Abstract: A quasi-single phase or single phase thick platinum nickel aluminide coating and methods for forming the coating over a nickel-based superalloy substrate are provided. The method includes the steps of forming a metal layer over a surface of the nickel-based superalloy substrate, the metal layer comprising platinum, growing a diffusion zone comprising a platinum nickel alloy layer from the metal layer and the nickel-based superalloy substrate, and subjecting the platinum nickel alloy to one or more aluminization cycles to transform the platinum nickel alloy into a platinum nickel aluminide coating having a platinum aluminide phase formed therein.

Abstract: Concentration and reclaiming of magnetic fluids is accomplished by (1) flocculation of the magnetic particles by addition of hydrochloric acid, (2) separation of the resulting flocculated particles, and (3) redispersion of the flocculated particles by addition of an aqueous suspension of ammonia, preferably with heating.

Abstract: The present invention provides a method for clarifying slimes. This method comprises the steps of treating a slime with a unique flocculant and separating the clarified slime from the aggregated floccules. The flocculant is a stabilized aqueous-base magnetic colloid that contains colloidal magnetic particles and at least one surfactant, such as dodecylamine. The magnetic colloid becomes unstable and the magnetic particles thereof irreversibly flocculate when the magnetic colloid is sufficiently diluted.

Abstract: A dilution stable water based magnetic fluid is provided by dispersing magnetic particles in water with the aid of a C.sub.10 -C.sub.15 aliphatic monocarboxylic acid. The magnetic particles are preferably particles of magnetite, prepared by precipitation of dissolved iron chloride salts from aqueous solution by the use of ammonium hydroxide. The preferred acids used in preparing the dispersions are dodecanoic (C.sub.12) and tridecanoic (C.sub.13).