RU2441737C2 - Active basis of flux for low temperature brazing - Google Patents

Abstract

FIELD: non-ferrous metallurgy.

SUBSTANCE: invention can be used for low temperature brazing of non-ferrous metals and their alloys, for example, copper, with tin-lead solders in production of radiators, heaters, heat exchangers and other automobile equipment. Active base of the flux includes a mixture of salts of 4-amino-1, 2, 3-triazol bromine acids, 1, 2, 3-triazol bromine acids, imidazole bromine acids, 5-amino-tetrazol bromine acids, benzene azimide bromine acids, hydrazin bromine acids, semicarbazide hydrobromide. The salts of organic polynitrogen bases used have linear or cyclic structure and include 2 or more atoms nitrogen. One or several of them is a strong base ensuring flux neutrality.

EFFECT: use of active flux base ensures reduction of flux corrosion activity and increase of its fluxing activity.

2 cl, 1 tbl, 40 ex

Description

The present invention relates to the field of soldering production, namely to the formation of a system of components (materials) for soldering, in particular to the development of compositions for flux bases, and can be used for low-temperature soldering of non-ferrous metals or their alloys, such as copper and brass, in areas of technological production cycle of radiators, heaters, heat exchangers and other automotive equipment.

The quality of the compound obtained by soldering depends on the preliminary processing of the surface of the brazed metal and solder flux. The key characteristics of the flux are high fluxing activity with respect to oxide films and low corrosion activity with respect to brazed metals.

Solder fluxes, as a rule, consist of an active base, solvent and filler components (surfactants, corrosion inhibitors, etc.). The choice of the active basis of the flux determines the properties of the flux and its characteristics, for example, Nikitinsky A.M., Gerasimov EA, Pigalov S.A. The effect of various chemical compounds on the technological properties of fluxes for brazing copper and brass // Welding production. 2004. No. 6. S.5-10 .; Nikitinsky A.M., Pigalov S.A., Gerasimov E.A., Egorychev S.V. Optimization of the flux composition for brazing copper alloys with fusible solders // Welding production. 2006. No5. S.17-20; Nikitinsky A.M., Pigalov S.A., Egorychev S.V., Gerasimov E.A. Investigation of the corrosion activity of fluxes used in brazing copper and its alloys // Welding production. 2006. No. 6. S.18-21.

The invention is aimed at creating an active flux base for low-temperature brazing of tin-lead solders.

Currently, in soldering production, such groups of substances as acids, metal salts, bases are used as active flux bases.

Thus, active flux bases for low-temperature brazing of lead or brass-copper elements are known (for example, RU 2069135 C1, 11/20/1996; RU 2008195 C1, 02/28/1994), which are acids, in particular hydrobromic acid.

The disadvantage of such fluxes is the excess of MPC for acid in the air of the working area.

The active flux bases used for the low-temperature brazing of copper or its alloys are known, which are an inorganic salt - zinc chloride, or a mixture of inorganic salts: zinc chloride, sodium chloride, and ammonium chloride, as well as a weak organic base - urea (for example, RU 2285600 C1 , 10/20/2006; RU 2243074 C1, 12/27/2004).

A significant drawback of zinc chloride-based fluxes is its high corrosivity, leading to intense corrosion of soldered joints. This is due to the hydrolysis of zinc chloride in air, which results in the formation of chlorine anions and compounds poorly soluble in water, namely hydroxychloride and zinc hydroxide. Therefore, fluxes based on zinc chloride require a long and repeated washing of flux residues and drying of products after soldering.

Urea-based fluxes (weak organic base) have low fluxing activity (Sp - area of solder spreading in copper 156 mm ² , in brass - 231 mm ² ).

As a prototype, an active flux base for low-temperature brazing, known according to RU 2080228 C1, 05/27/1997, was selected. This base is characterized by the fact that it uses organic compounds - hydrohalide or hydrophosphate of guanidine or substituted guanidine, or one or more hydrogen halide or five-membered hydrogen phosphate a heterocyclic nitrogen-containing compound of the formula C _x N _y H ₃ , where x is 1 or 2, y is 4 or 5, or a mixture of these guanidine compounds and a heterocyclic amine.

The disadvantage of this active base is the high corrosivity due to the free presence of hydrogen halide or phosphoric acid.

When using the inventive active flux base, the technical result achieved by the invention is to reduce the corrosive activity of the flux while increasing its fluxing activity.

An advantage of the invention is the absence of active metal chlorides in the active base, which reduces the complexity of manufacturing radiators due to the exclusion from the process of an additional stage of washing flux residues after soldering.

In addition, the content of heavy metals in the wastewater of the enterprise is reduced, and the environmental conditions of the workplace of the soldering iron are improved.

The technical result is achieved by the fact that in the active flux base for low-temperature brazing containing bromides of poly-nitrogen bases, the mixture of salts selected from 4-amino-1,2,4-triazole bromide, 1,2,3-triazole bromide, is contained as bromides imidazole bromide, 5-amino-tetrazole bromide, benzotriazole bromide, hydrazine hydrobromide, semicarbazide bromide.

It is advisable to reduce the corrosivity of using a mixture of salts of organic polyazitous bases of a linear or cyclic structure containing 2 or more nitrogen atoms, of which one or more is a strong base, providing flux neutrality.

A characteristic feature of the active base is that when it is heated in the composition of the flux, the mixture of bromides of organic polyazitous bases interacts with the oxides of the soldered metal and solder, forming complex compounds. The flux provides improved wetting by solder of the brazed surface, helps to increase the spreading area of the solder with the formation of a durable solder joint, also has long-term stability at high temperature, does not leave soot and residues after soldering.

Table 1 shows examples of specific formulations of the active base of the flux and the properties of the flux with the claimed active base.

The fluxing activity of the formed component systems was tested by the ability of molten solder to spread over the base metal. As the base metal, plates 50 × 50 × 0.5 mm in size made of copper M1 and brass L63 were used. Solder-mounted plates were placed in a furnace with a temperature of 350 ± 10 ° С. After cooling, the area of solder spreading was determined.

The corrosion activity of the flux was evaluated by the amount of current passing between the electrodes: solder (POSSU 30-2) - brazed metal (copper M1 or brass L63), placed in a 100 ml flux solution. A flux was used in each measurement a new one.

The composition of the flux obtained with the claimed active base can be illustrated by the following examples.

Example No. 1.

1. semicarbazide bromide - 10%

2.2,2,3-triazole bromide - 10%

3. hydrazine bromide - 4%

4. Surfactant - 0.1%

5. water - the rest.

Example No. 2.

1. semicarbazide bromide - 10%

2.2,2,3-triazole bromide - 10%

3. hydrazine bromide - 8%

4. Surfactant - 0.1%

5. water - the rest.

Example No. 3.

1. semicarbazide bromide - 10%

2.2,2,3-triazole bromide - 10%

3. hydrazine bromide - 10%

4. Surfactant - 0.1%

5. water - the rest.

Example No. 4.

1. semicarbazide bromide - 10%

2.2,2,3-triazole bromide - 10%

3. hydrazine bromide - 12%

4. Surfactant - 0.1%

5. water - the rest.

Example No. 5.

1. semicarbazide bromide - 5%

2. 4-amino-1,2,4-triazole bromide - 5%

3. Surfactant - 0.1%

4. water - the rest.

Example No. 6.

1. semicarbazide bromide - 10%

2. 4-amino-1,2,4-triazole bromide - 5%

3. Surfactant - 0.1%

4. water - the rest.

Example No. 7.

1. semicarbazide bromide - 15%

2. 4-amino-1,2,4-triazole bromide - 5%

3. Surfactant - 0.1%

4. water - the rest.

Example No. 8.

1.4-amino-1,2,4-triazole bromide - 5%

2. semicarbazide bromide - 10%

3. hydrazine bromide - 4%

4. Surfactant - 0.1%

5. water - the rest.

Example No. 9

1. imidazole bromide - 5%

2. semicarbazide bromide - 10%

3. Surfactant - 0.1%

4. water - the rest.

Example No. 10

1. imidazole bromide - 10%

2. semicarbazide bromide - 10%

3. Surfactant - 0.1%

4. water - the rest.

Example No. 11

1. imidazole bromide - 15%

2. semicarbazide bromide - 10%

3. Surfactant - 0.1%

4. water - the rest.

Example No. 12

1. 1,2,3-triazole bromide - 5%

2. semicarbazide bromide - 10%

3. Surfactant - 0.1%

4. water - the rest.

Example No. 13

1. 1,2,3-triazole bromide - 10%

2. semicarbazide bromide - 10%

3. Surfactant - 0.1%

4. water - the rest.

Example No. 14

1. 1,2,3-triazole bromide - 15%

2. semicarbazide bromide - 10%

3. Surfactant - 0.1%

4. water - the rest.

Example No. 15

1.2,2,3-benzotriazole bromide - 5%

2. 4-amino-1,2,4-triazole bromide - 15%

3. Surfactant - 0.1%

4. water - the rest.

Example No. 16

1.2,2,3-benzotriazole bromide - 10%

2. 4-amino-1,2,4-triazole bromide - 15%

3. Surfactant - 0.1%

4. water - the rest.

Example No. 17.

1.2,2,3-benzotriazole bromide - 10%

2. 4-amino-1,2,4-triazole bromide - 15%

3. Surfactant - 0.1%

4. water - the rest.

Example No. 18.

1.4-amino-1,2,4-triazole bromide - 5%

2. semicarbazide bromide - 10%

3. hydrazine bromide - 4%

4. Surfactant - 0.1%

5. water - the rest.

Example No. 19.

1. 4-amino-1,2,4-triazole bromide - 10%

2. semicarbazide bromide - 10%

3. Surfactant - 0.1%

4. water - the rest.

Example No. 20.

1. 4-amino-1,2,4-triazole bromide - 15%

2. semicarbazide bromide - 10%

3. Surfactant - 0.1%

4. water - the rest.

Example No. 21.

1. 5-amino-tetrazole bromide - 5%

2. semicarbazide bromide - 10%

3. Surfactant - 0.1%

4. water - the rest.

Example No. 22.

1.5-amino-tetrazole bromide - 10%

2. semicarbazide bromide - 10%

3. Surfactant - 0.1%

4. water - the rest.

Example No. 23.

1.5-amino-tetrazole bromide - 15%

2. semicarbazide bromide - 10%

3. Surfactant - 0.1%

4. water - the rest.

Example No. 24.

1. 4-amino-1,2,4-triazole bromide - 15%

2.2,2,3 triazole bromide - 5%

3. Surfactant - 0.1%

4. water - the rest.

Example No. 25.

1. 4-amino-1,2,4-triazole bromide - 15%

2.2,2,3 triazole bromide - 10%

3. Surfactant - 0.1%

4. water - the rest.

Example No. 26.

1. 4-amino-1,2,4-triazole bromide - 15%

2. semicarbazide bromide - 5%

3. hydrazine bromide - 4%

4. Surfactant - 0.1%

5. water - the rest.

Example No. 27.

1. 4-amino-1,2,4-triazole bromide - 15%

2. semicarbazide bromide - 10%

3. hydrazine bromide - 8%

4. Surfactant - 0.1%

5. water - the rest.

Example No. 28.

1. 4-amino-1,2,4-triazole bromide - 15%

2. semicarbazide bromide - 15%

3. hydrazine bromide - 4%

4. Surfactant - 0.1%

5. water - the rest.

Example No. 29.

1. semicarbazide bromide - 10%

2. 4-amino-1,2,4-triazole bromide - 15%

3. hydrazine bromide - 4%

4. Surfactant - 0.1%

5. water - the rest.

Example No. 30.

1. semicarbazide bromide - 10%

2. 4-amino-1,2,4-triazole bromide - 15%

3. hydrazine bromide - 8%

4. Surfactant - 0.1%

5. water - the rest.

Example No. 31.

1. semicarbazide bromide - 10%

2. 4-amino-1,2,4-triazole bromide - 15%

3. hydrazine bromide - 10%

4. Surfactant - 0.1%

5. water - the rest.

Example No. 32.

1. semicarbazide bromide - 10%

2. 4-amino-1,2,4-triazole bromide - 15%

3. hydrazine bromide - 12%

4. Surfactant - 0.1%

5. water - the rest.

Example No. 33.

1. 1,2,3-triazole bromide - 10%

2. semicarbazide bromide - 5%

3. hydrazine bromide - 4%

4. Surfactant - 0.1%

5. water - the rest.

Example No. 34.

1. 1,2,3-triazole bromide - 10%

2. semicarbazide bromide - 5%

3. hydrazine bromide - 8%

4. Surfactant - 0.1%

5. water - the rest.

Example No. 35.

1. 1,2,3-triazole bromide - 10%

2. semicarbazide bromide - 5%

3. hydrazine bromide - 10%

4. Surfactant - 0.1%

5. water - the rest.

Example No. 36.

1. 1,2,3-triazole bromide - 10%

2. semicarbazide bromide - 5%

3. hydrazine bromide - 12%

4. Surfactant - 0.1%

5. water - the rest.

Example No. 37.

1. 4-amino-1,2,4-triazole bromide - 10%

2. semicarbazide bromide - 5%

3. hydrazine bromide - 4%

4. Surfactant - 0.1%

5. water - the rest.

Example No. 38.

1. 4-amino-1,2,4-triazole bromide - 10%

2. semicarbazide bromide - 5%

3. hydrazine bromide - 8%

4. Surfactant - 0.1%

5. water - the rest.

Example No. 39.

1. 4-amino-1,2,4-triazole bromide - 10%

2. semicarbazide bromide - 5%

3. hydrazine bromide - 10%

4. Surfactant - 0.1%

5. water - the rest.

Example No. 40.

1. 4-amino-1,2,4-triazole bromide - 10%

2. semicarbazide bromide - 5%

3. hydrazine bromide-12%

4. Surfactant - 0.1%

5. water - the rest.

Non-ionic surfactants are used as a surface-active substance in the flux for low-temperature brazing of copper and brass.

The above examples do not exhaust all possible flux compositions using the claimed active base.

Claims (2)

1. The active base of the flux for low-temperature brazing, containing bromides of organic polyazitous bases, characterized in that as bromides of organic polyazitous bases, it includes a mixture of salts selected from 4-amino-1,2,4-triazole bromic acid, 1,2 , 3-triazole bromic acid, imidazole bromic acid, 5-amino-tetrazole bromic acid, benzotriazole bromic acid, hydrazine hydrobromide, semicarbazide bromide. 2. The active base of the flux according to claim 1, characterized in that the bromides of organic polyazitous bases used in it have a linear or cyclic structure and contain 2 or more nitrogen atoms, while one or more of them is a strong basis for ensuring the neutrality of the flux.