High density thermal spray coating and process

• US 5,019,429 A
• Filed: 08/11/1989
• Issued: 05/28/1991
• Est. Priority Date: 12/28/1987
• Status: Expired due to Fees

• Current Assignee: Thermal Spray Limited
• Original Assignee: Amoco Corporation (BP PLC)
• Inventors: Lindley, Donald J., Moskowitz, Larry N.
• Primary Examiner(s): Beck, Shrive
• Application Number:
  US07/392,451
• Time in Patent Office: 655 Days
• Field of Search: 427/422, 427/423
• US Class Current: 427/422
• CPC Class Codes: B05B 7/205 the material to be sprayed being originally a particulate material
• CPC Class Codes: C23C 4/129 Flame spraying
• CPC Class Codes: Y10S 220/24 Tank trucks
• CPC Class Codes: Y10S 220/917 Corrosion resistant container
• CPC Class Codes: Y10T 428/12493 Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
• CPC Class Codes: Y10T 428/125 Deflectable by temperature change [e.g., thermostat element]
• CPC Class Codes: Y10T 428/12507 More than two components
• CPC Class Codes: Y10T 428/12514 One component Cu-based
• CPC Class Codes: Y10T 428/12521 Both components Fe-based with more than 10% Ni
• CPC Class Codes: Y10T 428/1355 Elemental metal containing [e.g., substrate, foil, film, coating, etc.]
• CPC Class Codes: Y10T 428/139 Open-ended, self-supporting conduit, cylinder, or tube-type article
• CPC Class Codes: Y10T 428/31678 Of metal

Abstract

A high density, substantially oxide-free metal layer is deposited by spray deposition on a substrate in an atmosphere containing ambient air having an oxygen content above about 0.1% by weight. This is accomplished by directing a supersonic-velocity jet stream of hot gases carrying metal particles at the substrate through an inert gas shroud. The layer is useful as a corrosion barrier and for repairing metal substrates.

Claims

1. A method of depositing a layer on a substrate in an atmosphere containing ambient air having an oxygen content above about 1,000 parts per million comprising directing a high velocity jet stream of hot gases carrying metal particles at said substrate through a shroud effective to maintain a helically flowing stream of inert gas substantially concentrically around the particle carrying jet stream so as to essentially isolate said particle carrying jet stream from said atmosphere, wherein the volume of voids and oxide inclusions in said layer represents less than about 1% of said layer'"'"'s volume, and oxide in said layer represents less than about 1% of the layer by weight.

2. The method of claim 1, wherein said metal particles comprise fine particles of a metal alloy selected from the group consisting of stainless steel, Stellite™

and Hastelloy™

metal alloys.

3. The method of claim 2, wherein said layer comprises a corrosion barrier effective to protect a less corrosion resistant substrate from erosion and corrosion.

4. The method of claim 3, wherein said substrate comprises the internal shell of a process vessel.

5. The method of claim 3, wherein said substrate comprises the internal wall of the end of a tubular member.

6. The method of claim 3, wherein said substrate comprises the internal shell of a tank car.

7. The method of claim 1, wherein said layer replaces material lost or removed from said substrate.

8. The method of claim 6, wherein said layer is effective to repair substrate that has been corroded or eroded.

9. The method of claim 6, wherein said layer is effective to repair substrate that has developed cracks.