaningfully, the constructive design here will provide a distinctive perspective for future large-scale fabrication of advanced high-infrared-emissivity coatings.