| 摘要 |
PURPOSE:To obtain a base metal, with which the initial performance of a directly heated cathode can be maintained for a long period of time, by mixing Ni powder and Mg powder in a given ratio by weight, and interposing the mixture between base metals by spraying or something similar so as to join the said base metals. CONSTITUTION:A Ni-W alloy containing no reducing agents, an alloy prepared by replacing part of W contained in the above Ni-W alloy with Mo, or an alloy prepared by replacing part of Ni contained in the above Ni-W alloy with Co is added and mixed with a reducing agent, which is prepared by mixing Mg powder and Ni powder in a ratio by weight of 100 to 0.5-20 by use of a solvent, so as to prepare a mixture. After that, the mixture is evenly applied between base metals by brush painting or spraying, and is heated in an atmosphere of hydrogen gas, an inactive gas or vacuum so as to make the base metals to be joined. By the means mentioned above, an excellent base metal, with which the initial performance of a directly heated cathode can be maintained for a long period of time, can be obtained. |
