# US 5,706,999 A · Preparation of a coated metal-matrix composite material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,706,999 A - Document ID: US5706999A - Status: Granted - Kind: A - Application number: 08/563,710 - Filed: 1995-11-28 - Granted: 1998-01-13 - Earliest claimed: 1995-11-28 - Assignees: Hughes Electronics Corporation - Inventors: John K. Lim; Joseph S. Russo - Web page: https://patentgrep.com/patent/US5706999A ## CPC - C22C 32/0063: {based on SiC} - C23C 26/00: Coating not provided for in groups C23C2/00 - C23C24/00 - C22C 2204/00: End product comprising different layers, coatings or parts of cermet - Y10S 205/917: Treatment of workpiece between coating steps - C22C: ALLOYS (treatment of alloys C21D, C22F) - 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) - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract A composite material of silicon carbide particles in an aluminum matrix is base coated with a layer of a nickel-boron alloy by an electroless process. The base-coated composite material is heat treated at a temperature of about 450.degree. C. to interdiffuse the base coating with the composite material. A nickel or gold top layer is electrolytically deposited over the base coat on the heat-treated composite material. ## Claims ### Claim 1 A method for preparing a coated metal-matrix composite material, comprising the steps of: furnishing a piece of a composite material having an aluminum matrix and reinforcement particles dispersed therein; depositing a metallic base coating having a first composition onto at least a portion of the piece of composite material to form a base-coated composite material; thereafter heating the base-coated composite material to a temperature and for a time sufficient to cause the base coating to interdiffuse into the piece of composite material, forming a heat-treated composite material; and depositing a metallic top coating having a second composition directly onto the base coating on the heat-treated composite material. ### Claim 2 (depends on 1) The method of claim 1, wherein the step of furnishing includes the step of furnishing a piece of a composite material having an aluminum matrix and silicon carbide particles dispersed therein. ### Claim 3 (depends on 1) The method of claim 1, wherein the step of depositing a metallic base coating includes the step of depositing a metallic base coating by an electroless process. ### Claim 4 (depends on 1) The method of claim 1, wherein the step of depositing a metallic base coating includes the step of depositing a nickel-boron coating. ### Claim 5 (depends on 1) The method of claim 1, wherein the step of depositing a metallic base coating includes the step of depositing a metallic base coating of from about 150 to about 250 microinches thick. ### Claim 6 (depends on 1) The method of claim 1, wherein the step of heating includes the step of heating the base-coated composite material to a temperature of from about 425.degree. C. to about 475.degree. C. ### Claim 7 (depends on 1) The method of claim 1, wherein the step of heating includes the step of heating the base-coated composite material to a temperature of about 450.degree. C. for a time of about 15 hours. ### Claim 8 (depends on 1) The method of claim 1, wherein the step of depositing a metallic top coating includes the step of depositing a top coating of a metal selected from the group of nickel and gold. ### Claim 9 (depends on 1) The method of claim 1, wherein the step of depositing a metallic top coating includes the step of depositing a top coating by an electrolytic process. ### Claim 10 (depends on 1) The method of claim 1, including an additional step, after the step of depositing a metallic top coating, of affixing an electronic device to the top coating. ### Claim 11 (depends on 10) The method of claim 10, wherein the step of affixing includes the step of affixing the electronic device to the top coating by a method selected from the group consisting of brazing and soldering. ### Claim 12 A method for preparing a coated metal-matrix composite material, comprising the steps of: furnishing a piece of a composite material having an aluminum matrix and silicon carbide reinforcement particles dispersed therein; depositing by an electroless process a metallic base coating having a first composition onto at least a portion of the piece of composite material to form a base-coated composite material; heating the base-coated composite material to a temperature of from about 440.degree. C. to about 460.degree. C. for a time of from about 14 hours to about 16 hours; and depositing by an electrolytic process a metallic top coating having a second composition directly onto the base coating on the heat-treated composite material. ### Claim 13 (depends on 12) The method of claim 12, wherein the step of depositing a metallic base coating includes the step of depositing a nickel-boron coating. ### Claim 14 (depends on 12) The method of claim 12, wherein the step of depositing a metallic base coating includes the step of depositing a metallic base coating of from about 150 microinches to about 250 microinches thick. ### Claim 15 (depends on 12) The method of claim 12, wherein the step of heating includes the step of heating the base-coated composite material in a high-purity, low-moisture nitrogen atmosphere. ### Claim 16 (depends on 12) The method of claim 12, wherein the step of depositing a metallic top coating includes the step of depositing a top coating of a metal selected from the group of nickel and gold. ### Claim 17 A method for preparing a coated metal-matrix composite material, comprising the steps of: furnishing a piece of a composite material having an aluminum matrix and silicon carbide reinforcement particles dispersed therein; depositing by an electroless process a nickel-boron metallic base coating onto at least a portion of the piece of composite material to form a base-coated composite material; heating the base-coated composite material in nitrogen gas to a temperature of from about 440.degree. C. to about 460.degree. C. for a time of from about 14 hours to about 16 hours; and depositing by an electrolytic process a metallic top coating having a second composition directly onto the base coating on the heat-treated composite material, the top coating having a composition selected from the group consisting of a nickel alloy and a gold alloy.