Patent ID: 6171649
Filing Date: 2001-01-09
Classification: B05D

Abstract:
A method for preparing an aluminum-alloy aircraft component, comprising the steps of:providing an irregularly shaped aluminum-alloy component precursor having an individual mass of from about 0.2 to about 0.9 g;providing a coating apparatus comprising by three vertically contiguous sections, an upper section constituting an expansion zone, an intermediate section having a first wall extending upwardly, and a lower section including a second wall tapered inwardly frustoconically as it extends downwardly and terminating in a bottom inlet for gas, said intermediate and lower sections constituting a fluidized-bed vessel, with said second wall having an interior wall surface being divided into an upper portion and a lower portion, said upper portion being defined in the area of vertical movement of a rotor disc, said upper portion widening frustoconically in an upward direction, and a substantially horizontal rotor disc having a substantially flat bottom and being arranged for vertical movement, said rotor disc arranged above said bottom inlet of said vessel and below the top of said lower section and in radial proximity with said upper portion of said interior wall surface of said lower section, an adjuster for adjusting the vertical height of the rotor disc, a rotor for rotating the rotor disc, a vacuum assembly positioned above and in fluid communication with the upper section for pulling a flow of gas into the vessel through the bottom inlet and through an annular gap around the periphery of the rotor disc so that the flow of gas follows the outwardly widening wall surface of the lower section, a valve for releasing material to be treated into the fluidized bed above the rotor disc to form a fluidized bed moved by the rotor disc and the flow of gas being pulled through the annular gap, a plurality of nozzles positioned below the expansion zone for introducing a coating into the fluidized-bed vessel, whereby the gas is released at an initial gas flow velocity and the velocity of the gas flow is adjusted to the mass, or density, particle size and surface area characteristics of the precursor by varying the height of the rotor disc in relation to the upper portion of the interior walls of the vessel to decrease the gap and increase the gas flow velocity and alternatively to increase the gap and decrease the gas flow velocity;introducing the component to the apparatus;directing a gas flow to the apparatus interior;introducing a corrosion resistant coating material to the apparatus interior;engaging the apparatus to an operable function; andcoating the precursor to achieve a substantially uniform coating thickness from about 0.00015 to about 0.0005 inch.