# US 4,623,400 A · Hard surface coatings for metals in fluidized beds > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,623,400 A - Document ID: US4623400A - Status: Granted - Kind: A - Application number: 06/704,171 - Filed: 1985-02-22 - Granted: 1986-11-18 - Earliest claimed: 1985-02-22 - Assignees: Procedyne Corp. - Inventors: Joseph E. Japka; Robert Staffin; Swarnjeet S. Bhatia - Web page: https://patentgrep.com/patent/US4623400A ## CPC - C23C 16/442: using fluidised bed process - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) ## Abstract A process and apparatus for surface coating of workpieces in fluidized beds under atmospheric or slightly higher pressure is disclosed. The process comprises submerging the workpiece(s) in the fluidized bed, mixing a metal halide with an inert gas to form the fluidizing gas, feeding to the fluidized bed another gas which is capable of reacting with the metal halide in the fluidized bed and coating the workpiece(s). The workpiece(s) are maintained at a temperature in the range of from 1600.degree. F. to 2000.degree. F. until it is evenly coated. The apparatus comprises a saturator vessel for saturating the inert gas with the metal halide and a fluid bed reactor. There are several advantages that the present invention offers over the prior art, namely, the coating can be performed in a relatively short period of time, 4 to 5 hours and that atmospheric pressure can be used, eliminating the need for a costly vacuum system. ## Claims ### Claim 1 A process of surface coating a metal workpiece in a short period of time under substantially atmospheric pressure comprising: a. fluidizing a bed of inert particulate matter; b. submerging the workpiece in the fluidizied bed; c. heating the submerged workpiece in the fluidized bed to a predetermined temperature; d. fluidizing the bed with an inert gas in which a metal halide has been mixed; e. feeding a gas capable of forming a nitride, a sulfide, a carbide or an oxide with the metal of the metal halide and depositing the nitride, sulfide, carbide or oxide on the surface of the workpiece; f. maintaining the bed at the elevated temperature and slightly greater than atmospheric pressure for a period sufficient to coat the workpiece and provide a metallurgical bond between the coating and the workpiece; g. cooling the coated workpiece. ### Claim 2 (depends on 1) The process of claim 1 wherein the workpiece is heated to a temperature within the range of from 1000.degree. F. to 2200.degree. F. ### Claim 3 (depends on 1) The process of claim 1 wherein the metal halide is heated in a saturator and saturates the inert fluidizing gas within the range of 70.degree. F. to 200.degree. F. ### Claim 4 (depends on 3) The process of claim 3 wherein the inert gas mixed with the liquid metal halide in a saturator is argon gas. ### Claim 5 (depends on 3) The process of claim 3 wherein the inert gas mixed with the liquid metal halide in a saturator is nitrogen gas. ### Claim 6 (depends on 3) The process of claim 3 wherein the inert gas mixed with the liquid metal halide in a saturator is helium gas. ### Claim 7 (depends on 1) The process of claim 1 wherein the heated halide is mixed with an inert gas by direct introduction and evaporation into the inert gas stream using a metering device. ### Claim 8 (depends on 7) The process of claim 7 wherein the inert gas mixed with the metal halide by direct introduction is argon. ### Claim 9 (depends on 7) The process of claim 7 wherein the inert gas mixed with the metal halide by direct introduction is nitrogen. ### Claim 10 (depends on 7) The process of claim 7 wherein the inert gas mixed with the metal halide by direct introduction is helium. ### Claim 11 (depends on 1) The process of claim 1 wherein the gas capable of forming a nitride, a sulfide, a carbide or an oxide with the metal of the metal halide is fed in a stoicheometric ratio with the metal halide of from 18/1 to 90/1. ### Claim 12 (depends on 1) The process of claim 1 wherein the fluid bed reactor is heated by placing it into a fluid bed furnace. ### Claim 13 (depends on 1) The process of claim 1 wherein the fluid bed reactor is removed from the furnace and placed into a fluid bed quench bath for rapid cooling after coating has been complete. ### Claim 14 (depends on 1) The process of claim 1 wherein the plenum of the fluid bed reactor is operated at the same temperature as the furnace or the plenum is cooled below the temperature of the furnace. ### Claim 15 (depends on 1) The process of claim 1 wherein the halide of the metal is titanium tetrachloride. ### Claim 16 (depends on 1) The process of claim 1 wherein the inert fluidizing gas is argon gas. ### Claim 17 (depends on 1) The process of claim 1 wherein the gas capable of forming a nitride is ammonia. ### Claim 18 (depends on 1) The process of claim 1 wherein the gas capable of forming a carbide is methane. ### Claim 19 (depends on 1) The process of claim 1 wherein the gas capable of forming an oxide is air or oxygen. ### Claim 20 (depends on 1) The process of claim 1 wherein the reaction gas delivered into the reactor to form a nitride with the metal halide is nitrogen gas. ### Claim 21 (depends on 1) The process of claim 1 wherein the surface coating is achieved in 4 to 5 hours. ### Claim 22 (depends on 4, 15, 16) The process of claims 4, 15 or 16 wherein the surface coating is completed in 3 hours at 1800.degree. F. ### Claim 23 (depends on 22) The process of claim 22 wherein the surface coating is conducted under atmospheric or slightly higher pressure in the presence of argon. ### Claim 24 A process of surface coating a metal workpiece in a short period of time under substantially atmospheric pressure comprising: a. fluidizing a bed of inert particulate matter; b. submerging the workpiece in the fluidized bed; c. heating the submerged workpiece in the fluidized bed to a predetermined temperature; d. fluidizing the bed with an inert gas in which a metal halide has been mixed; e. feeding a gas capable of forming a nitride, a carbide or an oxide with the metal of the metal halide and depositing the nitride, carbide or oxide on the surface of the workpiece to provide a metallurgical bond between the coating and the workpiece. ### Claim 25 (depends on 1) The process of claim 1 wherein the step of cooling the coated workpiece comprises cooling the fluidized bed and the workpiece and removing the coated workpiece. ### Claim 26 (depends on 1) The process of claim 1 wherein the step of cooling the coated workpiece comprises removing the coated workpieces from the hot fluidized bed a cooling chamber for rapid cool down.