Method of forming a coating

Abstract

A method is provided of forming a coating within an internal pathway. The method comprises: providing a body having an inlet and an outlet and an internal surface which defines an internal pathway extending within the body between the inlet and the outlet; streaming a mixture of a gas and a fluid along at least a part of a length of the internal pathway, the fluid comprising one or more substances for forming a solid coating on the internal surface, the fluid being a liquid solution of said one or more substances in a solvent or being a dispersion with at least one of said one or more substances being solid particles dispersed in a liquid continuous phase; during said streaming of the mixture, applying localised heat progressively along said at least a part of the length of the internal pathway. The progressive application of localised heat causes, within said at least a part of the length of the internal pathway, formation from the one or more substances of a solid coating on the internal surface.

1 . A method of forming a coating within an internal pathway, comprising:
 providing a body having an inlet and an outlet and an internal surface which defines an internal pathway extending within the body between the inlet and the outlet;   streaming a mixture of a gas and a fluid along at least a part of a length of the internal pathway, the fluid comprising one or more substances for forming a solid coating on the internal surface, the fluid being a liquid solution of said one or more substances in a solvent or being a dispersion with at least one of said one or more substances being solid particles dispersed in a liquid continuous phase;   during said streaming of the mixture, applying localised heat progressively along said at least a part of the length of the internal pathway;   wherein said progressive application of localised heat causes, within said at least a part of the length of the internal pathway, formation from the one or more substances of a solid coating on the internal surface; and   wherein the body is formed from a material selected from the group consisting of: silica, steel, titanium, aluminium, and plastics.   
     
     
         2 - 4 . (canceled) 
     
     
         5 . A method according to  claim 1 , wherein the body is porous and the internal pathway is formed by a plurality of interconnecting internal spaces within the body and defined by the internal surface. 
     
     
         6 . A method according to  claim 5 , wherein the body includes an impermeable portion which defines a perimeter of the internal pathway between the inlet and the outlet. 
     
     
         7 . A method according to  claim 1 , wherein the body is elongate having a length and an external surface extending along the body length, wherein said at least a part of the length of the internal pathway is co-extensive with at least a part of the length of the body, wherein said progressive application of localised heat along the internal pathway comprises application of localised heat to the external surface of the body progressively along said at least a part of the length of the body. 
     
     
         8 . A method according to  claim 7 , wherein the localised application of heat to the external surface of the body is applied by a heater which surrounds a portion of the length of the body so that heat is applied to the external surface of the body all around the portion, and wherein there is progressive relative movement between the body and the heater so that successive portions of the length of the body are surrounded by and heated by the heater. 
     
     
         9 - 10 . (canceled) 
     
     
         11 . A method according to  claim 1 , wherein the one or more substances comprise a solute in the solvent or in the liquid continuous phase, the solute undergoing thermal decomposition to form a decomposition product during said localised heating, the coating comprising the decomposition product. 
     
     
         12 . A method according to  claim 11 , wherein the solute comprises a metallic cation, and wherein the decomposition product is a metal oxide. 
     
     
         13 . A method according to  claim 12 , wherein the metallic cation is selected from the group consisting of: titanium, zinc, aluminium, magnesium, calcium, scandium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, gallium, germanium, strontium, yttrium, niobium, molybdenum, ruthenium, rhodium, palladium, silver, cadmium, indium, tin, antimony, tellurium, barium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, mercury, thallium, lead, bismuth, zirconium, and lanthanum or actinium group metals. 
     
     
         14 . A method according to  claim 13 , wherein the metal oxide is a porous solid and the metallic cation is selected from the group consisting of: titanium, zinc, aluminium, magnesium, calcium, scandium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, gallium, germanium, strontium, yttrium, niobium, molybdenum, cadmium, indium, tin, antimony, tellurium, barium, tantalum, tungsten, thallium, lead, bismuth, zirconium, and lanthanum or actinium group metals. 
     
     
         15 . A method according to  claim 12 , wherein the solute comprises an anion or a ligand, and wherein the anion or the ligand is selected from the group consisting of: nitrate, acetate, acetyl acetonate, nitrite, chloride, citrate, ammonia, carbonyl, cyclopentadienyl and its derivatives, and anions of organic acids including amino acids. 
     
     
         16 . A method according to  claim 1 , wherein said fluid is said dispersion, the coating comprising the solid particles. 
     
     
         17 . A method according to  claim 16 , wherein the solid particles are selected from, or independently selected from when there are solid particles of more than one said substances, the group consisting of: silicon dioxide, aluminium oxide, titanium dioxide, cerium oxide, zirconium oxide, iron oxide, carbon, mixed oxides, or combinations thereof. 
     
     
         18 . (canceled) 
     
     
         19 . A method according to  claim 1 , wherein after said formation of the coating, the body is heated to stabilise the coating. 
     
     
         20 . A method according to  claim 1 , wherein the coating is porous and wherein after the formation of the coating, the coating is impregnated with metal particles. 
     
     
         21 . A method according to  claim 20 , wherein the metal particles are selected from the group consisting of particles of: platinum, palladium, rhodium, osmium, iridium, ruthenium, copper, silver, cobalt, iron, nickel and gold. 
     
     
         22 . A method according to  claim 20 , wherein said impregnation comprises filing said at least part of the length of the internal pathway with a suspension of the metal particles in a liquid and evaporating the liquid. 
     
     
         23 . A method according to  claim 20 , wherein the impregnation comprises filing said at least part of the length of the internal pathway with a solution comprising a solute comprising metal cations, and heating the solution to cause decomposition of the solute so that the metal cations form the metal particles. 
     
     
         24 . (canceled) 
     
     
         25 . A method according to  claim 20 , wherein after said formation of said coating and before said impregnation of the coating with the metal particles, the body is heated to stabilise the coating. 
     
     
         26 . A method according to  claim 1 , wherein the coating comprises a porous component and metal particles entrapped in the porous component. 
     
     
         27 - 30 . (canceled) 
     
     
         31 . A method according to  claim 1 , wherein the coating is porous and wherein the fluid comprises a molecule in solution which acts to increase the mean pore diameter in the coating. 
     
     
         32 - 38 . (canceled)