Patent ID: 6228424
Filing Date: 2001-05-08
Classification: B05C,C04B,C25C

Abstract:
A method of treating an open-pored porous body (11) which is to be exposed to oxidising conditions or other chemical attack at high temperatures so as to protect the body against oxidation or chemical attack at said high temperatures, which method comprises:A) bringing into contact with the surface of the body (11) at a temperature which is about or just above ambient temperature a hot treating liquid (10) containing a dissolved treating agent at a concentration below saturation concentration, the hot treating liquid being at a temperature above the temperature of the body and the concentration of treating agent in the hot treating liquid being such that when the liquid is cooled down to the temperature of the body, the liquid saturates and the treating agent precipitates;B) applying a pressure differential to cause the treating liquid to impregnate into the surface pores of the body and deposit, within pores of the body (11) underneath the surface, a layer of the treating agent precipitated from the liquid inside the body by cooling as the liquid impregnates the pores of the body, andC) controlling said bringing into contact of the surface of the body (11) with the treating liquid (10) and applying said pressure differential so that the temperature of the body remains below the temperature of the treating liquid during the entire duration of their contact;said precipitated layer of the treating agent inside the body forming, when the body is exposed to said high temperatures, a protective layer in the surface pores which protects the body against oxidation or other chemical attack.