BRAZING PRE-FLUX COATING

• US 20130299564A1
• Filed: 08/22/2011
• Published: 11/14/2013
• Est. Priority Date: 08/23/2010
• Status: Abandoned Application

• Current Assignee: Sapa AS
• Original Assignee: Sapa AS
• Inventors: Insalaco, Jeffrey L., Steiner, Dagmar, Nordlien, Jan Halvor
• Application Number:
  US13/817,834
• Publication Number:
  US 20130299564A1
• Time in Patent Office: Days
• US Class Current: 228/223
• CPC Class Codes: B23K 1/0012 Brazing heat exchangers
• CPC Class Codes: B23K 1/203 Fluxing, i.e. applying flux onto surfaces
• CPC Class Codes: B23K 2101/14 Heat exchangers
• CPC Class Codes: B23K 2103/10 Aluminium or alloys thereof
• CPC Class Codes: B23K 35/3605 Fluorides
• CPC Class Codes: B23K 35/3613 Polymers, e.g. resins
• CPC Class Codes: B23K 35/362 Selection of compositions of fluxes B23K35/365, B23K35/368 take precedence
• CPC Class Codes: B23K 35/365 Selection of non-metallic compositions of coating materials either alone or conjoint with selection of soldering or welding materials
• CPC Class Codes: C22C 21/00 Alloys based on aluminium
• CPC Class Codes: Y10T 428/31667 Next to addition polymer from unsaturated monomers, or aldehyde or ketone condensation product

Abstract

Pre-flux coating for the manufacturing of components by brazing, in particular manufacturing of heat exchangers of aluminium components including one or more fluxes and filler materials. The coating is composed of fluxes in the form of potassium aluminum fluoride K_1-3AIF_4-6, potassium trifluoro zincate, KZnF₃, lithium aluminum fluoride Li₃AIF₆, filler material in the form of metallic Si particles, Al—Si particles and/or potassium fluoro silicate K₂SiF₆, and solvent and binder containing at least 10% by weight of a synthetic resin which is based, as its main constituent, on methacrylate homopolymer or methacrylate copolymer. The potassium aluminium fluoride, K_1-3AIF_4-6 is a flux including KAIF₄, K₂AIF₅, K₃AIF₆ or a combination of these fluxes. The coating may be blended as a one layer coating or a multi layer coating, whereby as a one layer coating all flux components and filler material are mixed with binder and solvent, and whereby as a multi layer coating the flux components and filler material are mixed as separate coatings with binder and solvent.

Claims

1. Pre-flux coating for the manufacturing of components by brazing, in particular manufacturing of heat exchangers of aluminium components including one or more fluxes and filler material,

characterized in that

the coating is composed of fluxes in the form of potassium aluminum fluoride K_1-3AlF_4-6, potassium trifluoro zincate, KZnF₃, lithium aluminum fluoride Li₃AlF₆, filler material in the form of metallic Si particles, Al—

Si particles and/or potassium fluoro silicate K₂SiF₆, and solvent and binder containing at least 10% by weight of a synthetic resin which is based, as its main constituent, on methacrylate homopolymer or methacrylate copolymer.

2. Coating according to claim 1,

characterized in that the coating is blended as a one layer coating or a multi layer coating, whereby as a one layer coating all flux components and filler material are mixed with binder and solvent, and whereby as a multi layer coating the flux components and filler material are mixed as separate coatings with binder and solvent.

3. Coating according to claim 1,

characterized in that the multilayer coating includes 2, 3 or 4 individually blended coating elements each based on binder and solvent with one or more flux component and/or filler material or filler generating material.

4. Coating according claim 1,

characterized in that

the potassium aluminum fluoride, K_1-3 AlF_4-6 is a flux including KAlF₄, K₂AlF₅, K₃AlF₆ or a combination of these fluxes.

5. Coating according to claim 1 where the aluminium component is based on an aluminium alloy with high Mg content,

characterized in that

an additional flux in the form of cesium aluminum fluoride CsAlF₄ is added.

6. Coating according to claim 1,

characterized in that

the ratio of particles and binder is between 3:

1 to 4;

1.

7. Coating according to claim 1,

characterized in that

the ratio of particles of the different components of the coating corresponds to a load of 0-5.2 g/m²Si, 1.41-16 g/m²Zn flux (KZnF₃), 2.2-9.2 g/m² potassium flux (KAlF₄/K₃AlF₆) and 0.1-5 g/m²Li flux (Li₃AlF₆) g/m².

8. Application of the coating on an aluminium component according to claim 1 as a one layer coating or a multi layer coating, whereas as a one layer coating all flux components and filler material are mixed with binder and solvent and provided on the component in one operation, and whereas as a multi layer coating the flux components and filler material are mixed as separate coatings with binder and solvent and applied individually one at a time preferably with intermediate curing.

9. Application according to claim 8 where the coating is provided on the component by roll coating or dip coating.