Abstract: The present invention relates to a method and apparatus for forming abrasive surfaces on the tips of a plurality of workpieces such as the tips of gas turbine airfoil blades. The method broadly comprises the steps of providing a mechanical masking device having a plurality of openings arranged around the circumference of the device, installing an array containing a plurality of workpieces to be coated within the mechanical masking device so that portions of the workpieces including the tips thereof extend through the openings, immersing the mechanical masking device with the installed array of workpieces in a tank containing a plating bath with a matrix material and an abrasive grit material in slurry form so that the workpieces lie in a substantially horizontal plane, and applying a current through the plating bath to form the abrasive surfaces on the tips of the workpieces. The mechanical masking device protects portions of the array from the coating operation.

Abstract: The present invention relates to a method and apparatus for forming abrasive surfaces on the tips of a plurality of workpieces such as the tips of gas turbine airfoil blades. The method broadly comprises the steps of providing a mechanical masking device having a plurality of openings arranged around the circumference of the device, installing an array containing a plurality of workpieces to be coated within the mechanical masking device so that portions of the workpieces including the tips thereof extend through the openings, immersing the mechanical masking device with the installed array of workpieces in a tank containing a plating bath with a matrix material and an abrasive grit material in slurry form so that the workpieces lie in a substantially horizontal plane, and applying a current through the plating bath to form the abrasive surfaces of the tips of the workpieces. The mechanical masking device protects portions of the array form the coating operation.

Abstract: The present invention relates to a method and apparatus for forming abrasive surfaces on the tips of a plurality of workpieces such as the tips of gas turbine airfoil blades. The method broadly comprises the steps of providing a mechanical masking device having a plurality of openings arranged around the circumference of the device, installing an array containing a plurality of workpieces to be coated within the mechanical masking device so that portions of the workpieces including the tips thereof extend through the openings, immersing the mechanical masking device with the installed array of workpieces in a tank containing a plating bath with a matrix material and an abrasive grit material in slurry form so that the workpieces lie in a substantially horizontal plane, and applying a current through the plating bath to form the abrasive surfaces on the tips of the workpieces. The mechanical masking device protects portions of the array from the coating operation.

Abstract: A method and apparatus for increasing blade fatigue strength in a turbine engine. The blades in the turbine engine are configured so as to reduce stress at the tip of the blades during operation of the turbine engine, thus increasing blade fatigue strength. This stress reduction helps to counteract the detrimental effect of abrasive tip coatings on blade fatigue strength. In one embodiment, the tip of the blade is chamfered in order to reduce the stress on the tip of the blade. An abrasive coating is then applied to the tip of the blade to assist the blade in seating into an abradable outer air seal. In another embodiment, an abrasive coating is applied to a center portion of the tip of the blade, with the periphery of the abrasive coating being set back from the opposing surfaces of the blade.

Abstract: A method for simultaneously removing and monitoring the removal of a metallic contaminant from the surface of a metallic workpiece is disclosed. The workpiece and a reference electrode are immersed in an electrically conductive cleaning solution. The potential difference between the workpiece and the reference electrode is periodically measured to generate a series of potential difference values. Differences between successive potential difference values of the series are quantified to generate a noise parameter value. The noise parameter value is compared to a reference value, wherein the reference value is indicative of a maximum allowable amount of contaminant, to determine if an amount of contaminant greater than the maximum allowable amount of contaminant is present on the surface of the workpiece.

Abstract: Gas depolarized cathodes having hydrophobic barrier layers for circulation electrolyte electrochemical cells; methods of making said cathodes; and methods of electrolyzing solutions of halide containing compounds using said electrodes. Typically, in electrochemical cells cathodes are oriented vertically resulting in significant electrolyte pressure against the cathode. The barrier layer comprising fluorocarbon polymer and carbon results in substantially no electrolyte leakage through the cathode when the electrolyte pressure is up to three pounds per square inch above ambient.

Abstract: Gas depolarized cathodes having hydrophobic barrier layers for circulation electrolyte electrochemical cells; methods of making said cathodes; and methods of electrolyzing solutions of halide containing compounds using said electrodes. Typically, in electrochemical cells cathodes are oriented vertically resulting in significant electrolyte pressure against the cathode. The barrier layer comprising fluorocarbon polymer and carbon results in substantially no electrolyte leakage through the cathode when the electrolyte pressure is up to three pounds per square inch above ambient.

Abstract: Ammonia gas is scrubbed from a gas stream in a bed of material soaked with acid, and the bed is regenerated by passing an oxygen containing gas therethrough. The preferred acid is phosphoric acid and the preferred support material is carbon in the form of porous particles. In a fuel cell system dual scrubbers alternately scrub ammonia from reform gas and are subsequently regenerated so as to provide the fuel cells with a continuous flow of substantially ammonia free hydrogen.