Improvements in and relating to the coating of articles by means of cathode disintegration

Abstract

Abstract 488,131. Depositing substances by electric discharge. BERGHAUS, B. May 27, 1937, Nos. 14761 and 14762. Convention dates, May. 27, 1936 and June 17, 1936. [Class 41] In coating articles by cathode disintegration in a vacuum the disintegrated particles are collected or clustered by a magnetic Seld arranged so as to direct them along its lines of force towards the article. The apparatus shown in Fig. 7 comprises a cathode 48 of metallic or non-metallic material to be disintegrated, and an annular anode 49 adjustable in a guide 58. The disintegrated particles are collected into a stream 51 by the field of a coil 50. The coil 50 may be water-cooled and may be insulated, e.g. by coating with an oxide layer. The beam may be diverted so as to cover the surface of the article by the transverse fields of electromagnets 59, 60. The article 40 is mounted on a metal plate 43 resting on insulating supports in a chamber 41 provided with gas supply and exhaust connections 61, 62, and connected to the discharge chamber by a ground joint 39. A door 45 is provided for insertion of the article. The plate 43 may be positively connected to serve as an accelerating electrode. For coating an extended article such as a band this may be mounted on rollers in a chamber having a number of parallel discharge chambers mounted above it ; the discharge chambers are provided with sliding doors whereby they may be shut off for replacement of the cathodes. The disintegrating chambers are provided with air-inlet cocks. The apparatus shown in Fig. 13 comprises two or more discharge chambers 103 communicating by sliding doors 107 with a common vessel 101 to which are connected chambers 99 housing the articles 109. The chambers 99 are provided with closing doors 108, hinged doors 111 for insertion and removal of the articles and gas and exhaust connections 112, 113. In other apparatus the field coil is mounted inside the discharge chamber. It may be adjustable in position. An arrangement in which two beams of particles are projected from the cathode in opposite directions is described. The concentration of the beam of disintegrated particles may be increased by passage through a negatively connected cylinder. The cathode may be heated by resistance or high-frequency heating. Arc heating may also be employed particularly in disintegrating vanadium, titanium, rhodium, hafnium, molybdenum, tungsten and rhenium. The heating and disintegration may be effected in alternating periods. The cathode may be hollow so as further to concentrate the beam and the material to be disintegrated may be arranged within it. The cathode may also consist of a cluster of metal wires arranged in the direction of the field. Selenium and carbon as well as metals and alloys may be disintegrated. The enclosed gas may be hydrogen, argon, neon, helium, hydrocarbons or silicon hydride at a pressure of 0À01- 1À0 mm. Specification 470, H 14 is referred to.

Inventors

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