IMPROVEMENTS IN COATING METALS WITH ONE OR SEVERAL OTHER METALS, AND IN OXYDIZING THE SURFACE OF THESE LATTER
Year: 1864

page_text: LETTERS PATENT to Frederic Weil, of Paris, France, Civil Engineer,
for the Invention of "IMPROVEMENTS IN COATING METALS WITH ONE OR
SEVERAL OTHER METALS, AND IN OXYDIZING THE SURFACE OF THESE LATTER."
Sealed the 8th August 1864, and dated the 29th February 1864.
PROVISIONAL SPECIFICATION left by the said Frederic Weil at the
Office of the Commissioners of Patents, with his Petition, on the
29th February 1864.
I, FREDERIO WEIL, of Paris, France, Civil Engineer, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN COATING METALS WITH
ONE OR SEVERAL OTHER METALS, AND IN OXYDIZING THE SURFACE OF THESE LATTER,"
to be as follows:-
The object of these improvements is providing metals by means of dipping
or immersion in a suitable bath or baths, with either, 1ly, an adhering
coating or coatings of one or several other metals, and thus produce the
coppering, silvering, and so on of lead, zinc, antimony, platinum, or of suitable
alloys of them, or of cast or wrought iron, steel, or other metals; or, 2ly, with
an adhering coating of another metal or metals, partly oxidized at the surface
for producing an effect of bronzing or colouring in various shades of the said
metals or metallic alloys, such for instance as lead, zinc, wrought or cast iron,
[Price 8d.1

page_text: steel, antimony, platinum,as well as ordinary bronze,by immersion or dipping
in suitable solutions. By the hitherto known means of coating metals with
another metal or metals, the adherence between the superposed metal was
not sufficiently intense for many purposes. My processes allow of obtaining
the coppering, silvering, and so on of lead, zinc, antimony, or of alloys of
these metals, of wrought or cast iron, steel, and other metals, by dipping or
immersion if required in cold alkaline baths or solutions, whilst the coating
thereby obtained is perfectly adhering, and may at pleasure be obtained
either with a brilliant or a dead appearance.
The metals to be coated, after having been first perfectly cleaned from
scale or grease, are to be treated in the following manner :-
§ 1. The first part of my Invention relates to a process for providing with
a coating of copper (or what may be called coppering) lead, zinc, antimony,
platinum, or other metals, or the alloys of lead, zinc, or other metals, by
dipping or immersing the same for a sufficient length of time in an alkaline
aqueous solution of a salt of copper containing also tartaric acid, viz., aqueous
alkaline solutions of double tartrates of copper,and an alkali,such for instance,
as sulphate of copper dissolved in a solution of the double tartrate of potash
and soda (salt of seignette) made strongly alkaline by the addition for
instance of caustic soda. The tartaric acid might be replaced by racemic acid
or other suitable organic matter having the effect of preventing the oxide of
copper from forming a precipitate by the addition of a fixed alkali. The solu-
tion might be made alkaline by means of soda, ammonia, or potash, and be
more or less diluted with water according as required, and the same may be
prepared, for instance, by dissolving the salt of copper in a suitable quantity
of water, to which is then added the tartaric salt, dissolved in an alkaline ley,
say, for instance, in soda ley. The bath thus obtained may be further diluted
with water to the required strength according to the effects to be obtained.
What forms the conspicuous or main feature of this part of my Invention
is the making use of an alkaline solution for coppering metals, in this manner
a solution of any salt of copper in liquor ammoniac may serve for coppering
by simple immersion pickled or cleansed zinc.
§2. The next part of my Invention relates to the bronzing and colouring in
various shades of the surfaces of zinc,lead, platinum,antimony, or other metals
previously coppered by the process indicated in § 1. For this purpose baths
similar to those indicated in the said§for coppering are made use of, but which
are to contain much less of the salt of copper, and consequently, in the same
ratio, so much the more caustic alkali and alkaline tartrate; by immersing
the coppered articles in such solutions, a slight coppering and so on after the

page_text: bronzing or colouring of the surface to the required shade takes place. The
solutions may be used in the cold or in the heated state, and be more or less
concentrated according to the effects to be obtained. Instead of the tar-
trates, salts formed by other organic acids may be made use of. The bronzing
or colouring thus obtained I attribute to a partial oxidation of the surface
of the thin coating deposited on the already previously coppered articles,
and I consequently call this part of the process a partial oxidation of the
surface of the metallic coating. Zinced iron (or what is commonly denomi-
nated galvanized iron) or leaded iron may also be coppered by immersion
in the above mentioned solutions, but tin plate forms an exception, the tin
of this latter becoming dissolved in the solution, whilst the copper is pre-
cipitated in the state of protoxide of this metal.
3. The next part of my Invention relates to the coppering, bronzing, or
colouring in various shades or colours of wrought or cast iron, steel, and
other metals. For obtaining the said effects by the above mentioned baths
or solutions, the metals to be coated, bronzed, or coloured, are whilst
immersed in the solution kept in contact with metallic zinc; probably a
galvanic action hereby takes place, and it is likely, consequently, that the
zinc metal may be replaced by other metals or bodies acting in a similar
manner. The solutions may be made use of in the cold or warm state, the
length of time of immersion, the strength of the solutions, and their more
or less alkalinity be varied accordingly as found requisite. In replacing the
caustic alkali of the solutions by a bi-carbonate, the bi-carbonate of soda,
for instance, a solution decomposable by iron is obtained, the copper is pre-
cipitated in the state of protoxide, only a very thin film or coating of copper
is precipitated on the iron, and soon after the colouring or oxidation takes
place whilst if the metal to be coated be kept in contact with metallic zinc
the same result is obtained more rapidly.
§4. The next part of my Invention relates to the bronzing and colouring
of the various bronze alloys, brass, and other alloys. This I effect by
immersing bronze or other alloys in alkaline cupreous tartrate solution
described in § 1.
§ 5. The next part of my Invention relates to the silvering of copper,
wrought or cast iron, steel, or other metals, and also of zinc, lead, antimony,
wrought or cast iron, and other metals previously coppered by my processes.
For these purposes may be used an alkaline bath formed of an aquous solution
of nitrate of silver, tartaric acid, and an excess of ammonia, to which solution
is added a small quantity of cyanide of potassium, but any salt of silver may
serve for the purpose, and instead of the tartaric acid any other matter

page_text: exercising the same effect may be substituted. This bath or solution is
particularly applicable for silvering lead previously coppered by my pro-
cesses, zinc, coppered zinc, wrought or cast iron, and steel coppered by my
processes may also be silvered by immersion in an aqueous alkaline solution
of the nitrate or the chloride or silver in an excess of cyanide of potassium
or other alkaline cyanide. The solutions or baths may be more or less
diluted with water, any salt of silver be made use of, the ammonia replaced
by other suitable alkalies, and the tartaric acid, by other matters exercising
an effect similar to this acid, whilst only a comparatively small quantity of
an alkaline cyanide is required, viz., so much only as will prevent the
precipitating of the silver.
§6. The next part of my Invention relates to the silvering of wrought or
cast iron, steel, and other metals, not previously provided with a coating of
copper by my processes. By means of the solutions or baths indicated in
§ 5, the silvering of the just-mentioned metals may be obtained at once by
keeping the metal to be silvered in immediate contact with metallic zinc or
with any other body exercising a similar effect.
I wish to add here that in the various processes above described the coating
or coatings may be obtained, 1ly, by simple immersions or dipping in one of
the baths or solutions, the general composition of which has been indicated;
or 2ly, the effect of this immersion or dipping may be increased by either
keeping the metal in the bath in immediate contact with metallic zinc or any
other body exercising a similar effect; or, 3ly, by the aid of a galvanic battery.
My Invention is also applicable for obtaining galvano-plastic effects, and
various successive layers or coatings of different metals may be applied, whilst
if wished a partial oxidation or colouring, or bronzing in various shades be
obtained by it.
The principles on which are based the various processes ahove described
for coating by simple immersion or dipping a metal with one or more other
metals are that the metal to be coated be in presence, lly, of a solution
capable of dissolving the oxide of the said metal to be coated; 2ly, of a
solution of the metal which is to form the coating; 3ly, of a liquid, which
may be called the vehicle of the metallic oxide, or of the metal to be
dissolved, and which liquid is to act at the same time as a reductive
deoxidising or anti-precipitating agent; 4ly, of a solution prepared for the
purpose that the metal should be precipitated only on the metal to be coated
in a perfect adhering and not in the powdered state.
By my processes and according to the principles above described metals
may be coated with nickel, gold, antimony, zinc, or other metals for obtaining

page_text: for instance a coating of antimony, an alkalinized solution of tartar emetic
(tartrate of potash and antimony), either aloue or with the aid of metallic
zinc, may be used for certain metals, such as iron for instance.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Frederic Weil in the Great Seal Patent Office on the
29th August 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERIC
WEIL, of Paris, France, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-ninth day of February, in the year of our
Lord One thousand eight hundred and sixty-four, in the twenty-seventh year
of Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Frederic Weil, Her special licence that I, the said Frederic
Weil, my executors, administrators, and assigns, or such others as
I, the said Frederic Weil, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and at all
times thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN COATING METALS, WITH ONE OR SEVERAL OTHER METALS,
AND IN OXYDIZING THE SURFACE OF THESE LATTER," upon the condition (amongst
others) that I, the said Frederic Weil, my executors or administrators,
by an instrument in writing under my, or their, or one of their hands and
seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and cause
the same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE that I, the said Frederic Weil, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:
The object of these improvements is to provide metals by means of dipping
or immersion in a suitable bath or baths with either, lly, an adhering
coating or coatings of one or several other metals, and thus produce the
coppering, silvering, and so on of lead, zinc,antimony, platinum,or of suitable
alloys of these metals, or of cast or wrought iron, steel, or other metals; or

page_text: 2ly, an adhering coating of another metal or metals partly oxydized at the
surface for producing an effect of bronzing or colouring in various shades of
the said metals or metallic alloys, such for instance as lead, zinc, wrought or
cast iron, steel, antimony, platinum, as well as ordinary bronze, by immersion
or dipping in suitable solutions or baths.
By the hitherto known means of coating metals with another metal or
metals the adherence between the superposed metals was not sufficiently
intense for many purposes. My processes allow of obtaining the coppering,
silvering, and so on of lead, zinc, antimony, or of alloys of these metals, of
wrought or cast iron, steel, and other metals by dipping or immersion, if
required,in cold alkaline baths or solutions, whilst the coating thereby obtained
is perfectly adhering and may at pleasure be obtained either with a brilliant
or a dead appearance.
The metals to be coated, after having been first perfectly cleaned from
scale or grease, are to be treated in the following manner :-
§1. The first part of Invention relates to a process for providing with a
deposit or coating of copper (or what may be called coppering) lead, zinc,
antimony, platinum, or other metals or the alloys of lead, zinc, or other
metals, by dipping or immersing the same for a sufficient length of time in
astrong alkaline aquous solution of a salt of copper,containing also tartaricacid,
viz.,aquous alkaline solutions of double tartrates of copper and an alkali,such
for instance as obtained by dissolving sulphate of copper in a solution of the
double tartrate of potash and soda (salt of seignette) made strongly alkaline
by the addition of, for instance, caustic soda. The tartaric acid might be
replaced by racenic acid or other suitable organic matter, such for instance as
glycerine having the effect of preventing the oxyde of copper from precipitat-
ing by the addition of a fixed alkali. The solution may be made alkaline by
means of soda or potash, and be more or less diluted with water according as
required, and the same may be prepared, for instance, by dissolving the salt of
copper in a suitable quantity of water, to which is then added the tartaric salt
(or the glycerine) dissolved in an alkaline ley, say, for instance, soda ley.
The solution or bath thus obtained may be further diluted with water and
brought to the required strength according to the effects to be obtained.
§ 2. The next part of my Invention relates to the bronzing and colouring in
various shades of the surfaces of zinc,lead,platinum,antimony, or other metals
previously coppered by the process described in §1. For this purpose solutions
similar to those indicated in the said §1 for coppering are made use of, but
they must contain a larger quantity of the salt of copper, whereas that of the
caustic alkali and of the alkaline tartrate is to be diminished; by immersing

page_text: the coppered articles in such solutions, a slight coppering, and soon after the
bronzing or colouring of the surface to the required shade, takes place. The
solutions may be employed in the cold or in the heated state and be more or
less concentrated according to the effects to be obtained. Instead of the
tartrates, salts formed by other organic acids may be made use of. The
bronzing or colouring thus obtained I attribute to a partial oxydation of the
surface of the thin copper coating deposited on the already previously coppered
articles; and I consequently call this part of the process a partial oxydation of
the surface of the metallic coating. Zinked iron, or what is commonly
denominated galvanized iron or leaded iron, may also be coppered by immersion
in the above-mentioned solutions,but tin plate(tinned iron) formsan exception,
the tin of this latter becoming dissolved in the solution, whilst the copper
is precipitated in the state of protoxide of copper.
3. The next part of my Invention relates to the coppering, bronzing, or
colouring in various shades or colours, of wrought or cast iron, steel, and
other metals. For obtaining the said effects by the above-mentioned solutions
the metals to be coated, bronzed, or coloured, are whilst immersed in the
solution to be kept in contact with metallic zinc; probably a galvanic action
hereby takes place, and it is likely that the zinc metal may be replaced by
other metals or bodies, such as lead, for instance, acting in a similar manner.
The solutions may be employed in the cold or in the warm state, the length
of time of immersion, the strength of the solutions, and their more or less
alcalinity, be varied according as found requisite. Replacing the caustic
alkali of the solution by a bi-carbonate, the bi-carbonate of soda for instance,
a solution decomposable by iron is obtained, the copper is precipitated on the
iron,and soon after the colouring or oxydation takes place, whilst if the metal
to be coated is kept in contact with metallic zinc the same result is obtained
more rapidly.
§ 4. The next part of my Invention relates to the bronzing and colouring
of the various bronze alloys, brass, and other alloys. This I effect by
immersing bronze or other alloys in the alkaline cupreous tartrate solution
described in 1.
§ 5. The next part of my Invention relates to the silvering of copper,
wrought or cast iron, steel, or other metals, and also of zinc, lead, antimony,
wrought or cast iron, and other metals previously coppered by my processes.
For these purposes may be employed an alkaline solution formed by an aquous
solution of nitrate of silver, tartaric acid, and an excess of ammonia, to which
solution is to be added a small quantity of cyanide of potassium, but any salt
of silver may serve for the purpose, and instead of the tartaric acid any other

page_text: matter exercising a similar effect may be substituted in lieu of it. This bath
or solution is particularly applicable for silvering lead previously coppered by
my processes; zinc, coppered zinc, wrought or cast iron,and steel coppered by
my processes may also be silvered by immersion in an aquous alkaline solution
of the nitrate or the chloride of silver in an excess of cyanide of potassium or
other alkaline cyanide. The solutions or baths may be more or less diluted
with water, any salt of silver may be made use of, the ammonia be replac ed
by other suitable alkalies, and the tartaric acid be replaced by other matters
exercising an effect equivalent to that of this acid, whilst only a compara-
tively small quantity of an alkaline cyanide is required viz., so much only
as will prevent the precipitating of the silver.
I wish to add here that in the various processes above described the coating
or coatings may be obtained, lly, by mere immersion in one of the baths or
solutions, the general composition of which has been above described; whilst,
2ly, the effect of this immersion or dipping may be increased either by keeping
the metal to be coated whilst immersed in the solution incontact with metallic
zinc or any other metal or body exercising an effect equivalent to that of
the zinc metal; or, 3ly, by the aid of a galvanic battery.
My Invention is also applicable for obtaining galvano-plastic effects, and
various successive layers or coatings of different metals may be deposited,
whilst, if wished, a partial oxydation or colouring or bronzing in various
shades may be obtained by it.
The principles on which are based the various processes above described for
coating a metal by simple immersion or dipping, with one or more other
metals, are, that the metal to be coated be in presence, lly, of a solution
capable of dissolving the oxyde of the metal on which the deposit is totake place;
2ly, of a solution of the metal which is to form the deposit or coating; 3ly, of a
liquid which may be called the vehicle of the metallic oxyde, or of the metal
to be dissolved, and which liquid is to act at the same time as a reducing,
deoxydizing, or anti-precipitating agent; 4ly, of a solution prepared for the
purpose that the metal which is to form the deposit should be precipitated
on the metal to be coated in a perfectly adhering and not in the powdered
state. An adhering deposit of zinc may be precipitated on copper, on metals
already coated with copper, or on other metals. The zinking or coating with
zinc is obtained by keeping the copper or other articles in metallic contact witha
piece ofzinc whilst immersed in a very concentrated aquous solution of caustic
soda or potash,heated at from 70 to 100 degrees centigrade. In the cold state
these alkaline solutions would not give such a satisfactory result unless they
were made use of in an excessively concentrated condition, or there be added

page_text: to them an alkaline cyanuret intensely alkalinized by the addition of a fixed
caustic alkali, such for instance as caustic soda or potash, but I wish to state
here that the addition of the cyanuret is not at all indispensable. In this
process the zinc, becoming most probably oxydized by the effect of the oxygen
of the water, will dissolve itself in the alkali and partly precipitate on the
copper or other article to be coated, thus producing on this latter an adhering
and brilliant deposit of zinc. This curious precipitating of the zinc, which,
under the just-mentioned conditions, was to the best of my knowledge never
before observed, may serve for explaining several phenomenæ occuring in my
methods of coppering iron and other metals when in direct contact with zinc,
such for instance as the production of the various shades or colours of the
precipitated copper, resulting most probably from the interposition of zinc
precipitated simultaneously in more or less large quantities according to the
degree of alkalinity of the solution, the length of time of immersion, and the
degree of temperature of the bath. I have observed, besides, that zinc
thus deposited is less easily dissolved by bydro-acids, such for instance as the
hydrochloric or muriatic acid, as ordinary zinc; also that the deposit of zincon
copper takes place still more rapidly, and even with a cold solution if the zinc
that is to touch the copper be put in contact with lead in the metallic state.
It is likely that the results of my method of coppering will in the same
manner offer certain differences with those of the methods hitherto resorted to
for this purpose. For depositing a coating of iron on copper, bronze, or other
metals or alloys, a solution similar to that described above for coppering may
be employed, the salt of copper being replaced therein by one of iron, such for
instance as the perchloride of iron. The articles to be coated whilst immersed
in the solution are laid or kept in immediate contact in any other suitable
manner with a sheet or piece of zinc, and soon after an adhering and brilliant
coating of iron will be precipitated on them, particularly if the temperature
of the bath be kept at from 75 to 100 degrees centigrade. In the cold state
of the solution the deposit of iron takes place rather slow, particularly if the
solution is not excessively alkalinized, which forms a striking difference with
the process of coppering, in which satisfactorily results are likewise obtained
by means of cold solutions. It is to be understood that on the deposits or
coatings thus obtained, one or more deposits or coatings of any other suitable
metal or alloy may be again precipitated; thus, for instance, cast iron already
coated with lead by means of a very diluted solution of plumbate of lead, and
kept in contact with metallic zinc, or coated with lead by any other process,
may receive afterwards a coating of copper in a suitable solution of a salt of
copper without the aid of metallic zinc. Cast iron coppered by my methods

page_text: may afterwards receive by the ordinary known galvano-plastic process as
thick a coating of copper as may be judged proper.
The solution for coppering referred to in § 1 and 2 may, as will be
readily understood, be varied more or less, but the relative quantities of the
ingredients which have given me the most satisfactorily results are, 35grammes
of sulphate of copper, 173 grammes of tartrate of potash and soda, and 480
cubic centimetres of a solution of caustic soda of a specific gravity of about
1-14. For preparing the solution the sulphate of copper is to be dissolved in
water, whilst in another vessel not to be acted upon by caustic alkalies, the
tartrate is dissolved in the caustic soda ley,after which the solutions are mixed
together, and so much water is added as to form in all one liter. As has been
stated already the excess of caustic soda is required not only for obtaining
a perfect deposit, but also in order that the solutions may keep without
alteration. Besides, in my process of coppering in contact with zinc the excess
of zinc gives rise to the particular results spoken of in my process of zinking;
I add again, also, that by increasing considerably the quantity of the salt of
copper and diminishing that of the soda and the tartrate, I obtain the bronzing
of metals already coppered by my process, and the various shades above
spoken of, according to the composition of the baths, their degree of tem-
perature, and the length of time of immersion.
It is further to be understood that for performing the above-described
operations, vessels are to be made use of which are not to be acted upon by
the solutions made use of, or which do not act themselves on these latter;
consequently vessels of porcelain,stone, hardware, pottery, enamelled or glazed
cast iron, glass, or other similar materials, are the most suitable; in some
cases metal vessels coated on the inside with silver, platinum, or other suitable
metal may be employed. The proportions or relative quantities of the
ingredients of which my various solutions are composed cannot exactly be
stated, in as far as they must necessarily vary according to the nature of the
metals to be treated, the deposits to be obtained, and various other circum-
stances; but the said solutions must by preference be composed in such manner
that the same may be kept for a suitable length of time without alteration
for which purpose the use of an excess of the fixed caustic alkali is particularly
serviceable, and I consequently consider the application of the said excess an
an important feature of my Invention; thus, for instance, in the above-described
solution for coppering, the same would not keep unaltered for a certain length
of time if the quantity of caustic soda was to be diminished considerably
comparatively to that of the salt of copper.
Having thus described and particularly ascertained the nature of my

page_text: Invention, and the manner in which the same is or may be put into effect,
I wish it to be understood that I do not intend to restrict or restrain myself
to the exact methods or compositions described, as many variations may be
made therefrom without departing from the main features or principles of the
Invention; but what I consider to be novel and original, and consequently
claim as the Invention secured to me by the herein-before in part recited
Letters Patent is, the procesess herein described for metal coating bronzing,
and colouring metallic articles by immersing them in an alkaline solution
containing, simultaneously with a large excess of a fixed caustic alkali, a salt
of the metal, which is to form the coat,and containing tartaric acid, glycerine,
or any other suitable matter preventing the precipitation of the oxyde of the
said metal when such solution is used with or without the aid or introduction
of metallic zinc, lead, or other suitable metal or matter.
In witness whereof, I, the said Frederic Weil, have hereunto set my
hand and seal, this Twenty-fifth day of August, in the year of our Lord
One thousand eight hundred and sixty-four.
Witness,
DREYFOUS,
Eng. Civil.
FREDERIC WEIL. (L.S.)