铝酸钡盐电子发射材料的研究

Study on Electron Emission Materials of Aluminates

摘要:

采用液相共沉淀法和机械混合法成功制备了阴极用(nBaO:nCaO: nAl2O3=6:1:2)铝酸盐，并研究了烧结温度对612铝酸盐的影响，同时探讨其烧结机制以及烧结过程中物相之间存在的化学反应。采用扫描电镜、能谱仪、X射线衍射仪和激光粒度分析仪对铝酸盐形貌、粒度分布以及物相变化进行了研究。结果表明：采用液相共沉淀法成功制备出亚微米粒径的准球形前驱粉末，D (n, 50)值仅为815 nm。前驱粉末经过高温烧结(1500 ℃b)后，得到了晶化程度高，主晶相为Ba5CaAl4O12的612铝酸盐，浸渍钡钨阴极后，1100 ℃b下的发射电流密度达15.56 A/cm-2，蒸发速率仅为14.5 nm/h

Abstract:

The 612 aluminates were prepared by liquid phase co-precipitation and mechanical mixing. The effect of sintering temperature on the phases of the 612 (BaO:CaO:Al2O3=6:1:2) aluminate, the sintering mechanism and some chemical reactions during the sintering process were investigated. The shape, particle size distribution and phase transform of the aluminates were studied by scanning electron microscope (SEM), Energy Dispersive Spectrometer (EDS), X-ray diffraction (XRD) and laser particle size analysis. The result shows that the submicron quasi-spherical precursor particles with the D (n, 50)(nm) of 815 nm can be produced through the method of liquid phase co-precipitation. Using the obtained precursor, the 612 aluminates with high degree of crystallization and the crystal phase of Ba5CaAl4O12 can be produced after high temperature sintering at 1500 ℃b. The emission current density for Ba-W cathode (impregnated 612 aluminates) reaches to 15.56 A/cm2 with average evaporation rate of 14.5 nm/h