# US 7,744,775 B2 · Heat transfer fluid compositions for cooling systems containing magnesium or magnesium alloys

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- Number: US 7,744,775 B2
- Document ID: US7744775B2
- Status: Granted
- Kind: B2
- Application number: 12/620,211
- Filed: 2009-11-17
- Published: 2010-03-11
- Granted: 2010-06-29
- Earliest claimed: 2005-10-25
- Assignees: Honeywell International Inc.
- Inventors: Bo Yang; Filipe J. Marinho
- Web page: https://patentgrep.com/patent/US7744775B2

## CPC

- C23F 11/08: in other liquids
- C09K 5/20: Antifreeze additives therefor, e.g. for radiator liquids (for application to surfaces C09K3/18; inhibiting corrosion by liquids C23F11/00)
- C23F 11/10: using organic inhibitors
- C23F 11/124: {Carboxylic acids}
- C23F 11/188: {containing phosphates}
- F28F 19/00: Preventing the formation of deposits or corrosion, e.g. by using filters {or scrapers}
- C23F: NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE (working metal by laser beams B23K26/00; desurfacing by applying flames B23K7/00; working of metal by electro-erosion B23H; producing decorative effects by removing surface material, e.g. by engraving, by etching, B44C1/22; electrolytic etching or polishing C25F); INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16)

## Abstract

In one embodiment, a corrosion inhibiting composition is formed by combining: (a) an inorganic phosphate; (b) a water soluble polyelectrolyte polymer dispersant; (c) a tri or tetracarboxylic acid; and (d) at least one additional component comprising at least one of a C4-C22 aliphatic or aromatic mono- or dicarboxylic acid, a silicate and at least one of a silicone or a silicate stabilizing siloxane compound, and mixtures thereof. Also disclosed are heat transfer fluids that include about 5% to about 99% by weight of freezing point-depressing agent; about 1% to about 95% by weight of water; and the disclosed corrosion inhibitor composition. A method of reducing corrosion in a heat transfer system containing one or more components that contain magnesium or a magnesium alloy requires that the system and the magnesium containing components be in contact with the disclosed heat transfer fluid.

## Claims

### Claim 1

A heat transfer system comprising
at least one component comprising magnesium or a magnesium alloy and a heat transfer fluid comprising
about 5% to about 99% by weight of freezing point-depressing agent;
about 1% to about 95% by weight of water; and
a corrosion inhibiting composition formed by combining components comprising:
(a) an inorganic phosphate;
(b) a water soluble polyelectrolyte polymer dispersant; and
(d) at least one additional component comprising at least one of a C4-C22 aliphatic or aromatic mono- or dicarboxylic acid, a silicate and at least one of a silicone or a silicate stabilizing siloxane compound, and mixtures thereof.

### Claim 2 (depends on 1)

The heat transfer system of claim 1 wherein the heat transfer fluid further comprises c) an aliphatic tri or tetracarboxylic acid.

### Claim 3 (depends on 1)

The heat transfer system of claim 1 wherein component (d) further comprises one or more members selected from the group consisting of a C4-C22 aliphatic or aromatic mono- or dicarboxylic acid, a fluoride, spiculisporic acid, a molybdate, an azole compound, a phosphonate, a phosphinate, an amine salt, a borate or mixtures thereof.

### Claim 4 (depends on 1)

The heat transfer system of claim 1, wherein the heat transfer fluid further comprises at least one metal ion selected from the group consisting of calcium, magnesium, strontium, zinc or combinations thereof.

### Claim 5

A method of reducing corrosion in a heat transfer system comprising at least one component comprising magnesium or a magnesium alloy, the method comprising
contacting the at least one component with a heat transfer fluid comprising
about 5% to about 99% by weight of freezing point-depressing agent;
about 1% to about 95% by weight of water; and
a corrosion inhibiting composition formed by combining components comprising:
(a) an inorganic phosphate;
(b) a water soluble polyelectrolyte polymer dispersant; and
(d) at least one additional component comprising at least one of a C4-C22 aliphatic or aromatic mono- or dicarboxylic acid, a silicate and a silicate stabilizing silicone, and mixtures thereof.