A mask, preferably for high temperature applications, such as flame spray processes, welding or soldering. The mask consists of an uppermost sacrificial layer formed of a high temperature resistant polymer, a perforated metal layer, preferably a metal screen bonded to the lower surface of the sacrificial layer, a barrier layer formed of a high temperature resistant polymer and bonded to the lower surface of the perforated metal layer, an adhesive layer applied to the lower surface of the barrier layer and a release layer covering the adhesive until used. Additional layers and additives such as flame retardants may be used. A preferred additional layer is comprised of a vermiculite dispersion which is coated onto the top of the sacrificial layer.
An under-dimensioned surface on metal tooling used in repetitive high temperature formation of parts is repaired by application of a metallic coating by use of a metal arc spray system. The under-dimensioned area is first roughened, and then is bordered by a raised template spaced a short distance above the surface of the tool by shims. Next the metal spray coating is applied, followed by machining of the metal coating to the proper dimensions of the tool.
A masking tape for use in masking a part in a high velocity oxy-fuel (HVOF) plasma spray process. The tape is formed from a fabric which is tightly woven from yarns of aramid fibers. A silicone rubber impregnates the inner fabric layer. First and second silicone rubber layers are coated onto opposite sides of the impregnated fabric. A pressure-sensitive adhesive is coated onto the second silicone rubber layer, which is preferably laminated with a release liner.
In an apparatus for thermally spraying a coating on a work piece, an improvement is disclosed. The improvement comprises a flexible elastomeric mask for protecting the apparatus. The mask is made from silicone rubber having a composition comprising, silicone polymer in the range of about 40% to about 70% by weight, and silica in the range of about 30% to about 60% by weight.
A method for coating an article such as a turbine engine shroud with an environmental or bond coating, such as a MCrAlY composition, to produce a surface finish suitable for machining to predetermined dimensions and specifications. The method of applying an environmental or bond coating uses a thermal spray process such as hyper velocity oxygen fuel ("HVOF") to produce a thick and reasonably uniform coating which can be machined to desired dimensions while still providing key quality characteristics required to protect the coated parts in a high temperature, oxidative and corrosive atmosphere and permitting application of long life thermal barrier topcoats.
The present invention provides a method for forming a coherent vermiculite film which can be performed on a continuous basis. An exemplary method comprises the steps of providing a non-flocculated dispersion of delaminated vermiculite platelets, providing a flexible release carrier having a surface operative for retaining thereupon a wet film of said dispersion and further operative for releasing the vermiculite film when dried, applying a wet vermiculite film to the moving carrier, and drying the vermiculite film, whereby the dried film is releasable from the carrier. The flexible release carrier preferably comprises paper having a release agent coating thereon. The invention also provides a flexible carrier-supported releasable vermiculite film, a film made from an vermiculite-aziridine composition, a composition of vermiculite and an aziridine, and a composition of vermiculite and amine resulting from an aziridine.
