A Process of and Means for Protecting Iron, Steel, and like Materials from Rust.
Year: 1895

page_text: Date of Application, 25th Feb., 1895
Comple'e Specification Left, 23rd Nov., 1895-Accepted, 25th Jan., 1896
PROVISIONAL SPECIFICATION.
[Communicated from abroad by THE FARBENFABRIKEN, vormals FRIEDRICH
BAYER & Co., of Elberfeld, Germany.]
A Process of and Means for Protecting Iron, Steel, and like
Materials from Rust.
I HENRY EDWARD NEWTON of The Office for Patents, 6 Bream's Buildings,
Chancery Lane in the County of London, Patent Agent, do hereby declare the
nature of this invention to be as follows:-
The present invention relates to a process of and means for protecting iron,
steel, and like materials from rust.
The process in general consists in coating the surface of iron, steel, or other
metal, in an unwrought or wrought state, with a solution in water of hydroferro-
cyanic acid, or hydroferricyanic acid, or a mixture thereof, most advantageously in
admixture with any strong acid.
A previous preparation of the metallic surface is not necessary.
The means used for preventing the formation of rust on the iron or other
surface, viz., the solutions in water of hydroferrocyanic acid or hydroferricyanic
acid, or a mixture thereof, with or without the addition of any strong acid, form
on the metallic surfaces treated a coating which consists of the iron double salts
formed, and which perfectly prevents the said materials from rusting.
According to the researches of my foreign correspondents, it is advantageous
to use a dilute watery cold solution of hydroferrocyanic acid or hydroferricyanic
acid, or a mixture thereof, with or without the addition of any strong acid. The
coating thus produced on the surface can be covered with any suitable paint or paints,
such as oil colors, or with any other suitable material. The means hereinbefore
defined may also be employed together with other materials producing the same or
a similar effect.
The new process above referred to materially differs from the knowu process,
which consists in treating iron with potassium ferrocyanide and ferric chloride,
for the iron thus treated acquires merely a blue color, without preventing the
formation of rust. It is known that ferrocyanides in watery solutions are acted on
by ferric chloride, blue colored precipitates (such as Turnbull's blue, Prussian
blue, or the like) being formed, and the researches of my foreign correspondents
have shown that on treating iron in the above mentioned manner with potassium
ferrocyanide and ferric chloride, the said blue insoluble and pulverulent percipitates,
adhere but loosely to the surface of the materials, and never form an air and
waterproof coating, whereas, according to the present invention, an air and water-
proof coating results, on using the free hydroferro- or hydroferricyanic acid, which
intimately combine with the iron or the like, so-called double salts being formed.
which adhere strongly and cannot be rubbed off.
According to the researches of my foreign correspondents, it is also not necessary
to free previously from rust the iron or the like materials to be treated in the new
manner hereinbefore defined, but the said solutions of hydroferro- or hydroferri-

page_text: cyanic acid can be brushed at once on the said materials, a further spreading of
the rust being thus prevented.
Dahi orth C
NEWTON & SON,
Agents for the Applicant.
A Process of and Means for Protecting Iron, Steel, and like
Materials from Rust.
I HENRY EDWARD NEWTON of The Office for Patents, 6 Bream's Buildings,
Chancery Lane in the County of London, Patent Agent, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
The present invention relates to a process of and means for protecting iron,
steel, and like materials from rust.
The process, speaking generally, consists in coating the surface of iron, steel, or
other metal, in an unwrought or wrought state, with a solution of hydroferrocyanic
acid, or hydroferricyanic acid, or a mixture thereof, most advantageously in
admixture with strong acid.
A previous preparation of the metallic surface is not necessary.
The means used of preventing the formation of rust on iron or other surface,
viz., the solution of hydroferrocyanic acid, or hydroferricyanic acid, or a mixture
thereof, together with a strong acid, if desirable, form on the metallic surface which
is treated, a coating consisting of iron double salts, which perfectly prevents the said
materials from rusting.
According to the researches of my foreign correspondents, it is advantageous to
use, for instance, a dilute cold solution in water of hydroferrocyanic acid or hydro-
ferricyanic acid, or a mixture thereof, to which, if necessary, a strong acid is
added. The coating produced on the surface of the metal can be covered with
any suitable paint or paints, such as oil colors, or with any other suitable materials.
The means herein before defined may also be used together with other materials
producing the same or a similar effect.
The new process above referred to, is materially different from the known
process, which consists in treating iron with potassium ferrocyanide and ferric
chloride, as the iron thus treated merely acquires a blue color, without the formation
of rust being prevented. It is well known that solutions of ferrocyanides are acted
on by ferric chloride, blue colored precipitates (such as Turnbull's blue, Prussian
blue, or the like) being formed, but my foreign correspondents find that, on treating
iron with such salts, the blue insoluble and pulverulent substances which are
formed adhere but loosely to the surface of the materials, and never form an
air and waterproof coating, whereas, according to the present invention, an air-
and waterproof coating is produced on using free hydroferro or hydroferricyanic
acid, which intimately combine with the iron, or the like, so-called double salts
being formed, which adhere strongly and cannot be rubbed off.
According to my foreign correspondents, it is also not necessary to previously
remove rust from the iron, or the like materials to be treated in the new manner
hereinbefore defined, but the said solutions of hydroferro- or hydroferricyanic
acid can be brushed at once over the said materials, a further spreading of the
rust being thus prevented.
The solutions of hydroferro- or hydroferri-cyanic acid, or mixtures thereof, can
be obtained by decomposing concentrated solutions of salts of the said acids
with the aid of any mineral acids, filtering off the so-formed precipitates, and
adding thereto such a quantity of water that the so-formed liquids contain from

page_text: about 10 to 25 per cent. of hydroferro- or hydroterricyanic acid, or a mixture.
thereof.
If the said precipitates are not washed with water, a small proportion of the
mineral acid used for precipitation remains therein. This small quantity of
mineral acid (being from about to per cent. of the hydroferro or hydroferri-
cyanic acid, or the mixture thereof) suffices to increase the action.
Naturally, on using the precipitates when previously washed with water in order
to remove the adherent part of the mineral acid used for precipitation, any mineral
acid may be subsequently added, if desirable, to the solutions of hydroferro- or
hydroferricyanic acid, or mixtures thereof.
The quantity of the mineral acid to be added may be from about to per cent...
of the hydroferro- or hydroferri-cyanic acid, or the mixture thereof.
Naturally, in practically carrying out the present invention, many mo lifications.
can be made. Thus, for instance, instead of aqueous solutions of hydroferro or
hydroferricyanic acid, solutions of these substances in wood-spirit, alcohol, or the
like, can be used, or solutions thereof in aqueous wood-spirit, aqueous alcohol,
or the like, can be used, adding, if desirable, in either case, any suitable oil, varnish,
or the like. If solutions in wood-spirit, alcohol, or the like, are used, the formation.
of the coating on the metallic surface proceeds more slowly than when aqueous or
aqueous-alcoholic solutions are used, but the coating thus formed is more uniform.
It is also noteworthy, that solutions containing hydroferro or hydroferricyanic.
acid, or a mixture thereof, together with wood-spirit, alcohol, or the like, cau be
more readily distributed over the surface to be coated.
My foreign correspondents find that it is very advantageous to use solutions.
containing bydroferro- or hydroferri-cyanic acid, or a mixture thereof, and wood-.
spirit or alcohol, or the like, together with any suitable varnish or oil, or the like.
In practice, my foreign correspondents propose to use, for instance, solutions
containing 1 part of hydroferro- or hydro-ferricyanic acid, or a mixture thereof,
together with part of wood-spirit or alcohol, or the like, and from 2 to 3 parts
of oil, varnish, or the like. Naturally, the proportions of these or the like.
ingredients can be varied within certain limits, without altering thereby the nature.
of the present invention, which, speaking generally, relates to a process of and
means for protecting iron, steel, and like materials from rust, and which is based
on the action of hydro-ferro and bydroferricyanic acid on the said metallic.
materials.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed (as communicated to me
from abroad), I declare that what I claim is :-
--
1. The process for protecting iron, steel, and like materials, in an unwrought
or wrought state, from rust, by the application to them of solutions of hydro-.
ferro or hydroferricyanic acid, or of a mixture of these two solutions.
2. In the process defined by the foregoing claim:-(a) the use of aqueous
solutions containing hydroferro or hydroferricyanic acid, or a mixture thereof, and,.
if desirable, a strong acid; and (b) the use of solutions of hydroferro or hydro-
ferricyanic acid, or a mixture thereof, in wood spirit, alcohol, or the like, or in
aqueous wood spirit or alcohol, or the like, adding oils, varnishes, or the like, or
Lot, as may be desirable.
3. The process for protecting iron, steel, and the like materials, from rust, which
process consists either (a) in coating the surface of iron, steel, and like metallic
materials, with an aqueous solution containing hydroferro or hydroferricyanic acil,
or a mixture thereof, with or without a strong acid; or (b) in coating the surface
of iron, steel, and like metallic materials, with solutions containing hydroferro or
hydroferricyanic acid, or a mixture thereof, and wood spirit, alcohol, or the like,.
with or without oils, varnishes, or the like.
4. As product of manufacture, a means adapted for protecting iron, steel, and
like materials from rust, and containing hydroferro or hydroferricyanic acid, or a.

page_text: mixture thereof, together with other substances capable of facilitating the
formation of air- and waterproof coatings on metallic surfaces.
Dated this 14th day of November 1895.
NEWTON & SON,
Agents for the Applicant.