Multilayered chromium oxide bonded, hardened and densified coatings and method of making same

Claim 1

A method of producing a multiple layered relatively thick chemically hardened refractory coating on a substrate at least the surface of which is a refractory oxide having a vitrification temperature in excess of 600° F. which comprises: (a) applying an initial coating layer to the substrate comprised of a slurry of a finely divided, particulate refractory material at least the surface of which is a refractory oxide and a solution of a suitable inorganic binder which is capable of being converted to an oxide on being heated; (b) drying and curing said applied coating by heating same to a temperature below the vitrification temperature of the refractory material but sufficient to convert the binder in situ to an oxide to harden and densify the coating; (c) impregnating the initial hardened coating with a solution containing an effective amount of a chromium compound which is capable of being converted to a water insoluble oxide on being heated and characterized by: (d) applying, to the impregnated coating, a second coating layer of a slurry of a finely divided particulate refreactory material at least the surface of which is a refractory oxide and a solution of a suitable inorganic binder which is capable of being converted to a water insoluble oxide on being heated; (e) drying and curing the slurry coating by heating same to a temperature below the vitrification temperature of the refractory oxide but sufficient to convert the chromium compound in situ to a water insoluble oxide; and, (f) repeating the impregnation step (c) before coating, then coating (d) and curing (e) and repeating the impregnating (c), coating (d) and curing (e) steps unitl a desired thickness multiple layered coating is achieved.

Claim 2

A method of producing a multiple layered relatively thick chemically hardened refractory coating on a substrate at least the surface of which is a refractory oxide having a vitrification temperature in excess of 600° F. which comprises: (a) applying an initial coating layer to the substrate comprised of a slurry of a finely divided, particulate refractory material at least the surface of which is a refractory oxide and a solution of a suitable inorganic binder which is capable of being converted to an oxide on being heated; (b) drying and curing said applied coating by heating same to a temperature below the vitrification temperature of the refractory material but sufficient to convert the binder in situ to an oxide to harden and densify the coating; (c) impregnating the initial hardened coating with a solution containing an effective amount of a chromium compound which is capable of being converted to a water insoluble oxide on being heated and characterized by: (d) applying, to the impregnated coating, a second coating layer of a slurry of a finely divided particulate refreactory material at least the surface of which is a refractory oxide and a solution of a suitable inorganic binder which is capable of being converted to a water insoluble oxide on being heated; (e) drying and curing the slurry coating by heating same to a temperature below the vitrification temperature of the refractory oxide but sufficient to convert the chromium compound in situ to a water insoluble oxide; and, (f) repeating the impregnation step (c) before coating, then coating (d) and curing (e) and repeating the impregnating (c), coating (d) and curing (e) steps unitl a desired thickness multiple layered coating is achieved.

Claim 9

A method of producing a multiple layered relatively thick chemically hardened refractory coating on a substrate at least the surface of which is a refractory oxide having a vitrification temperature in excess of 600° F. which comprises: (a) applying an initial coating layer to the substrate comprised of a slurry of a finely divided, particulate refractory material at least the surface of which is a refractory oxide and a solution of a suitable inorganic binder which is capable of being converted to an oxide on being heated; (b) drying and curing said applied coating by heating same to a temperature below the vitrification temperature of the refractory material but sufficient to convert the binder in situ to an oxide to harden and densify the coating; (c) impregnating the initial hardened coating with a solution containing an effective amount of a chromium compound which is capable of being converted to an oxide on being heated; (d) applying a second coating layer of refractory material at least the surface of which is a refractory oxide and a water slurry to the impregnated coating on the substrate; (e) drying and curing the slurry coating by heating same to a temperature below the vitrification temperature of the refractory oxide but sufficient to convert the chromium compound in situ to an oxide; and, (f) repeating the impregnation step (c) before coating, then coating (d) and curing (e) and repeating the impregnating (c), coating (d) and curing (e) steps until a desired thickness multiple layered coating is achieved.

Claim 10

A method of producing a multiple layered relatively thick chemically hardened refractory coating on a substrate at least the surface of which is a refractory oxide having a vitrification temperature in excess of 600° F. which comprises: (a) applying an initial coating layer to the substrate comprised of a slurry of a finely divided, particulate refractory material at least the surface of which is a refractory oxide and a solution of a suitable inorganic binder which is capable of being converted to an oxide on being heated; (b) drying and curing said applied coating by heating same to a temperature below the vitrification temperature of the refractory material but sufficient to convert the binder in situ to an oxide to harden and densify the coating; (c) impregnating the initial hardened coating with a solution containing an effective amount of a chromium compound which is capable of being converted to an oxide on being heated; (d) applying a second coating layer of refractory material at least the surface of which is a refractory oxide and a water slurry to the impregnated coating on the substrate; (e) drying and curing the slurry coating by heating same to a temperature below the vitrification temperature of the refractory oxide but sufficient to convert the chromium compound in situ to an oxide; and, (f) repeating the impregnation step (c) before coating, then coating (d) and curing (e) and repeating the impregnating (c), coating (d) and curing (e) steps until a desired thickness multiple layered coating is achieved.

Claim 17

A method of producing a multiple layered relatively thick chemically hardened refractory coating on a substrate at least the surface of which is a refractory oxide having a vitrification temperature in excess of 600° F. which comprises: (a) applying an initial coating layer to the substrate comprised of a slurry of a finely divided, particulate refractory material at least the surface of which is a refractory oxide and a solution of a suitable inorganic binder which is capable of being converted to an oxide on being heated; (b) drying and curing said applied coating by heating same to a temperature below the vitrification temperature of the refractory material but sufficient to convert the binder in situ to an oxide to harden and densify the coating; (c) impregnating the initial hardened coating with water; (d) applying a second coating layer of particulate refractory material at least the surface of which is a refractory oxide and a solution containing an effective amount of a chromium compound as a slurry to the water impregnated coating on the substrate; (e) drying and curing the slurry coating by heating same to a temperature below the vitrification temperature of the refractory oxide but sufficient to convert the chromium compound in situ to a water insoluble oxide; and, (f) repeating the impregnation step (c) before coating, then coating (d) and curing (e) and repeating the impregnating (c), coating (d) and curing (e) steps until a desired thickness multiple layered coating is achieved.

Claim 18

A method of producing a multiple layered relatively thick chemically hardened refractory coating on a substrate at least the surface of which is a refractory oxide having a vitrification temperature in excess of 600° F. which comprises: (a) applying an initial coating layer to the substrate comprised of a slurry of a finely divided, particulate refractory material at least the surface of which is a refractory oxide and a solution of a suitable inorganic binder which is capable of being converted to an oxide on being heated; (b) drying and curing said applied coating by heating same to a temperature below the vitrification temperature of the refractory material but sufficient to convert the binder in situ to an oxide to harden and densify the coating; (c) impregnating the initial hardened coating with water; (d) applying a second coating layer of particulate refractory material at least the surface of which is a refractory oxide and a solution containing an effective amount of a chromium compound as a slurry to the water impregnated coating on the substrate; (e) drying and curing the slurry coating by heating same to a temperature below the vitrification temperature of the refractory oxide but sufficient to convert the chromium compound in situ to a water insoluble oxide; and, (f) repeating the impregnation step (c) before coating, then coating (d) and curing (e) and repeating the impregnating (c), coating (d) and curing (e) steps until a desired thickness multiple layered coating is achieved.

Claim 28

A method of producing a multiple layered chemically hardened refractory coating on a substrate at least the surface of which is a refractory oxide having a vitrification temperature in excess of 600° F. which comprises: (a) applying an initial coating layer to the substrate comprised of a slurry of finely divided, particulate refractory material at least the suface of which is a refractory oxide and a solution of a suitable inorganic binder which is capable of being converted to a water insoluble oxide on being heated; (b) drying and curing said applied coating by heating same to a temperature below the vitrification temperature of the refractory material but sufficient to convert the binder in situ to an oxide to harden and densify the coating; (c) impregnating the initial hardened coating with a liquid comprising water; and characterized by: (d) applying, to the impregnated coating on the substrate, a second coating layer of a slurry of a finely divided, particulate refractory material, at least the surface of which is a refractory oxide, and a solution of a suitable inorganic binder which is capable of being converted to a water insoluble oxide on being heated; (e) drying and curing the slurry coating by heating same to a temperature below the vitrification temperature of the refractory oxide but sufficient to convert the binder in situ to a water insoluble oxide; and, (f) repeating an impregnation-coating-curing cycle comprising, in sequence, the impregnation step (c), the coating step (d) and the curing step (f), until a multiple layered coating of a desired thickness is achieved.

Claim 29

A method of producing a multiple layered chemically hardened refractory coating on a substrate at least the surface of which is a refractory oxide having a vitrification temperature in excess of 600° F. which comprises: (a) applying an initial coating layer to the substrate comprised of a slurry of finely divided, particulate refractory material at least the suface of which is a refractory oxide and a solution of a suitable inorganic binder which is capable of being converted to a water insoluble oxide on being heated; (b) drying and curing said applied coating by heating same to a temperature below the vitrification temperature of the refractory material but sufficient to convert the binder in situ to an oxide to harden and densify the coating; (c) impregnating the initial hardened coating with a liquid comprising water; and characterized by: (d) applying, to the impregnated coating on the substrate, a second coating layer of a slurry of a finely divided, particulate refractory material, at least the surface of which is a refractory oxide, and a solution of a suitable inorganic binder which is capable of being converted to a water insoluble oxide on being heated; (e) drying and curing the slurry coating by heating same to a temperature below the vitrification temperature of the refractory oxide but sufficient to convert the binder in situ to a water insoluble oxide; and, (f) repeating an impregnation-coating-curing cycle comprising, in sequence, the impregnation step (c), the coating step (d) and the curing step (f), until a multiple layered coating of a desired thickness is achieved.

Claim 32

A method of producing a multiple layered chemically hardened refractory coating on a substrate at least the surface of which is a refractory oxide having a vitrification temperature in excess of 600° F., which comprises: (a) applying an initial coating layer to the substrate comprised of a water based slurry of a finely divided, particulate refractory material at least the surface of which is a refractory oxide; (b) drying and curing said applied coating by heating same to a temperature below the vitrification temperature of the refractory material; (c) impregnating the initial coating with a solution containing a soluble chromium compound binder which is capable of being converted to a water insoluble oxide on being heated; and characterized by: (d) applying, to the impregnated coating on the substrate, a second coating layer of a water based slurry of a finely divided particulate refractory material at lest the surface of which is a refractory oxide; (e) drying and curing the slurry coating by heating same to a temperature below the vitrification temperature of the refractory oxide but sufficient to convert the chromium compound binder to a water insoluble oxide; and, (f) repeating an impregnation-coating-curing cycle comprising, in sequence, the impregnation step (c), the coating step (d) and the curing step (e), until a multiple layered coating of a desired thickness is achieved.

Claim 33

A method of producing a multiple layered chemically hardened refractory coating on a substrate at least the surface of which is a refractory oxide having a vitrification temperature in excess of 600° F., which comprises: (a) applying an initial coating layer to the substrate comprised of a water based slurry of a finely divided, particulate refractory material at least the surface of which is a refractory oxide; (b) drying and curing said applied coating by heating same to a temperature below the vitrification temperature of the refractory material; (c) impregnating the initial coating with a solution containing a soluble chromium compound binder which is capable of being converted to a water insoluble oxide on being heated; and characterized by: (d) applying, to the impregnated coating on the substrate, a second coating layer of a water based slurry of a finely divided particulate refractory material at lest the surface of which is a refractory oxide; (e) drying and curing the slurry coating by heating same to a temperature below the vitrification temperature of the refractory oxide but sufficient to convert the chromium compound binder to a water insoluble oxide; and, (f) repeating an impregnation-coating-curing cycle comprising, in sequence, the impregnation step (c), the coating step (d) and the curing step (e), until a multiple layered coating of a desired thickness is achieved.

Claim 38

A method of producing a multiple layered relatively thick chemically hardened refractory coating on a substrate at least the surface of which is a refractory oxide having a vitrification temperature in excess of 600° F. which comprises: (a) applying an initial coating layer to the substrate comprised of a slurry of a finely divided, particulate refractory material at least the surface of which is a refractory oxide and a solution of a suitable inorganic binder which is capable of being converted to an oxide on being heated; (b) drying and curing said applied coating by heating same to a temperature below the vitrification temperature of the refractory material but sufficient to convert the binder in situ to an oxide to harden and densify the coating; (c) impregnating the initial hardened coating with a liquid comprising water; and characterized by: (d) applying, to the impregnated coating, a second coating layer of a slurry of a finely divided particulate refractory material at least the surface of which is a refractory oxide and a solution of a suitable inorganic binder which is capable of being converted to a water insoluble oxide on being heated; (e) drying and curing the slurry coating by heating same to a temperature below the vitrification temperature of the refractory oxide but sufficient to convert the chromium compound in situ to a water insoluble oxide; and, (f) repeating the impregnation step (c) before coating, then coating (d) and curing (e) and repeating the impregnating (c), coating (d) and curing (e) steps unitil a desired thickness multiple layered coating is achieved.

Claim 39

A method of producing a multiple layered relatively thick chemically hardened refractory coating on a substrate at least the surface of which is a refractory oxide having a vitrification temperature in excess of 600° F. which comprises: (a) applying an initial coating layer to the substrate comprised of a slurry of a finely divided, particulate refractory material at least the surface of which is a refractory oxide and a solution of a suitable inorganic binder which is capable of being converted to an oxide on being heated; (b) drying and curing said applied coating by heating same to a temperature below the vitrification temperature of the refractory material but sufficient to convert the binder in situ to an oxide to harden and densify the coating; (c) impregnating the initial hardened coating with a liquid comprising water; and characterized by: (d) applying, to the impregnated coating, a second coating layer of a slurry of a finely divided particulate refractory material at least the surface of which is a refractory oxide and a solution of a suitable inorganic binder which is capable of being converted to a water insoluble oxide on being heated; (e) drying and curing the slurry coating by heating same to a temperature below the vitrification temperature of the refractory oxide but sufficient to convert the chromium compound in situ to a water insoluble oxide; and, (f) repeating the impregnation step (c) before coating, then coating (d) and curing (e) and repeating the impregnating (c), coating (d) and curing (e) steps unitil a desired thickness multiple layered coating is achieved.