Abstract: The present invention relates to novel binder and slurry formulations used to form molds for casting metal alloys and, more particularly, reactive metal alloys. The shell molds lead to more uniform castings which exhibit limited alpha case as compared to other currently available shell mold systems.

Abstract: A method for controlling the dewaxing of a ceramic investment casting shell assembly is provided whereby the shells are immersed in a fluid having a relatively low boiling point, e.g., below about 230° F. The fluid must be hot enough to transfer heat though the shell assembly so as to melt the wax pattern, but low enough so as to limit steam generation as a result of moisture in the shell. By controlling the rate of immersion of the shell in the hot fluid bath, shell cracking can be greatly reduced.

Abstract: The present invention relates to novel binder and slurry formulations used to form molds for casting metal alloys and, more particularly, reactive metal alloys. The shell molds lead to more uniform castings which exhibit limited alpha case as compared to other currently available shell mold systems.

Abstract: The present invention relates to novel binder and slurry formulations used to form molds for casting metal alloys and, more particularly, reactive metal alloys. The shell molds lead to more uniform castings which exhibit limited alpha case as compared to other currently available shell mold systems.

Abstract: The invention relates to a investment casting shell molds and their method of manufacture. The method entails mixing fiber and refractory filler to form a dry blend; mixing the dry blend with a binder sol to form a refractory slurry, and employing the refractory slurry to produce an investment casting shell mold.

Abstract: Incorporation of rice hull ash into investment casting shell molds improves the permeability, shell build thickness, and/or shell build uniformity of the molds. A method to make the molds entails mixing refractory filler, rice hull ash, and preferably a fiber to form a dry blend; mixing the dry blend with a binder sol to form a refractory slurry, and employing the refractory slurry to produce an investment casting shell mold.

Abstract: The invention relates to investment casting shell molds and their method of manufacture. The method entails mixing fiber such as ceramic refractory fiber and organic fiber with ceramic filler to form a dry blend. The dry blend is mixed with a binder sol such as colloidal silica sol to form slurry. An expendable preform is dipped into the slurry, stuccoed and dried. This step is repeated until a ceramic shell of a desired thickness is formed over the expendable preform. The expendable preform then is removed, and the green ceramic shell is fired. Molten metal then may be poured into the shell to form a metal casting.

Abstract: The invention relates to investment casting shell molds and their method of manufacture. The method entails mixing fiber such as ceramic refractory fiber and organic fiber with ceramic filler to form a dry blend. The dry blend is mixed with a binder sol such as colloidal silica sol to form slurry. An expendable preform is dipped into the slurry, stuccoed and dried. This step is repeated until a ceramic shell of a desired thickness is formed over the expendable preform. The expendable preform then is removed, and the green ceramic shell is fired. Molten metal then may be poured into the shell to form a metal casting.

Abstract: The invention relates to a investment casting molds and their method of manufacture. The method entails mixing refractory fiber, glass fiber, and refractory filler to form a dry blend; mixing the dry blend with an aqueous colloidal silica sol to form a refractory prime coat slurry, and employing the refractory slurry to produce an investment casting mold.

Abstract: The invention relates to a investment casting molds and their method of manufacture. The method entails mixing refractory fiber, glass fiber, and refractory filler to form a dry blend; mixing the dry blend with an aqueous colloidal silica sol to form a refractory prime coat slurry, and employing the refractory slurry to produce an investment casting mold.

Abstract: A process for rapidly forming a ceramic shell mold on an expendable pattern is disclosed. The process entails use of refractory slurries which include a large particle size colloidal silica sol binder. The colloidal silica sol binder has an average particle size of about 40 nanometers, i.e., about 3-4 times larger than colloidal silica sol binders heretofore employed in manufacture of ceramic shell molds. The use of the large particle sols yields unfired ceramic shell molds which have about 40% to about 70% greater unfired strengths compared to ceramic shells made with prior art small particle size silica sols. Prime coats and refractory back-up coats which use the large particle size sol dry about 30% to about 40% faster than prime coats and back up coats which employ the smaller particle size silica sols of the prior art.

Abstract: A process for rapidly forming a laminar ceramic shell mold on a supporting structure comprising alternately, in either order, the steps of: (1) dipping the support structure into a bath comprising either an alkali stabilized solution of ionic silicate or an alkali stabilized solution of colloidal silica to define a first coating on the support structure; and (2) dipping the support structure into a bath comprising an acid stabilized solution of phosphate modified aluminum salt to define a second coating on the support structure. The coatings on the support structure react to form a gel set shell which can be fired to create a ceramic material. The dipping step sequence is repeated to provide additional coatings which react to define additional layers of gel set shell. The rate of laminate thickness buildup can be increased by including fine particulate refractory in the coating baths and the coated surface can be contacted by dry, relatively coarse refractory to define a stucco layer between the dip coatings.

Abstract: A process for rapidly forming a laminar ceramic shell mold on a supporting structure comprising alternately, in either order, the steps of: (1) dipping the support structure into a bath comprising either an alkali stabilized solution of ionic silicate or an alkali stabilized solution of colloidal silica to define a first coating on the support structure; and (2) dipping the support structure into a bath comprising an acid stabilized solution of phosphate modified aluminum salt to define a second coating on the support structure. The coatings on the support structure react to form a gel set shell which can be fired to a ceramic material. The dipping step sequence is repeated to provide additional coatings which react to define additional layers of gel set shell. The rate of laminate thickness buildup can be increased by including fine particulate refractory in the coating baths and the coated surface can be contacted by dry, relatively coarse refractory to define a stucco layer between the dip coatings.