| 摘要 |
1,166,927. Electrode materials and processing. CLAUDE. 14 April, 1967 [18 April, 1966], No. 17360/67. Heading H1D. A method of preparing an electrode which includes a portion having a surface containing thorium oxide, comprises heating the electrode in an atmosphere containing a hydrocarbon at a partial pressure of about 1 mm. Hg by passing an arc discharge between the electrode and a second electrode 16. The electrode comprises a thoriated W rod 4 on which one or two tungsten filaments 6 are wound, then covered with a coating 8 of powdered thoria, thorium, silica and a binder. The electrode is mounted in a glass bell 12 opposite the second electrode 16. The bell is purged with A then A containing naphthalene is introduced and an A.C. or D.C. arc initiated by contacting the electrodes. During the discharge the electrode is moved so that the cathode spot moves over all of the coating. The electrode is allowed to cool, arc heated and cooled in A. The surface may be surrounded with a metallic member formed with voids, slots or pores, e.g. a W helix. Two such electrodes and one or two auxiliary electrodes are mounted in a h.p. Hg vapour lamp containing A and Na, Th, In iodides. The lamp may be mounted in an evacuated envelope. |
