| 摘要 |
PURPOSE:To prevent a deterioration of emission, and obtain the cathode of high intensity and long life, by providing a suppressor layer, for suppressing a generation of middle layer, on surfaces of the base metal. CONSTITUTION:Between a base metal 3, composed of Ni-28wt%, W-0.4wt% and Zr, and a layer 6 of alkaline earth metal oxide, are provided a layer 4 of ZrO2 and layer 5 of Pt. The layer, consisting of this layer 4 of ZrO2 and layer 5 of Pt, suppresses a reaction caused between the base metal 3 and the alkaline earth metal oxide layer 6, resulting in a suppression of generation of the middle layer of W and Zr system. However, the layer of ZrO2 being an insulator, must be made in a thickness of 100-10000Angstrom for the particle of ZrO2 not to be closely coated on surfaces of the base metal 3, and the layer 5 of Pt made into a thickness range of 1000- 2000Angstrom . In this way, a deterioration of Ni fine particle being prevented, exfoliation of the alkaline earth metal oxide is prevented, thus a life of the Braun tube can be prolonged. |
