Apparatus and method for sealing anodized aluminum parts

Abstract

An apparatus for sealing an anodized aluminum oxide film includes a container with an airtight cover. The container has a sidewall and a bottom. A level sensor and a pressure gauge are mounted to the sidewall interior. The level sensor sends an alarm signal to shut off the heater if a liquid level falls below a predetermined value. The pressure gauge monitors pressure within the container. A heater is mounted in the bottom. A method of sealing an anodized aluminum oxide film with a thick and nonporous boehmite layer includes filling the apparatus with a sealing solution to a predetermined level; immersing the parts into the sealing solution; sealing the container with the cover; and heating the apparatus achieve a pressure of about 10 psi or higher, while maintaining the sealing solution in a liquid phase around the parts.

What is claimed is: 
     
         1 . An apparatus operative to seal an anodized aluminum oxide film with a thick and nonporous boehmite layer, comprising:
 (a) a container having a sidewall and a bottom, with
 (i) a heater mounted in the bottom; 
 (ii) a level sensor mounted to an interior of the sidewall, operative to send an alarm signal to shut off the heater if a liquid level falls below a predetermined value; and 
 (iii) a pressure gauge mounted at an inner top of the sidewall, operative to monitor pressure within the container; and 
   (b) an airtight cover.   
     
     
         2 . The apparatus of  claim 1 , further comprising a controller having an adjustable timer setting and an adjustable cycle setting, mounted on an outside surface of the sidewall, wherein the controller is operative to control the heater. 
     
     
         3 . The apparatus of  claim 1 , further comprising a removable rack operative to suspend anodized aluminum parts within the container mounted to the interior of the sidewall. 
     
     
         4 . The apparatus of  claim 1 , wherein the container and the airtight cover are formed of stainless steel. 
     
     
         5 . A method of sealing an anodized aluminum oxide film with a thick and nonporous boehmite layer, comprising:
 (a) providing the apparatus of  claim 1 ;   (b) filling the apparatus with a sealing solution to a predetermined level;   (c) immersing the anodized aluminum parts into the sealing solution;   (d) sealing the container with the airtight cover; and   (e) heating the apparatus to a temperature associated with a pressure of at least about 10 psi; maintaining the temperature and pressure for a period of time while maintaining the sealing solution in a liquid phase around the anodized aluminum parts.   
     
     
         6 . The method of  claim 5 , wherein the sealing solution is an aqueous nickel solution or water. 
     
     
         7 . The method of  claim 5 , returning the interior of the container to about 1 atmosphere pressure and removing the anodized aluminum parts. 
     
     
         8 . The method of  claim 5 , wherein the heater maintains a temperature inside the container of at least about 110° C. 
     
     
         9 . The method of  claim 5 , wherein the period of time is about 1 to about 2 hours. 
     
     
         10 . The method of  claim 5 , wherein the period of time comprises a first period of time with the heater at a first heat setting until a preset steam pressure is reached; and second period of time with the heater at a second heat setting lower than the first heat setting. 
     
     
         11 . The method of  claim 10 , wherein if the pressure falls below the preset steam pressure, operating the heater at the first heat setting to recover the preset steam pressure.