The method of forming a copper coating on the surface of iron or its alloys

 

(57) Abstract:

The method of forming a copper coating on the surface of iron or its alloys relates to methods of applying metallic coatings on iron-containing surface of the products carried out by a simple application of this surface chemical reagents. The method can be used for applying solid copper coatings on steel or cast iron surface and can replace galvanic methods of applying such coatings. To obtain a solid copper film surface of iron or its alloys covered with a suspension containing the copper powder and the solution of reducing agent with respect to copper ions, which added a strong acid in a quantity sufficient to ensure that the acidity of the solution had a pH < 3. 11 C.p. f-crystals.

The invention relates to methods of applying metallic coatings to the surface of articles made of iron or its alloys, by decomposition of the suspension of the covering substance. It can be used in various industries for the formation of copper coatings on the surfaces of steel or cast iron and can replace galvanic methods of applying such coatings.

Known is dcosta on the pre-machined steel surface with subsequent surface-its plastic deformation. In this case, the deposition of copper is a contact method from a solution of coolant through the displacement of copper from solution in the basis metal is iron.

However, the practical application of this method showed that the resulting copper coating does not possess sufficiently high adhesion to the substrate, and this reduces the efficiency of the affected floor parts. In addition, this method requires exposure of a covered part of the surface-plastic deformation, which, in turn, presents certain difficulties in the practical implementation of the method and limits its use for coating workpieces of complex shape, small size or with holes or cavities.

The closest known is a method of forming a copper coating on the surface of steel products described in the patent of Russian Federation N 2110609 (published in BI N 13, 1998). By this method on the surface of steel cause the suspension of a powder of highly dispersed copper in the liquid containing CuCl2, colloidal graphite, ndimethylacetamide, urea, stearic acid, and water. Then this surface is subjected to intensive mechanical stress, namely surface-plastic deformation. In reoe coating with high adhesion to the surface.

This method allows to obtain a solid copper coating on the steel surface in the presence of intense mechanical action on the coated copper surface, which, moreover, must be carried out simultaneously with the chemical processes taking place on the coated surface, the interaction of this surface coated with a suspension of copper powder. The need for strong mechanical impact on covered copper steel surface due to the peculiarities of the chemical processes occurring during the interaction of the steel surface with reagents suspension of copper powder. The processes these are such that they do not provide strong adhesion with the surface formed therein a copper film and require mechanical hardening of the surface layer at the time of its formation.

The above-mentioned features of this method is not applicable for coating copper steel parts of complex shape, small or contains holes or cavities having a thin wall. Do not apply it in the field, because it requires a fairly complex of hardware.

The objective of this invention is to provide such a method which is are due to chemical effects on the surface of the substance, having a specific composition. But such copper coating should have high adhesion to the substrate and have the following positive operational features:

- the possibility of the formation of solid copper coatings on steel large size simple drawing on the surface of a substance of a particular composition,

- the possibility of the formation of solid copper coating of complex profile, with holes large length and small diameter, and the cavity of a complex configuration by simply immersing the part in a liquid substance of a particular composition;

- the possibility of the formation of solid copper coatings in the field, including at low temperatures (-2 - 0)oC;

- the exclusion of any external energy (mechanical, electrical, thermal) during formation of a solid copper coatings.

The problem is solved in that, as known, in this way, the surface of the metal or its alloys cause the suspension containing the copper powder and the acid solution chemical components.

In contrast to the known, in the present method, the acidic solution chemical componenet solution of the chemical components was adjusted to pH < 3 adding to this solution the necessary quantity of any of the strong acids, non-oxidizing with respect to copper ions, after which the coated copper surface is kept in a specified suspension for a specified time.

As the reductant in this way it is possible to use substances belonging to the class of carboxylic acids, in particular formic or acetic acid.

As the reductant in this way it is possible to use substances belonging to the class hydroxide nitrogen acidic compounds.

As the reductant in this way it is possible to use salts of multivalent metals in their lower oxidation States, in particular titanium salt of trivalent, divalent iron, and divalent tin.

As the reductant in this way it is possible to use substances belonging to the class of aldehydes, in particular formaldehyde, formaldoxime.

As the reductant in this way it is possible to use substances belonging to the class of polyhydric phenols, in particular, resorcinol, pyrocatechol, hydroquinone, pyragollole.

To regulate the pH environment of less than three in osposobe implemented the following mechanism for the formation of the copper coating.

Strongly acidic environment of the suspension (pH < 3) provides ion exchange between the solution of the suspension and copper powder and between this solution and the iron contained in a steel or iron surface. As a result, the boundary between the coated surface and covering her suspension occurs galvanic pair copper - iron". Thus copper in the galvanic couple has electrophoretically potential relative to the suspension medium, and the iron - electronegative. As a result, the system covered iron surface - suspension of copper" is the internal electrolysis and ion is the transfer of copper cations on iron surface with the formation of her copper layer. The selection of the conditions of this process of ion transfer (corresponding pH and reducing agent), you can implement an autocatalytic reaction mechanism of ion exchange with a continuous increase in the thickness of deposited film of copper on the iron surface.

The above process was first implemented in the present invention, and it allows you to fully, for the first time, to solve this technical problem, which gives grounds to speak about the presence izobretatelskikh pure copper in a quantity sufficient to this powder can cover the iron surface, which form a copper layer, is mixed with solution of any reducing agent, for example with an aqueous solution of acetic acid, belonging to the class of carboxylic acids. Measure the pH of the solution, and if it is higher than three, then add acetic acid until then, until the pH becomes less than three, for example, will be equal to two. The result is a suspension of copper powder in a very acidic reducing agent, such as acetic acid. In the resulting suspension is placed iron detail. Or the suspension applied to the surface of the iron details, such as its smear if it is thick enough, or poured on the surface. In this and in another case, the process goes equally well.

Present in a solution of acetic acid reacts with metallic copper, translating it into copper ions to form copper acetate, soluble in water. At the same time this acid reacts with the surface layer of iron, turning it into acetic acid iron, which is also soluble in water. However, due to the fact that copper ions are electrophoretically potential relative to the reaction medium, and acid to metallic copper, forming on the surface of the iron parts of the layer of pure copper, having high adhesion to coated with this layer of the surface.

While at pH values greater than three, the process does not go at all, because in this case the environment does not provide a translation of the atoms of iron and copper in ionic form. At pH 3 the process will go, but in the lowest degree, because as a result of what is happening in the environment reactions pH will quickly become more than three and to maintain the process in time with the high pH will need to constantly add acetic acid.

Example 2

Preparing an aqueous solution of hydrazine hydrochloric acid, which belongs to the class of nitrogen-containing hydroxide acid compounds and is a reducing agent with respect to copper ions. To this solution was added hydrochloric acid in a quantity sufficient to obtain a pH of the medium is equal to two (i.e., less than three). The obtained acidic solution of hydrazine hydrochloric acid is mixed with a metal powder of copper, and thus, the suspension. When the metallic copper powder charge in a quantity sufficient to cover, at least a thin layer, the entire metal surface to be coated with copper. After 10-15 minutes covered copper surface orocess deposition of a layer of metallic copper on the iron surface is the same as described in example 1. Only in this case the mutual exchange of ions of iron and copper has a different shape due to their interaction with hydrochloric acid, and recovery of copper ions on the iron surface is due to the reducing properties of hydrazine hydrochloric acid.

Example 3

Prepare a water solution of formaldehyde, which belongs to the class of aldehydes and is a reducing agent with respect to copper ions. To this solution was added sulfuric acid in a quantity sufficient to obtain a pH of the medium is equal to two (the pH value can be controlled by any known method, for example using a paper indicator). The obtained acidic solution is mixed with a metal powder of copper (as indicated in the previous examples) and receive a suspension of copper. This suspension is applied on the iron surface, maintained at this surface under suspension for 10-15 minutes, after which the suspension is removed from the surface. As a result, the iron surface is formed from solid copper film.

All processes in this example, occur as described in the above examples.

Example 4

Prepare a water solution of salt FeCl2in which iron is a polyvalent metal and fuck osstanavlivayuschie properties towards copper (Fe+3); so it is in this example a solution of a reducing agent. To a solution of FeCl2add sulfuric acid (H2SO4) in a quantity sufficient to obtain a pH of the medium is equal to two, after which it is mixed with copper powder and receive a suspension of copper. The resulting suspension of copper applied to the surface of steel (an alloy of iron), soak for 10-15 minutes, after which the suspension is removed from the surface on which the result is a durable copper film.

In all the above examples, the process of forming the copper film on the surface of iron and its alloys (steel, cast iron) takes place at temperatures from 0 to 90oC. the adhesion of the copper film to the iron surface was determined by various standard methods: method of polishing method kravanja, the method of winding, the method dice scratches, the method of bending the substrate by a chemical method of saturation of the copper coating by atomic hydrogen. In all of these methods were not observed peeling off the iron surface of the copper coating, indicating a high degree of adhesion of the copper coating to the iron surface.

1. The method of forming a copper coating on the surface of iron or its alloy is Astor chemical components, characterized in that, as the chemical components of the acidic solution contains a solution of a substance, which is a reducing agent with respect to copper ions, and the acidity of the solution specified substance was adjusted to pH < 3 adding to this solution the required amount of a strong acid, non-oxidizing with respect to copper ions, after which the surface of iron or its alloys can withstand this suspension to the formation of the copper film of the desired thickness.

2. The method of forming a copper coating on p. 1, characterized in that it as a strong acid, the addition of which increase the acidity of the solution to pH < 3, use sulfuric or hydrochloric acid.

3. The method of forming a copper coating on p. 1, characterized in that the acid solution chemical components introduce some of the carboxylic acid.

4. The method of forming a copper coating on p. 3, characterized in that the acid solution chemical components enter formic or acetic acid.

5. The method of forming a copper coating on p. 1, characterized in that as a substance, which is a reducing agent with respect to copper ions in acidic solution chemical components enter the city of the tives such as those as a hydroxide nitrate compounds in acid solution chemical components injected hydrazine sulfate, hydrazine hydrochloric acid, hydroxylamine hydrochloric acid or hydroxylamine sulfate.

7. The method of forming a copper coating on p. 1, characterized in that as a substance, which is a reducing agent with respect to copper ions in acidic solution chemical components enter any of the aldehydes.

8. The method of forming a copper coating on p. 7, characterized in that the quality of some of the aldehydes in acidic solution chemical components injected formaldehyde or formaldoxime.

9. The method of forming a copper coating on p. 1, characterized in that it as a substance, which is a reducing agent with respect to copper ions in acidic solution chemical components enter any of polyhydric phenols.

10. The method of forming a copper coating on p. 9, characterized in that as some of the polyhydric phenol in acidic solution chemical components enter resorcinol, pyrocatechol, hydroquinone or pyragollole.

11. The method of forming a copper coating on p. 1, characterized in that in it the image quality is impressive injected soluble salt of any of multivalent metals in their lower oxidation States.

12. The method of forming a copper coating on p. 11, characterized in that salts of any of the polyvalent metals in their lower degree of oxidation in acid solution chemical components injected soluble titanium salt of trivalent, divalent iron or divalent tin.

 

Same patents:

The invention relates to a chemical magnesiu dielectrics and can be used in automotive, engineering and instrument-making industry and in the production of household appliances

FIELD: technological processes.

SUBSTANCE: invention is related to technology for production of metalised woven and nonwoven materials, and may be used for production of catalysts, and also for production of decorative and finishing materials. Method includes previous chemical activation of coated material surface, using as activator glyoxal acid and/or oxalic acid. Then chemical metallisation is carried out, which is realised from solution containing bluestone. Stabiliser used is tetraethylene glycol, and reducer - glyoxal. Sodium hydroxide is used in solution to maintain required acidity.

EFFECT: invention provides for production of metalised dispersed woven and nonwoven materials using simplified technology, with simultaneous cheapening and provision of production safety due to use of proposed ingredients and their certain ratio.

2 ex

Up!