Abstract: An electrode assembly has an inner conductor removably connected to an insulating layer. The inner electrode is removable so that the discharge tip may be replaced without destroying the insulating layer and thus reused. In the preferred embodiment external threads on the inner conductor cooperate with internal threads in a bore of the insulating layer to fixably secure the insulating layer in a desired position relative to the inner conductor and discharge electrode tip. The discharge electrode is located colinearly with a grounded electrode tip spaced by a spark gap. The grounded electrode tip is also configured to be easily removed from the electrode assembly for replacement when degraded.

Abstract: A method and apparatus for electroplating the surface of a conductive substrate using an electroplating solution having a low concentration of plating ions. Forward and reverse polarity current pulses are alternatively provided between the part to be plated and an anode in an electroplating bath. The process voltage, V.sub.p, between the part to be plated and the anode is sensed and the time ratio between the forward and reverse current pulses is varied to maintain the process voltage V.sub.p below a burn voltage V.sub.b.

Abstract: Improved performance for a deoxidizer solution is achieved by adding ammonium nitrate to a mixture of nitrate, sulfate, and ammonium bifluoride. Gelling or thickening of the deoxidizer is achieved by adding fumed silica to the mixture, with or without ammonium nitrate.

Abstract: Disclosed is a method and apparatus for electrolytic processing of a metal surface which, in a preferred embodiment, is anodization of an aluminum or aluminum alloy surface. An apparatus and method is provided which automatically senses the process voltage applied to the surface to be anodized and adjusts the duration of anodizing current pulses accordingly. Direct current anodizing pulses are interrupted by non-anodizing pulses which may be either zero current or reverse current pulses. The ratio of anodizing to non-anodizing pulse power is varied during anodizing such that the anodizing to non-anodizing time power ratio is reduced. In a preferred embodiment, a microprocessor follows the process voltage necessary to maintain a constant current flow to the metal surface and reduces the anodizing to non-anodizing time power ratio in a predetermined manner.

Abstract: Disclosed is a method and apparatus for electrolytic processing of a metal surface which, in a preferred embodiment, is anodization of an aluminum or aluminum alloy surface. An apparatus and method is provided which automatically senses the process voltage applied to the surface to be anodized and adjusts the duration of anodizing current pulses accordingly. Direct current anodizing pulses are interrupted by non-anodizing pulses which may be either zero current or reverse current pulses. The ratio of anodizing to non-anodizing pulse power is varied during anodizing such that the anodizing to non-anodizing time power ratio is reduced. In a preferred embodiment, a microprocessor follows the process voltage necessary to maintain a constant current flow to the metal surface and reduces the anodizing to non-anodizing time power ratio in a predetermined manner.

Abstract: An improved tank process for plating aluminum substrates which is especially advantageous for plating porous aluminum castings and, blister-free plated aluminum substrates produced thereby, characterized in that the aluminum piece parts are: (i) emulsion cleaned in a room temperature alkaline cleaner; (ii) immersed in a room temperature dilute acid, inorganic, fluoride salt solution to dissolve heavy oxides and surface silicon while minimizing etching and intergranular attack of the aluminum substrate such, for example, as a porous cast aluminum substrate; (iii) immersed in a room temperature dilute zincate bath for applying a relatively thin zinc protective coating, preferably utilizing a double zincate immersion process with an intermediate prolonged (1-3 min.) nitric acid soak to reduce the zincate deposition rate and to thereby provide improved zincate adhesion; (iv) plated with a non-porous strike applied directly on the zincate protective coating--e.g.

Abstract: An anodizing process having a suspended cathode having a casing of non-electrically conductive material to shield the upper portion of the cathode from effective anodizing communication with the electrolytic bath. The shield can be positioned selectively relative to the length of the cathode whereby the effective area of electrolytic communication can be controlled.