Boric acid free flux

Patent metadata

Field	Value
Publication number	US-10058957-B2
Application number	US-201514885868-A
Country	US
Kind code	B2
Filing date	Oct 16, 2015
Priority date	Mar 15, 2013
Publication date	Aug 28, 2018
Grant date	Aug 28, 2018

Abstract

The invention described herein pertains generally to boric acid free flux composition wherein in some embodiments, a phthalocyanine pigment is used to effect a color change at activation temperature.

First claim

What is claimed is:

1. A boric acid free paste flux composition which comprises the following components:

water
balance

a wetting agent
0.25-0.50%

potassium bifluoride (KHF 2 )
12.4-16.8%

fumed silica (SiO 2 )
0.71-1.35%

potassium tetraborate (K 2 B 4 O 7 •4H 2 0)
29.5-34.8%

potassium fluoroborate (KBF 4 )
29.5-34.8%

pigment
0.50-0.98%

wherein amounts of said components are on the basis of weight percentages with respect to a combined total of 100% by weight.

2. The paste flux composition of claim 1 wherein
said pigment is a phthalocyanine pigment which changes from colored to colorless at a temperature of approximately 500-600° C.

3. A process of using a boric acid free paste flux of claim 1 which comprises the step of:
adding a phthalocyanine pigment to said flux.

4. The process of claim 3 wherein
said step of adding a phthalocyanine pigment effects a color change at an activation temperature of said flux.

5. The process of claim 4 wherein
said color change is effected at an activation temperature of between approximately 500-600° C.

6. A boric acid free paste flux, comprising:
a wetting agent in a weight percentage in the range of 0.25 to 0.50%;
an etchant in a weight percentage in the range of 12.4 to 16.8%;
an emulsifying agent in a weight percentage in the range of 0.71 to 1.35%;
potassium tetraborate in a weight percentage in the range of 29.5 to 34.8%;
potassium fluoroborate in a weight percentage in the range of 29.5 to 34.8%; and
pigment in a weight percentage in the range of 0.50 to 0.98%;
wherein the balance is water.

7. The boric acid free paste flux of claim 6 , wherein said flux is green in color.

8. The boric acid free paste flux of claim 6 , wherein said flux is fully active in the temperature range of 566° to 871° C.

9. The boric acid free paste flux of claim 6 , wherein said etchant is potassium bifluoride.

10. The boric acid free paste flux of claim 6 , wherein said emulsifying agent is fumed silica.

11. The boric acid free paste flux of claim 6 , wherein said pigment is a phthalocyanine pigment.

12. The boric acid free paste flux of claim 6 , wherein said flux changes color at a temperature within the range of approximately 500 to 600° C.

Assignees

• Lincoln Global Inc

Inventors

• Howard Robert A

Classifications

• B23K35/3601

  with inorganic compounds as principal constituents · CPC title

• B23K35/025

  Pastes, creams or slurries · CPC title

• B23K1/0006

  Exothermic brazing · CPC title

• B23K35/3607

  Silica or silicates · CPC title

• B23K35/3605 Primary

  Fluorides · CPC title