Abstract: Power supply of the saturable reactor type is disclosed. The improvement is the inclusion of a variable impedance network, such as a pair of opposed semiconductor controlled rectifiers, in series with the current winding of the saturable reactor. Also included is an electronic circuit for changing the impedance of the variable impedance circuit, such as a control circuit for monitoring an operating parameter and for enabling or disabling the firing of the semiconductor controlled rectifiers in response to a change in the operating parameter. A preferred embodiment of the power supply also includes a transformer and a rectifier for supplying high-voltage, direct current to a sputtering apparatus.

Abstract: A method is described for joining first and second surfaces by depositing a layer of metal on the first surface, preparing the second surface to expose fresh metal, placing the deposited metal and the exposed metal in contact, and applying sufficient pressure to join the surfaces, all done in a protective environment, such as vacuum. Also described is a related apparatus comprising an evacuable chamber, an electron-beam heated vapor source, and a pair of rollers for contacting and applying pressure to join the surfaces.

Abstract: An improved method is disclosed for coating substrates, such as turbine engine parts, at high rates by a physical vapor deposition process. The substrate to be coated and a vapor source, such as a metal alloy, heated by an electron beam, are placed in a chamber in which a gas pressure of greater than about 5 mT is maintained. When the source material is evaporated at a very high rate, such as greater than about 0.1 g/s or 13 g/s.m.sup. 2, the vapor is collimated and the collimation increases as the gas pressure or the evaporation rate increases. Collimation of the vapor allows a much higher deposition rate for a given evaporation power. Further, a much higher fraction of the evaporated material is deposited on the substrate. Despite the collimation, evaporated material deposits on areas of the substrate which are not in line-of-sight of the vapor source. If desired a substrate bias can be applied to bombard the substrate with ions before and during coating.