Patent ID: 6645778
Filing Date: 2003-11-11
Classification: A61L,B01D,C23C,Y02A,Y10S

Abstract:
A method for preparing a ferroelectric semiconductive coating, comprising the steps of:(a) mixing tetraethyl orthotitanate with a water/alkoxide mixture in a molar ratio of between 10-50 to form a mixture, stirring the mixture for about 2-8 hours to decompose the mixture, and adding a water solution of 1 to 7 wt. % hydrochloric acid or sulfuric acid to the decomposed mixture to form titanic acid oxide; (b) mixing the titanic acid oxide produced in step (a) with a methanol solution, adding an oxygen producing activating agent containing about 0.1-0.7 mole % manganese in 12.5 wt. % manganese chloride water solution, about 1.5-3.5 mole % bismuth in 7 wt. % bismuth chloride water solution, about 0.5-1.5 mole % nickel in 11.7 wt. % nickel chloride water solution and about 5-8 wt. % strontium, where the mole %'s in the oxygen producing activating agent are on the basis of titanium oxide as 100 mole %; (c) adding to the product of step (b) a hydrocarbon adsorption activating agent containing about 0.1-0.5 mole % of 0.5 wt. % platinum chloride water solution, about 2-10 mole % of 0.5 wt. % silver chloride dissolved in 10% aqueous ammonia, about 0.5-15.0 mole % of 5 wt. % tungsten trioxide dissolved in 7.5 wt. % aqueous lithium hydroxide and about 1-15 mole % of 5 wt. % molybdenum oxide and mixing the product of step (b) with the hydrocarbon adsorption activating agent to form a coating material, wherein intercalation of the lithium ion substantially improves the electric conductivity of the coating material and moves a conduction band of said coating material to a positive value; (d) adding about 1-5 mole % of an oxidation type of cobalt oxide having an oxygen carrier function to the product of step (c), thereby adjusting the energy band gap of the titanium oxide; (e) dispersing sufficient product from step (d) on a metal to produce a coating on said metal having a thickness of about 15-30 micrometers after drying; and (f) heating the coating for about 6-12 hours at a temperature of about 400-600Â° C., thereby producing the ferroelectric semiconductive coating.