| 摘要 |
<p>PURPOSE:To enable a cathode tip to be used for a long period stably by laminating one after another in such a manner that on a tip consisting of the hexaboride single crystal of rare earth elements are placed a reaction barrier layer consisting of carbon and/or boron carbide, an intermediate layer consisting of the boride and/or carbide of IV a group or Va group transition metals, and a supporting metal layer consisting of a high-melting-point metal. CONSTITUTION:On a single crystal tip 1 consisting of the hexaboride of rare earth elements are laminated one after another a reaction barrier layer 2 consisting of carbon and/or boron carbide, an intermediate layer 3 consisting of the boride and/or carbide of IVa group or Va group transition metals, and a supporting metal layer 4 consisting of a high-melting-point metal. It is desirable that the thickness of the reaction barrier layer 2 is 2-10mum, and then, it is desirable that the thickness of the intermediate layer 3 and the supporting metal layer 4 are 20-80mum respectively, and further, it is desirable that the total thickness of each of these layers is 50-120mum. Thereby, the cathode tip 1 hardly comes off, and can be used for a long period.</p> |
