RU2572688C1 - Solution for metal surface phosphating - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: solution for metal surface phosphating contains, g/l: Zn²⁺ 4.55-8.0, P₂O₅ 7.8-14.0, NO₃ ^- 9.1-16.0, Mn²⁺ 1.17-2.8, Ni²⁺ 0.07-0.2, F^- 0.52-0.8, carboxylic acid 0.19-0.3, water - the remaining part, with ratio of Mn²⁺ ions to Zn²⁺ ions constituting (0.257-0.615):(1.0-1.758). As carboxylic acid solution contains dioxysuccinic, oxalic or citric acid.

EFFECT: invention makes it possible to obtain finely crystalline phosphate film with optimal weight of phosphate coating at temperature of phosphating 55-70 degrees, and provides obtaining of coatings with high protective and wear-resistant properties.

2 cl, 2 tbl

Description

The invention relates to the chemical treatment of a metal surface by applying a phosphate coating and can be used in the automotive industry, instrumentation, metallurgy and hardware industry to obtain coatings with high protective and wear-resistant properties.

Known solution (RF patent 2111282), containing, g / l:

Ni ²⁺ 0,000-0,5 P ₂ O ₅ 1.7-7.0 NO ₃ ^- 1,5-5,2 F ^- 0.05-0.5 Manganese (II) nitrate waste 2-20 Production Waste - Zinc Concentrate 3-25,

moreover, the waste product - zinc concentrate - contains, wt.%:

Total P ₂ O ₅ not less than 25 zn ²⁺ not less than 25 Mn ²⁺ 4-8 Water no more than 30,

and the waste of manganese (II) nitrate contains, wt.%:

Mn ²⁺ 72.0-80.3

one or more impurities from the group aluminum perchlorate, formic acid, ammonium formate, manganese citrate, manganese hydroxides - the rest.

Closest to the invention in technical essence and the achieved result is a solution (RF patent 2159299) for phosphating a metal surface, containing, wt.%:

Mn ²⁺ 5.7-6.3 NO ₃ ^- 2-3 P ₂ O ₅ 17.5-21.5 ni ²⁺ 0.1-0.2 Zn ²⁺ 0.8-1.2 triethanolamine 0.005-0.015 water rest.

The use of this solution provides an increase in the service life of parts, increased wear resistance, and improved anti-friction properties.

The disadvantage of this solution is to obtain a coarse-grained phosphate coating with a large mass of phosphate coating. With a large mass of phosphate coating, a very high wear of the phosphate film occurs in the initial period of the test. The thicker the film, the longer the break-in period and the weight loss of the sample. The intense wear of a thick phosphate film is explained by the lower adhesion strength of external phosphate crystals compared to crystals adjacent directly to the metal surface.

The objective of the invention is to provide a solution for phosphating a metal surface, providing a fine crystalline phosphate film with an optimal phosphate coating mass at a phosphating temperature of 55-70 ° C, providing high protective properties and wear resistance of the coating.

The problem is achieved in that a solution for phosphating a metal surface, containing, g / l:

Zn ²⁺ 4,55-8,0 P ₂ O ₅ 7.8-14.0 NO ₃ ^- 9.1-16.0 Mn ²⁺ 1.17-2.8 ni ²⁺ 0.07-0.2 F ^- 0.52-0.8 carboxylic acid 0.19-0.3 water rest,

moreover, the ratio of Mn ²⁺ ions to Zn ^{2+ ions} is (0.257-0.615) :( 1.0-1.758).

The phosphate solution as a carboxylic acid contains dioxanosuccinic, oxalic or citric acid.

Carboxylic acids reduce the size of the crystals of the phosphate coating.

Fluorine ions increase the adhesion of the coating to the surface of the threaded connection and reduce the temperature of phosphating.

The proposed solution for phosphating a metal surface is obtained by mixing water, zinc and phosphorus-containing raw materials, followed by the introduction of nitric acid and manganese-containing raw materials in amounts indicated in Table 1. Then, modifying additives are introduced into the solution: one of the above carboxylic acids and a raw material containing nickel and fluorine.

This invention relates to surface treatment of a pipe joint with a phosphating solution to form a phosphate coating having high protective properties and wear resistance.

Steel pipes are usually connected to each other by means of a sleeve, while a threaded sleeve is put on the ends of the pipes equipped with a thread on the inner surface.

Zinc-manganese phosphate concentrate is used to protect the surface of threaded joints of couplings against corrosion and improve anti-wear properties.

The tests were carried out on the segments of couplings with thread size 50 × 70 mm, steel grade 22ГЮ. The processing method is immersion.

The metal surface to be treated before the phosphating operation was degreased, washed thoroughly and subjected to treatment with an activator.

The detergent used was Foscon 203-1 TU 2499-110-10964029

concentration, g / l twenty temperature, ° С 50-60 processing time, min 10

Rinsing with tap water

temperature, ° С 20-35 processing time, min 1-2

The activation of the metal surface was carried out by the phosphatization activator Foscon 473 TU 2149-283-10964029

concentration, g / l 1,5 temperature, ° С room processing time, min 2

Phosphating a metal surface

temperature, ° С 55-70 processing time, min 10

Rinsing with tap water

temperature, ° С 20-35 processing time, min 1-2

Drying

temperature, ° С 110 processing time, min 10

The following phosphate coating characteristics were evaluated.

1. Appearance of phosphate coating

The appearance of the phosphate coating is determined visually according to GOST 9.301.

The appearance of the coating obtained using the present invention, from light gray to dark gray.

2. The thickness of the phosphate coating

The thickness of the phosphate coating is determined by a “Constant K5” thickness gauge with a specialized ID1 sensor. The thickness of the phosphate coating is 8-15 microns.

3. Protective properties of the phosphate coating

The protective properties of the phosphate coating are determined according to GOST 9.302 (paragraph 6).

The essence of the invention is illustrated by the following examples.

For research prepared 5 options phosphating solutions and 1 option of the prototype.

The compositions of the proposed phosphating solution and the prototype are shown in table 1.

The test results are shown in table No. 2

As can be seen from the examples (see table 2, etc. 2, 3, 4), the content of the components in the claimed range provides for obtaining a crystalline coating having high protective properties and high antiwear properties.

Changes in the content of components below or above the declared limits (see table 2, etc. 1, 5) leads to a decrease in protective properties.

Example 6 describes the properties of the prototype.

Using the proposed invention provides the following technical and economic advantages:

- high protective properties of the surface of the threaded pipe joints;

- high wear-resistant properties of threaded pipe joints;

- profitability in connection with a low consumption rate;

- The phosphating solution is technologically advanced and easy to use.

Claims (2)

1. A solution for phosphating a metal surface, containing, g / l:
Zn ²⁺ 4,55-8,0 P ₂ O ₅ 7.8-14.0 NO ₃ ^- 9.1-16.0 Mn ²⁺ 1.17-2.8 Ni ²⁺ 0.07-0.2 F ^- 0.52-0.8 carboxylic acid 0.19-0.3 water rest,
moreover, the ratio of Mn ²⁺ ions to Zn ^{2+ ions} is (0.257-0.615) :( 1.0-1.758). 2. The solution according to p. 1, characterized in that as the carboxylic acid, it contains dioxinosuccinic, oxalic or citric acid.