| 摘要 |
PROBLEM TO BE SOLVED: To reduce the impurities left in trace in a carbonate powder and the impurities included in the preparing process of a suspension by executing a solid-liquid separating process for reducing particles insoluble to an organic solvent to a cathode raw material suspension to be applied to a cathode gas metal, which contains a carbonate, a binder and the organic solvent, and includes particles insoluble to the organic solvent. SOLUTION: A binder is dissolved in an organic solvent, and impurities in the binder is separated and reduced by filtering at a reduced pressure of 500-600 mmHg. An alkali earth metal carbonate powder is mixed to the organic solvent containing the resulting binder to manufacture a suspension. The suspension is further filtered to filter the impurities contained in the carbonate powder and the impurities included in the preparing process of the suspension. The suspension from which the impurities are reduced is applied onto a cathode base metal by means of spray or electrodeposition. Thus, the solid foreign matter in a cathode forming the electron radiation source of electron beam of a cathode-ray tube can be reduced. |
