Abstract: Electrochemical machining method and apparatus wherein in one aspect of the invention, the machining voltage is selected to maintain the highest current without initiating substantial hydrolysis of the electrolyte flushed between the work piece anode and tool cathode. In another aspect of the invention, the Low Machining Potential Voltage (LPMV) and High Machining Potential Voltage (HMPV) for a particular work piece material are identified and the work piece is machined using a voltage at or between the LMPV and HMPV. In yet another aspect of the invention, direct perturbation of the Beta Insulating Layer (BIL) is carried out in an optimally small (between about near zero to about 10?) inter-electrode gap (IEG) with constant and simultaneous pulling in and pushing out of the electrolyte through the IEG.

Abstract: Electrochemical machining method and apparatus wherein in one aspect of the invention, the machining voltage is selected to maintain the highest current without initiating substantial hydrolysis of the electrolyte flushed between the work piece anode and tool cathode. In another aspect of the invention, the Low Machining Potential Voltage (LPMV) and High Machining Potential Voltage (HMPV) for a particular work piece material are identified and the work piece is machined using a voltage at or between the LMPV and HMPV. In yet another aspect of the invention, direct perturbation of the Beta Insulating Layer (BIL) is carried out in an optimally small (between about near zero to about 100 inter-electrode gap (IEG) with constant and simultaneous pulling in and pushing out of the electrolyte through the IEG.

Abstract: A method for fabricating electrically conductive silicon carbide articles by doping and sintering submicron silicon carbide particles using sub-micron alumina as the dopant source. Submicron alumina particles are made by milling aluminum powder. Despite the ductility of metallic aluminum, it is successfully ball milled in an aqueous medium through the creation and abrasion of successive layers of an alumina skin to yield alumina particles as small as 0.01 &mgr;m across. When suitably composed mixtures of the silicon carbide and alumina are molded into a green body and heated sufficiently in a non-oxidizing furnace atmosphere, the alumina breaks down to metallic aluminum which diffuses into the silicon carbide. The small particle sizes and the presence of a sintering aid enable rapid processing kinetics which favor saturation of the silicon carbide by the aluminum and inhibit grain growth.

Abstract: An electrical discharge machining (EDM) apparatus and method is disclosed that utilizes a rotating electrode for performing the EDM operation to form a desired profile in the work piece surface. A dressing tool located at a side of the rotating electrode opposite from the work piece is operable to dress the surface of the rotating electrode. Operation of the dressing tool is controlled in part by a monitor that monitors changes in the character and condition of the surface of the rotating electrode from certain starting parameters and initiates a dressing operation as needed to restore the starting parameters.