Abstract
Abstract In order to optimize the synthesis process of barium-calcium-aluminate (BCA) for the application of impregnated dispenser cathodes, the influence of two precipitants, ammonium carbonate (AC) and ammonium hydrogen carbonate (AHC), on the chemical composition, phase transformation, thermal behaviors and morphology of the precursors was systematically investigated by means of XRD, TG-DSC, FESEM, and EDS mapping analysis. The results revealed that AC precipitant facilities to form NH4Al (OH)2CO3 (AACH) phase and barium calcium carbonate in the precursor, while the product precipitated by AHC comprises amorphous γ-AlOOH phase and the carbonate. Both precursors precipitated by the AC and AHC undergo various stages of phase transformations and finally converted to an emission-active material Ba3CaAl2O7 phase after sintering at 1200 °C. DC emission current values have been measured and the maximum space charge limited current densities are 8.0 ± 0.3 and 6.5 ± 0.4 A/cm2 at 1130 °Cb for the testing cathodes impregnated with the AC and AHC precursor aluminates, respectively. The difference in the emission capacity originates from the barium content in the aluminates prepared with different precipitants.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
