RU2294981C1 - Rust reforming agent - Google Patents

Abstract

FIELD: mechanical engineering; chemical treatment of surfaces of metals; prevention of corrosion; preparation of metal surfaces for application of paints and varnishes without preliminary removal of corrosion; treatment of weld seams and oil and gas pipe lines coated with scale.

SUBSTANCE: proposed rust reforming agent contains the following components, mass-%: arthophosphoric acid (85%), 45-65; ferro-prussiate -potassium ferrocyanide, 3.0-4.0; aluminum nitrate, 2.0-3.0; zinc nitrate, 0.5-1.5 and fluorocarbon compound, 0.01-0.1 of total formula

where RF=C₆F₁₃CO-, C₈F₁₇CO-, CF₃О(C₃F₆О)_3-12-CF(CF₃)CO-, at n=2,3,4

at m=0-7 or

and water, up to 100%. Protective film may be used as primer for application of paints and varnishes.

EFFECT: enhanced durability of film formed on metal excluding further corrosion due to protection effect arising between film and parent metal.

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Description

The invention relates to the field of mechanical engineering, namely to the creation of a rust converter for chemical treatment of a metal surface, which prevents metal corrosion and is intended to prepare the metal surface for applying paint and varnish and other coatings without first removing corrosion products. In addition, the proposed corrosion converter can be used for processing products from ferrous metals, including those operating in a marine climate, in mechanical engineering, in transport, etc. The rust converter can also be used to process welds and metal surfaces covered with scale, oil and gas pipelines.

Known rust converter containing phosphoric acid, potassium ferruginous (yellow blood salt), nitrate aluminum and water (see RF patent No. 2205896, IPC C 23 C 22/20, 2003).

However, the known rust converter in its use has the following disadvantages:

- insufficient durability formed on the surface of the metal after treatment with a rust converter protective film that prevents further corrosion,

- the need for reprocessing of corrosion sites on the metal surface,

- insufficient quality of the formed protective film, which serves as a primer for subsequent application of coatings,

- the duration of the surface treatment of the metal with a rust converter.

The objective of the invention is the creation of a rust converter.

The technical result when using the proposed rust converter is the formation of a durable protective film on the metal surface after its processing by the rust converter, which prevents further corrosion, the formation of a protective film that serves as a primer for subsequent application of paint coatings, additional protection of the metal surface from corrosion due to the occurrence between the formed film and the main metal of the tread effect, as well as acceleration of the process of processing s.

The technical result is achieved by combining the components of the proposed rust converter, using a fluorocarbon compound of the "ion pair" type of the proposed general formula in its composition, as well as the quantitative ratio of the components included in the converter.

The proposed rust converter contains phosphoric acid, potassium ferruginous (yellow blood salt), nitrate aluminum and water, and also additionally contains zinc nitrate and a fluorocarbon compound of the "ion pair" type of the general formula:

where R _F = C ₆ F ₁₃ CO—, C ₈ F ₁₇ CO—, CF ₃ O (C ₃ F ₆ O) _3-12 —CF (CF ₃ ) CO—;

when n = 2, 3, 4;

when m = 0-7;

or

in the following quantitative content of components, wt.%:

phosphoric acid (85%) 45-65 aluminum nitrate 2.0-3.0 zinc nitrate 0.5-1.5 potassium ferruginate (yellow blood salt) 3.0-4.0 fluorocarbon compound (ion pair) 0.01-0.1 water the rest is up to 100%

Among the essential features characterizing the proposed rust converter, the distinctive are:

- introduction of zinc nitrate to the rust converter,

- introduction to the rust converter of a fluorocarbon compound of the "ion pair" type of the general formula:

where R _F = C ₆ F ₁₃ CO—, C ₈ F ₁₇ CO—, CF ₃ O (C ₃ F ₆ O) _3-12 —CF (CF ₃ ) CO—;

when n = 2, 3, 4;

when m = 0-7;

or

- quantitative content of components, wt.%:

phosphoric acid (85%) 45-65 aluminum nitrate 2.0-3.0 zinc nitrate 0.5-1.5 potassium ferruginate (yellow blood salt) 3.0-4.0 fluorocarbon compound (ion pair) 0.01-0.1 water the rest is up to 100%

Experimental studies of metal surfaces treated with the proposed rust converter, and then full-scale testing of standard kits, showed its high efficiency. It was found that the proposed rust converter has a low surface tension (22 mH / m), which significantly accelerates the processing of metal surfaces due to the easier and faster penetration of the rust converter into surface microcracks and to a depth of the rust layer of more than 100 μm. Moreover, in the process of processing a metal surface, residual centers of corrosion are excluded, for example, in microcracks and surface roughness. At the same time, it was found that a high-quality film is formed on the metal surface, which leads to an increase in the reliability of metal protection against corrosion and to an increase in durability.

The proposed rust converter is obtained by dissolving the constituent components in water with mechanical stirring and a temperature of 20-30 ° C. In this case, standard components manufactured by the industry are used: orthophosphoric acid in accordance with GOST - 6552-80, nitric aluminum (9-hydrous) in accordance with GOST - 3757-75, nitric zinc in accordance with GOST - 5106-77, potassium ferruginous in accordance with GOST 6816-79 and distilled water according to GOST 6709-72.

The proposed rust converter is applied to the metal surface to be treated without first removing corrosion products from it by any known method (spray, brush or swab), dried at a temperature of 20-30 ° C for 1-4 hours, and the paintwork is applied depending on the thickness a layer of rust or scale after 12-18 hours after drying.

Table 1 presents the characteristics of the area of destruction and the area of delamination of the coating after processing metal samples with the compositions of the proposed and known rust converters according to the results of comparative tests.

The following compositions of the proposed rust converter were used.

Composition No. 1: phosphoric acid (85%) in an amount of 65 wt.%, Aluminum nitrate (9-aqueous) in an amount of 2.0 wt.%, Zinc nitrate (6-aqueous) in an amount of 1.5 wt.%, Potassium ferruginous-synergy (yellow blood salt) in an amount of 3.0 wt.%, fluorocarbon compound ("ion pair") R _F = C ₈ F ₁₇ CO-, Q = NHC ₃ H ₆ N (CH ₃ ) ₂ and Z = CF ₃ (CF ₂ ) ₃ COO in an amount of 0.01 wt.%, Water - the rest is up to 100%.

Composition No. 2: phosphoric acid (85%) in an amount of 45 wt.%, Aluminum nitrate (9-aqueous) in an amount of 3.0 wt.%, Zinc nitrate (6-aqueous) in an amount of 0.5 wt.%, Potassium ferruginous-synergy (yellow blood salt) in an amount of 4.0 wt.%, fluorine-containing compound ("ion pair") R _F = С ₆ F ₁₃ СО-, Q = NHC ₂ Н ₄ N (СН ₃ ) ₂ and Z = CF ₃ O (C ₃ F ₆ O) ₆ -CF (CF ₃ ) COO in an amount of 0.01 wt.%, Water - the rest is up to 100%.

Strength and corrosion resistance of the coating were tested in accordance with GOST 15140-78 by the method of lattice notches in conditions simulating a hot marine climate. In each of the two test series, each of the above compositions of the proposed rust converter processed 12 plates of size 70 × 150 × 1.5 mm, made of steel st-20 according to GOST 16523-70. The rust layer on the plates was 50-90 microns. After processing with the proposed rust converter and the rust converter, the prototype, steel plates were placed in a container above a pair of 3% aqueous sodium chloride at a temperature of 80 ± 5 ° C. Samples were aged for 400 hours. After 200 and 400 hours, measurements of the area of destruction of the coating were carried out. The measurement results are shown in table 1.

The manufacturing technology of the components of the proposed rust converter is standard, does not require the use of specific technological equipment and includes the processes of mixing the initial components of the converter and applying it to a solid metal surface.

Thus, the proposed rust converter has advantages over a known converter of the same purpose.

Claims (1)

A rust converter containing orthophosphoric acid, potassium ferruginous-hydrogen sulfide — yellow blood salt, aluminum nitrate and water, characterized in that it additionally contains zinc nitrate and a fluorocarbon compound of the general formula

where R _F = C ₆ F ₁₃ CO—, C ₈ F ₁₇ CO—, CF ₃ O (C ₃ F ₆ O) _3-12 —CF (CF ₃ ) CO—;

when n = 2, 3, 4;

at m = 0-7 or

in the following quantitative content of components, wt.%: Phosphoric Acid (85%) 45-65 Potassium ferruginate - yellow blood salt 3.0-4.0 Aluminum nitrate 2.0-3.0 Zinc Nitrate 0.5-1.5 Fluorocarbon compound 0.01-0.1 Water The rest is up to 100%