US2690983A - Process of removing rust and inhibiting further rusting - Google Patents

Description

Patented Oct. 5, 1954 UNITED STATES ATENT OFFICE PROCESS OF REMOVING RUST AND INHIBITING FURTHER RUSTING The Kromite Products Company, Bedford,

Ohio, a corporation of Ohio No Drawing. Application April 23, 1952, Serial No. 283,980

2 Claims.

The plating of ferrous surfaces with chromium and the like for finish and prevention of rust is universal. However, even with this there is a tendency for iron rust stain to appear in the course of time, and this tendency is greatly increased in the case of automobiles by the prevalent use of salt and calcium chloride as snowmelting material on streets. In accordance with the present invention, rust stains on plated surfaces may be removed, and by material which also inhibits recurrence. Excessive polishing and wear for maintaining desired appearance of plated surfaces thus becomes unnecessary, and with increase in longevity of the plate coat. Other objects and advantages will appear from the following description.

To the accomplishment of the foregoing and related ends, said invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

We have found that by subjecting plated surfaces which are rust-stained, to treatment with material as further detailed below, the rust is removed, and at the same time the surface receives a protection which prevents ready recurrence of staining. We have found that polycalcium compounds, particularly polycalcium silicate if properl applied to a rust-stained surface, such as of chromium plating, readily clears such. Tricalcium silicate is particularly contemplated. With this there may be a component of dicalcium silicate, and of tricalcium aluminate. Compositions containing tricalcium silicate and tricalcium aluminate are hereinafter concisely termed polycalcium silicate and aluminate. Such material in finely powdered form is applied to the rust stained surface in the presence of water, and it is important that a time interval be allowed between the bringing together of the material and the water, sufficient to allow action therebetween, before the material is applied to the plated surface. Thus, in preferred procedure, an applying fabric is wet with Water, not in excess, and the powder is dusted or poured on the wet fabric. This is allowed to stand for some moments, approximately a minute. Then, such surface is rubbed onto the rust-stained plating lightly, and the rust clears off, and the plating is then immediately wiped dry. The nature and reason for the action is obscure and not definitely known,

and we are not bound by any theory, but there is reason to believe that in the presence of the moistening water the tricalcium silicate goes over into monocalcium silicate and calcium hydroxide. The latter is higher in the E. M. F. scale, and is able to affect the iron oxide or rust. The minute holes through the plate coat, by which the permeation and oxidation of the iron base occurred, are apparently then filled and sealed oif by the by-products of the residue. Irrespective of any attempted theorization however, the practical fact is that badly rust-stained surfaces as of chromium plate are quickly cleared, and the surprising further effect is that the bright appearance persists, rather than soon requiring additional polishing.

Polycalcium aluminate has effective action to a lesser extent than the aforementioned silicates, and may be used in conjunction therewith. A combination of tricalcium silicate, dicalcium silicate and tricalcium aluminate, powdered, is of practical utility, and it is possible to provide such without excessive preparation cost by making use of the materials available on the market. Tricalcium silicate and dicalcium silicate, with or without tricalcium aluminate can be prepared as in known manner by heating limestone and clay in intimate mixture, to a temperature providing incipient fusion or sintering, the raw materials being preliminarily ground and slurried, and then fired, and finally ground to desired mesh. This should be on the order of 200 mesh or finer. Limestone and clay ground and slurried and burned as on the order of Portland cement also provides an approximation. In general, if calcium aluminate in addition to the polycalcium silicates is desired, such a composition may have a ratio CaO The ratio of silica and alumina may be in such material between about 2.5 and 4. In any event, tricalcium silicate is contemplated particularly, and the other compounds as stated may be additional. Impurities such as iron oxide, magnesium oxide, etc., should be absent or minimal, not exceeding a few percent.

The line powdered treating agent, as aboveindicated, in any case is to be applied to the surface to be treated, by first allowing a few moments time for action with the moistening water preliminarily. And, such time should not be excessive, as the efliciency of results then may be lessened.

As an example: A wiping cloth, as for instance customary cheese-cloth, is wet with water and dripping-excess removed, and powdered tricalcium silicate, with which may be dicalcium silicate and tricalcium aluminate, is applied in layer which can be well wet by the water carried by the fabric. The Water is allowed to act for a few moments up to about a minute, and then the ruststained automobile bumper or the like to be cleaned is lightly rubbed with such fabric for removal of the rust. The surface is wiped dry, and nascently-formed hydrated silica residue, and alumina if present, fills and seals pervious pinholes in the plate coat.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

We therefore particularly point out and distinctly claim as our invention:

1. In a process of treating plated metal surfaces, eliminating rust from a chromium-plated surface on an iron base by applying moistening Water and a small amount of polycalcium silicate and aluminate powder to a fabric, allowing action between the moistening water and powder for a few moments, then lightly rubbing such fabric on the rust-affected iron base chromium plated metal surface, and wiping dry.

2. In a process of treating metal surfaces, eliminating rust from a chromium-plated surface on an iron base by wetting a fabric, applying thereto a powder of polycalcium silicates and aluminate, allowing action between the moistening water and powder for a few moments, then lightly rubbing such fabric on the rust-affected iron base chromium plated metal surface, and wiping dry.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,143,614 Criswell June 22, 1915 1,526,149 Jackson Feb. 10, 1925 1,729,765 Dinley Oct. 1, 1929 2,403,821 Morgan July 9, 1946 OTHER REFERENCES Partington: Textbook of Inorganic Chemistry, 6th ed., 1950; pub. McMillan and Co., London, page I60. Copy Scientific Library.

Claims (1)

1. IN A PROCESS OF TREATING PLATED METAL SURFACES, ELIMINATING RUST FROM A CHROMIUM-PLATED SURFACE ON AN IRON BASE BY APPLYING MOISTENING WATER AND A SMALL AMOUNT OF POLYCALCIUM SILICATE AND ALUMINATE POWDER TO A FABRIC, ALLOWING ACTION BETWEEN THE MOISTENING WATER AND POWDER FOR A FEW MOMENTS, THEN LIGHTLY RUBBING SUCH FABRIC ON THE RUST-AFFECTED IRON BASE CHROMIUM PLATED METAL SURFACE, AND WIPING DRY.