Abstract: The method involves removing wax from a substrate using a non-chlorinated solvent process. The substrate is dipped in a hot wax bath or heated in an oven to remove substantially all of the wax. The substrate is then submerged in either a single or a series of hot mineral oil baths to remove any remaining wax. The oil is then removed by a semi-aqueous or light organic cleaner. The semi-aqueous cleaner is subsequently removed in an alkaline-base cleaner bath. Following the alkaline-base cleaner is a cleansing with a rinsing solution preferably a countercurrent series of rinses. Finally, the substrate is dried.

Abstract: This invention relates to a method for making porous metal plasma sprayed abradable seals. Radiation transmission techniques are utilized to determine the as-sprayed density of a deposit containing metal and polymer powder particles. Based on the measuring density, a mathematical prediction is made of what the surface hardness of the sprayed deposit will be after it has been machined and then heated to remove the polymer powder particles. If the predicted hardness is outside of the desired range, changes are made in the plasma spray parameters.

Abstract: Apparatus for delivering two or more powders at any controlled ration to a thermal spray apparatus permits the controlled production of graded sprayed coatings. The apparatus also monitors and controls the position of the spray apparatus relative to the workpiece and varies this position during the deposition of the sprayed layers. The apparatus includes in-process mass flow gauges which measure in real time the flow rates of the various powders and report these rates to a supervisory controller which verifies these rates against the predetermined schedule and can shut down the apparatus in the event of a malfunction. The substrate being sprayed has its substrate temperature monitored and controlled according to a predetermined schedule by a supervising controller.

Abstract: Accurate measurements are made of powder entrained in a flowing gas stream. Measurements are made of the flowing gas stream prior to powder entrainment and x-ray measurement techniques are made to determine characteristics of the combined materials. An equation is disclosed for calculating the mass flow rate of the powder material from these measurements.