Corrosion resistant buffer system for metal products

• US 6,080,334 A
• Filed: 09/24/1997
• Issued: 06/27/2000
• Est. Priority Date: 10/21/1994
• Status: Expired due to Fees

• Current Assignee: Elisha Holding LLC
• Original Assignee: Elisha Technologies Co., LLC
• Inventors: Heimann, Robert L., Dalton, William M., Webb, David R., McGowan, Nancy M.
• Primary Examiner(s): WU, SHEAN CHIU
• Application Number:
  US08/936,152
• Time in Patent Office: 1,007 Days
• Field of Search: 427/251, 427/255.4, 427/216, 427/422, 427/427, 427/445, 427/219, 427/397.8, 428/935, 428/938, 106/1.17, 106/14.21, 106/600, 106/635, 422/11, 422/18, 422/19, 252/389.3, 252/389.62, 252/389.61, 252/389.32, 252/389.52, 148/279
• US Class Current: 252/389.62
• CPC Class Codes: C09D 1/00 Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances
• CPC Class Codes: C09D 1/02 alkali metal silicates
• CPC Class Codes: C09D 5/08 Anti-corrosive paints
• CPC Class Codes: C23C 28/04 only coatings of inorganic non-metallic material
• CPC Class Codes: C23C 30/00 Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process C23C26/00, C23C28/00 take precedence
• CPC Class Codes: C23F 11/00 Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent adding inhibitors to mineral oil, fuels, or lubricants C10; adding inhibitors to pickling solutions C23G
• CPC Class Codes: D07B 1/144 for cables or cable components built-up from metal wires
• CPC Class Codes: E04C 5/015 Anti-corrosion coatings or treating compositions, e.g. containing waterglass or based on another metal coating of discrete reinforcing elements C04B20/10
• CPC Class Codes: F16D 2250/0038 Surface treatment
• CPC Class Codes: F16D 69/02 Composition of linings ; Methods of manufacturing
• CPC Class Codes: G06F 9/3808 for instruction reuse, e.g. trace cache, branch target cache
• CPC Class Codes: G06F 9/383 Operand prefetching cache prefetching G06F12/0862
• CPC Class Codes: G06F 9/3834 Maintaining memory consistency
• CPC Class Codes: G06F 9/3842 Speculative instruction execution

Abstract

A system is disclosed for inhibiting the corrosion of ferrous and other metals by passivating the metals. The system includes novel buffered compositions which may be applied to metal products, and novel combinations thereof with metals, for preventing or retarding corrosion, as well as methods for applying the buffered compositions to metal products, such that corrosion protection of the products is achieved. The methods include an in-situ application to existing structures with metal reinforcement as well as applications to metal products during manufacture. Generally, the compositions may be in various forms and comprise one or more layers, at least one of which includes a water repellent but water vapor permeable carrier component and one or more pH buffer components. The buffer is selected to produce a passivating pH at the surface of the metal. The compositions are environmentally friendly and are capable of replacing chromates which have been traditionally used with zinc and zinc alloys to inhibit corrosion of metals but which are potentially harmful to the environment.

Claims

1. A method for treating a metal surface comprising:

preparing a first composition comprising a combination of a carrier and at least nne silicate buffer,

contacting tho metal surface with the first composition,

contacting the contacted metal surface with a second composition comprising a metal chloride thereby forming an outer partially insolublc layer; and

,

recovering the treated metal surface.

3. The method claim 1 or 2 wherein the first composition comprises water or a water soluble carrier and said alkali silicate buffer comprises at least one of sodium silicate and potassium silicate.

4. The method of claim 1 wherein the second composition comprises at least one metal chloride.

6. The method of claim 1 or 2 wherein the carrier comprises water.

7. The method of claim 1 wherein said metal surface comprises steel elements and the method comprises:

spraying a stream of an aqueous dispersion of the first composition comprising said at least one buffer,

maintaining a temperature sufficient to vaporize at least a portion of the water from the aqueous dispersion,

contacting said elements with the dispersion in a manner sufficient to coat at least a portion of the element with said buffer;

recovering said coated elements; and

further coating said steel elements with at least one of metal chloride or metal silicate.

8. The method of claim 1 wherein said metal surface comprises at least one steel element selected from the group consisting of particles and fiber for use in friction brake members and the method comprises:

(a) passing a stream of gas up through a bed of said steel elements under conditions to elevate such steel elements into a contact zone above the bed;

(b) spraying a stream of an aqueous dispersion of the first composition comprising said at least one buffer into the contact zone in intimate contact with said elevated steel elements so as to deposit said buffer material on at least a portion of said steel elements;

(c) maintaining the temperature of the contact zone at a level sufficient to vaporize water from the buffer material;

(d) recovering said stccl elements with deposited buffer material from said zone; and

(e) covering said steel elements with a partially water insoluble film upon said deposited buffer material.

9. The method of claim 1 wherein said metal surface comprises steel elements for use in friction brake materials and the method further comprises:

contacting said steel elements with a vaporized aqueous dispersion of the first composition said at least one buffer at a temperature sufficient to vaporize water from said buffer material and deposit said buffer material on said steel elements;

venting said vaporized water from said zone;

recovering said elements with deposited buffer material from said zone, said buffer material being selected to provide in the presence of moisture a pH at which said steel elements arc naturally passive to corrosion; and

covering said elements with a partially water insoluble film comprising zinc.

2. A metlod for treating a particulate material comprising:

preparing a first composition comprising a combination of a carrier and at least one alkali silicate buffer,

contacting the particulate material with the first composition,

contacting the contacted particulate material with a second composition comprising a metal chloride thereby forming a metal silicate; and

,

recovering the treated particulate material.

5. The method of claim 2 or 4 wherein the metal chloride comprises zinc chloride.

10. A method for improving the corrosion resistance of a metal surface comprising:

applying a first composition comprising sodium silicate to a metal surface comprising at least one member selected from the group consisting of fibers and particles by spray drying thereby forming an inner layer upon the metal surface,

applying a second composition comprising zinc chloride upon the inner layer by spray drying,

forming an outer layer comprising zinc silicate; and

,

recovering a layered metal surface having improved corrosion resistance.