Abstract: A method of creating an article from investment casting includes forming a ceramic seed well, heating the ceramic seed well to form a hardened ceramic seed well, attaching a meltable pattern to the hardened ceramic seed well, coating the hardened ceramic seed well and the meltable pattern with hardenable ceramic material, heating the hardenable ceramic material to melt the meltable pattern, removing the meltable pattern from the hardenable ceramic material, firing the hardenable ceramic material to form a ceramic mold having a cavity, placing a seed within the hardened ceramic seed well, and pouring molten metal into the hardened ceramic seed well and the cavity. The cavity of the ceramic mold is in communication with the hardened ceramic seed well.

Abstract: In an investment casting process, a composite core is formed as a combination of ceramic casting core element and a non-ceramic casting core element. The core is heated in an oxidative atmosphere and then heated in a non-oxidative atmosphere.

Abstract: A refractory metal core for use in a casting system has a coating for providing oxidation resistance during shell fire and protection against reaction/dissolution during casting. In a first embodiment, the coating includes at least one oxide and a silicon containing material. In a second embodiment, the coating includes an oxide selected from the group of calcia, magnesia, alumina, zirconia, chromia, yttria, silica, hafnia, and mixtures thereof. In a third embodiment, the coating includes a nitride selected from the group of silicon nitride, sialon, titanium nitride, and mixtures thereof. Other coating embodiments are described in the disclosure.

Abstract: An article may be manufactured by providing a reticulate core element in a mold shell having a shape at least partially corresponding to a shape of the article. The molten metallic material is introduced to the shell so as to at least partially infiltrate into the reticulate core element. The molten metallic material is permitted to solidify. The shell and the reticulate core element are destructively removed. The removal leaves the article with one or more gas-permeable porous regions.

Abstract: An apparatus for shelling an investment casting pattern has a tank containing a coating material. There are means for holding the pattern immersed in the coating material. There may be means for vibrating the pattern during immersion of the pattern and a vacuum source coupled to the tank to withdraw air from at least one headspace of the tank.

Abstract: An apparatus for shelling an investment casting pattern has a tank containing a coating material. There are means for holding the pattern immersed in the coating material. There may be means for vibrating the pattern during immersion of the pattern and a vacuum source coupled to the tank to withdraw air from at least one headspace of the tank.

Abstract: The invention is a process for removing ceramic thermal barrier layers from gas turbine engine hardware. A combination of chemical and mechanical steps are used to remove the thermal barrier coating from the substrate without removing the bond coat from the substrate. The process leaves the bond coat on the substrate in condition to receive a repair ceramic thermal barrier coating. The process includes a caustic solution treatment in an autoclave under controlled conditions followed by a mechanical abrasion process.

Abstract: An electro-optical contact assembly provides a connection between an electrical system and a fiber optic system for transmission of a signal therethrough. The assembly includes a converter for converting the signal between electrical and optical forms. The assembly also includes a receptacle with a retention mechanism mounted thereon which allows secure retention of an optical fiber terminus in the receptacle. The retention mechanism allows manual release of its clip from engagement with the optical fiber terminus in order to allow removal of the terminus from the receptacle, thereby allowing optical connection and disconnection of the assembly from the electrical system as well as other systems by simply plugging and unplugging fiber optic termini into and out of the contact assembly. The assembly includes a conductor surrounding the receptacle and terminus to provide EMI and RFI shielding of the terminus.

Abstract: A coated nickel base superalloy single crystal turbine airfoil blade (1), which is subject to gas turbine engine operation, can crack during refurbishment by a stress corrosion mechanism when exposed to certain corrosive media. The rapid thermal cycling that occurs during typical gas turbine engine operation results in high, non-uniform stresses across the airfoil, producing large localized residual strains in the article at ambient temperatures. Exposure to a corrosive environment, such as during coating removal or agressive cleaning, can produce chordwise cracks in a large number of the airfoils exposed. Such cracking is avoided by subjecting the articles to a preliminary stress relieving heat treatment which reduces the residual strains to a level below which cracking will not occur, prior to exposure to the corrosive media.