GB2069538A

GB2069538A - Phosphate Composition for the Treatment of Oxidized Ferrous Metals

Info

Publication number: GB2069538A
Application number: GB8002696A
Authority: GB
Original assignee: Urzay D M
Current assignee: Urzay D M
Priority date: 1980-01-26
Filing date: 1980-01-26
Publication date: 1981-08-26
Also published as: GB2069538B

Abstract

A composition for the treatment of oxidized ferrous metals which have to be painted afterwards a mixture of phosphoric acid and a solution of copper sulphate, and may include a sufficient quantity of barium to precipitate the sulphate ions. Lamp black, silicon gel and a thickening agent may also be included.

Description

SPECIFICATION Product for the Treatment of Oxidized Ferrous Metals The subject of the present invention is a new product for the treatment of oxidized ferrous metals which have to be painted afterwards.

The processes known up to now for removing oxide from ferrous metals, such as mechanical processes like sand or metal shot blasting and chemical etching by immersion in a strong acid solution, such as hydrochloric or sulphuric acid, which are widely used, clean the iron efficiently, but they have the disadvantage of leaving it very susceptible to further oxidation, and because of this it must be painted without delay.

In addition one must take into account the fact that a large number of these treatments must be carried out "in situ" and this makes it imposssible to use either blasting or immersion. In these cases, manual cleaning or mechanical brushing methods are usually used, which do not remove the oxide in a satisfactory manner. To this disadvantage we must add the high cost and the impossibility of using such methods on parts which are sometimes inaccessible.

There are also numerous specifications which specify the preparation of products for removing oxide of hydrochloric acid, phosphoric acid, sodium hydroxide, etc. with various embodiments for their application by spraying, brush immersion or also as a paste. The use of these preparations makes it necessary for the iron to be washed immediately after deoxidation and before painting. For this reason, these preparations are only carrying out a cleaning operation without reinforcing the protection of the material treated.

The subject of this invention relates to the preparation of products for the removal of the oxide from oxidized ferrous materials which then have to be painted.

This product, according to the invention is basically made up of a mixture of phospheric acid and a solution of copper sulphate.

Thus the product incorporates a significant percentage of copper salts and numerous experiments carried out personally by the applicant have proved the great increase in efficiency produced by the salts in the treatment for the deoxidation and protection of iron.

The oxide is reduced by the acid, the copper ions increase the speed of phosphotisation of the iron and are deposited in metallic form on the clean areas, thus protecting them.

When introducing the copper salts in the form of copper sulphate into the formula for this new preparation, it is advisable to eliminate the sulphate ions by adding an equivalent quantity of barium ions which lead to the formation of barium sulphate, a pigment which also increases the protection of the iron.

We can also add small quantities of lamp black, powdered silicon gel for its thixotropic qualities and a thickening agent to give the required viscosity.

Thus we have a very efficient product for the treatment of oxidized iron before it is painted.

This new product is applied in the following way: The oxidized iron if first of all brushed with a metal brush to remove large particles and any surplus oxide. Then our product is applied, which may be done either with a brush or a spray gun and, once this application is dry, the iron is deoxidized, passivated and in an excellent condition to receive the paint, red lead and finishing paints. It is better for the whole surface of the iron to be oxidized, avoiding excess, before applying our product. If any part is not oxidized the product will take a long time to dry, but this can be solved by rubbing with a cloth to remove the surplus product before painting.

The following could be used as a practical embodiment of the formula:- Phosphoric acid H3PO4 (75% solution) 55 Copper sulphate CuSo4. 5H20 (20% Solution) 40 Water H20 5 Barium hydroxide Ba (OH)2 8H2O 10'1 mixing the constituents in the order indicated, adding the barium hydroxide at the end and stirring to produce an intimate mixture with precipitation of all the sulphate ions.

The following may also be added: Lamp black 0'5 Silicon gel 1 thickening agent (cellosize) 0'1

Claims 1. Product for the treatment of oxidized ferrous metals which afterwards have to be painted, in which the product is made up of a mixture of phosphoric acid and a copper sulphate solution.

2. Product according to Claim 1, in which the mixture includes a sufficient quantity of barium to precipitate the sulphate ions.

3. Product according to Claim 1 or Claim 2, in which the mixture includes 55 parts of 75% phosporic acid, 40 parts of a 20% solution of copper sulphate, and 5 parts of water, to which has been added a sufficient quantity of barium to precipitate the sulphate ions.

4. Product according to any preceding claim, in which the product also contains small quantities of lamp black, silicon gel and a thickening agent.

5. Product according to any preceding claim, in which the product is applied after prior brushing to eliminate excess oxide, by a brush or by spraying with a gun.

6. Product for the treatment of oxidized ferrous metals which afterwards have to be painted substantially as described herein.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Product for the Treatment of Oxidized Ferrous Metals The subject of the present invention is a new product for the treatment of oxidized ferrous metals which have to be painted afterwards. The processes known up to now for removing oxide from ferrous metals, such as mechanical processes like sand or metal shot blasting and chemical etching by immersion in a strong acid solution, such as hydrochloric or sulphuric acid, which are widely used, clean the iron efficiently, but they have the disadvantage of leaving it very susceptible to further oxidation, and because of this it must be painted without delay. In addition one must take into account the fact that a large number of these treatments must be carried out "in situ" and this makes it imposssible to use either blasting or immersion. In these cases, manual cleaning or mechanical brushing methods are usually used, which do not remove the oxide in a satisfactory manner. To this disadvantage we must add the high cost and the impossibility of using such methods on parts which are sometimes inaccessible. There are also numerous specifications which specify the preparation of products for removing oxide of hydrochloric acid, phosphoric acid, sodium hydroxide, etc. with various embodiments for their application by spraying, brush immersion or also as a paste. The use of these preparations makes it necessary for the iron to be washed immediately after deoxidation and before painting. For this reason, these preparations are only carrying out a cleaning operation without reinforcing the protection of the material treated. The subject of this invention relates to the preparation of products for the removal of the oxide from oxidized ferrous materials which then have to be painted. This product, according to the invention is basically made up of a mixture of phospheric acid and a solution of copper sulphate. Thus the product incorporates a significant percentage of copper salts and numerous experiments carried out personally by the applicant have proved the great increase in efficiency produced by the salts in the treatment for the deoxidation and protection of iron. The oxide is reduced by the acid, the copper ions increase the speed of phosphotisation of the iron and are deposited in metallic form on the clean areas, thus protecting them. When introducing the copper salts in the form of copper sulphate into the formula for this new preparation, it is advisable to eliminate the sulphate ions by adding an equivalent quantity of barium ions which lead to the formation of barium sulphate, a pigment which also increases the protection of the iron. We can also add small quantities of lamp black, powdered silicon gel for its thixotropic qualities and a thickening agent to give the required viscosity. Thus we have a very efficient product for the treatment of oxidized iron before it is painted. This new product is applied in the following way: The oxidized iron if first of all brushed with a metal brush to remove large particles and any surplus oxide. Then our product is applied, which may be done either with a brush or a spray gun and, once this application is dry, the iron is deoxidized, passivated and in an excellent condition to receive the paint, red lead and finishing paints. It is better for the whole surface of the iron to be oxidized, avoiding excess, before applying our product. If any part is not oxidized the product will take a long time to dry, but this can be solved by rubbing with a cloth to remove the surplus product before painting. The following could be used as a practical embodiment of the formula:- Phosphoric acid H3PO4 (75% solution) 55 Copper sulphate CuSo4. 5H20 (20% Solution) 40 Water H20 5 Barium hydroxide Ba (OH)2 8H2O 10'1 mixing the constituents in the order indicated, adding the barium hydroxide at the end and stirring to produce an intimate mixture with precipitation of all the sulphate ions. The following may also be added: Lamp black 0'5 Silicon gel 1 thickening agent (cellosize) 0'1 Claims

1. Product for the treatment of oxidized ferrous metals which afterwards have to be painted, in which the product is made up of a mixture of phosphoric acid and a copper sulphate solution.

5. Product for the treatment of oxidized ferrous metals which afterwards have to be painted substantially as described herein.

New claims filed on 1 5.4.81 New or Amended Claims:-

1. Product for the treatment of oxidized ferrous metals which afterwards have to be painted, in which the product is made up of a mixture of phosphoric acid and a copper sulphate solution, and the mixture includes a sufficient quantity of barium to precipitate the sulphate ions.

2. Product according to Claim 1, in which the mixture includes 55 parts of 75% phosphoric acid, 40 parts of a 20% solution of copper sulphate, and 5 parts of water, to which has been added a sufficient quantity of barium to precipitate the sulphate ions.

3. Product according to Claim 1 or Claim 2, in which the product also contains small quantities of lamp black silicon gel and a thickening agent.

4. Product according to any preceding claim, in which the product is applied after prior brushing to eliminate excess oxide, by a brush or by spraying with a gun.