Factors affecting the phase composition of 612 aluminates for Ba–W cathode
| Autor: | Saisai Xu, Jinglin Li, Jianjun Wei, Yongbao Feng, Tai Qiu, Xiaoyun Li |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Scanning electron microscope 02 engineering and technology 010502 geochemistry & geophysics 021001 nanoscience & nanotechnology Condensed Matter Physics Microstructure 01 natural sciences Atomic and Molecular Physics and Optics Cathode Electronic Optical and Magnetic Materials Amorphous solid law.invention Differential scanning calorimetry Chemical engineering law Phase (matter) Gravimetric analysis Calcination Electrical and Electronic Engineering 0210 nano-technology 0105 earth and related environmental sciences |
| Zdroj: | Journal of Materials Science: Materials in Electronics. 29:16330-16337 |
| ISSN: | 1573-482X 0957-4522 |
| DOI: | 10.1007/s10854-018-9723-7 |
| Popis: | The precursor powder of 612 aluminates were synthesized by using liquid-phase co-precipitation method. The microstructure and formation mechanisms of the precursor powder were investigated through X-ray diffraction, thermal gravimetric, differential scanning calorimetry, and scanning electron microscope. The effects of the stacking states of the precursor powder, calcination temperature, and atmosphere on the phase compositions of 612 aluminates were also systematically studied. Results showed that the prepared precursor powder was a mixture of BaCO3, BaCa(CO3)2, and amorphous AlOOH, which with particle size ranging from 20 to 30 nm. The stacking states of the precursor powder considerably influenced the phase composition of aluminates. The pressed precursor tablet can ensure the final phase composition of aluminates was Ba3CaAl2O7. When the precursor powder was calcined in CO2 atmosphere at 1400 °C for 2 h, the phase composition included Ba5CaAl4O12, BaAl2O4, and BaCO3. When the calcination temperature was increased, the main crystalline phase of aluminates changed from Ba5CaAl4O12 to Ba3CaAl2O7 in flowing N2, Ar, and static air. The barium–tungsten cathode prepared by aluminates of Ba3CaAl2O7 phase showed better emissivity than that of Ba5CaAl4O12 phase. The current density of pulse emission at 1050 °C can reach 35.31 A/cm2. |
| Databáze: | OpenAIRE |
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