IMPROVEMENTS IN COATING IRON AND STEEL WITH GOLD, SILVER, PLATINUM; OR COPPER
Year: 1865

page_text: LETTERS PATENT to Jacob. Baynes Thompson, of Rothwell Street,
Regent's Park Road, in the County of Middlesex, for the Invention of
IMPROVEMENTS IN COATING IRON AND STEEL WITH GOLD, SILVER, PLATINUM;
OR COPPER."
Sealed the 27th March 1866, and dated the 7th October 1865.
PROVISIONAL SPECIFICATION left by the said Jacob Baynes Thompson
at. the Office of the Commissioners of Patents, with his Petition,' on the
7th October 1865.
'I, JACOB BAYNES THOMPSON, of Rothwell Street, Regent's Park Road, in
the County of Middlesex, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN COATING IRON AND STEEL WITH GOLD, SILVER, PLATINUM,
OR COPPER," to be as follows:-
This Invention has for its object improvements in coating iron and steel
with gold, silver, platinum," or copper, and consists in first depositing iron
from a solution on to the surfaces of articles composed of iron or steel, and thus
obtaining thereon a coating of pure iron, and then further coating the surfaces
of the articles with gold, or silver, platinum, or copper, by deposition from a
solution of one or other of these metals. By these means it will be found that
the coating of gold, silver, platinum, or copper will be more secure and com-
plete in its holding to the iron or steel surfaces than has heretofore been the
case, when these metals have been deposited directly on to steel or iron
surfaces. The coating of pure iron is deposited on to the surfaces of the

page_text: articles, by preference, from a solution of ferrocyanide of potassium; the
articles are to be transferred. from this bath into a bath, by preference, of
the ordinary cyanide of gold, or of silver and the cyanide or sulphate of
copper.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Jacob Baynes Thompson in the Great Seal Patent Office.
on the 7th April 1866.
TO ALL. TO WHOM THESE PRESENTS SHALL COME,.. I, JACOB
BAYNES THOMPSON, of Rothwell Street, Regent's Park Road, in the County of
Middlesex, send greeting.
i. WHEREAS, Her most, Excellent Majesty Queen Victoria, by. Her Letters
Patent, bearing date. the Seventh day of October, in the year of our Lord One-
thousand, eight hundred and sixty-five, in. the twenty-ninth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Jacob Baynes Thompson, Her special licence that I, the said Jacob Baynes
Thompson, my executors, administrators, and assigns; or such others as I, the
said Jacob Baynes Thompson, 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 IRON AND STEEL WITH GOLD, SILVER, PLATINUM, OR
COPPER," upon the condition (amongst others) that I, the said Jacob
Baynes Thompson, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should par-
ticularly describe and ascertain the nature of the said Invention, and, iň
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.
86
ار
NOW KNOW YE, that I, the said Jacob Baynes Thompson, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and by
the following statement thereof, that is to say:―
'
•
This Invention has for its object improvements in coating iron and steel
with gold, silver, platinum, or copper, and consists in first depositing iron from
à solution
on to the surfaces of articles composed of iron or steel, and thus

page_text: obtaining thereon a coating of pure iron, and then further coating the surfaces
of the articles with gold or silver, platinum, or copper by deposition from a
-solution of one or other of these metals: By these means it will be found
that the coating of gold, silver, platinum, or copper will be more secure and
complete in 'its holding to the iron or steel surfaces than has heretofore-béen'
the case when these metals have been deposited directly on to" steel or-iron
surfaces.
And in order that my said Invention may be most fully understood and
readily carried into effect, I will describe the manner in which I prefer to
conduct the process.
I take ten parts by weight of ferrocyanide of potassium, and I dissolve
it in forty parts of water; so as to obtain a saturated solution in the cold!
I also prepare a solution of fused hydrate of potash by dissolving three
parts of potash in six parts of water. These two solutions I then mix together!
and I charge the depositing. vessel or tank with the mixture! In place of the
potash' solution soda may be substituted; in which case two and a half parts of
fused hydrate of soda should be dissolved in five parts of water.
The article of iron or steel. to be coated' is: thoroughly, cleaned, and is then
dipped and moved about for a short time in a mixture of hydrochloric acid
and water, say one part of acid to.one.or. two parts of water,.according to the
strength of the commercial,acid, the article is then washed in a weak alkaline
solution, and afterwards in clean water. The article is then immersed in the
depositing vessel or tank and connected with the negative pole of the battery;
and an iron plate with about the same amount of surface as the article is also
immersed in the vessel or tank and connected with the positive pole of the
battery. The bath should be kept at a temperature of from 100 to 120.
degrees Fahrenheit, and the intensity of the battery should be such that when
at work a few bubbles of gas only are given off; after a time, varying usually
from two to four hours, the article will have acquired a brilliant white silvery
appearance, it is then removed from the iron bath, washed rapidly with a cold
and nearly saturated solution of ferrocyanide of potassium, and it is at once.
transferred to the second bath for the deposition upon it of gold, silver, platinum,
or copper. For silver and gold the ordinary cyanide baths may be employed,
and the process of deposition is conducted precisely in the usual manner, and
for platinum an alkaline sodio-chloride solution or a cyanide solution is used,.
the former preferred.
For the deposition of copper on the iron-coated article I use the ordinary.
cyanide solution, or a solution of hydrated oxide of copper in hyposulphite of
soda, the following proportions are suitable:-One part of hyposulphite of
"

page_text: soda and four parts of water, to which is added as much hydrated oxide of
copper as it will dissolve... This solution should be gradually strengthened,
after the first film is deposited, and it should be worked at a temperature
of not less than 60° Fahrenheit, and with an anode of copper of about
the size of the article to be coated. If it is required to hasten the deposit,
the article can be transferred to a sulphate of copper bath after it has received
a thin deposit in either of the former baths.
The composition of the baths employed in working. my Invention: may be
varied, but those which I have described will, I believe, be found most
suitable.
Articles which will be subjected to much friction (such as knife and fork
blades, carriage harness, &c.), after being coated with silver or gold, I subject
to a heat sufficient to cause the article to char paper or wood when pressed
upon either. In case of steel articles, such as knife blades, they may be
quenched after being heated, or they may be left, previously of a little higher
temper to admit of being slightly lowered, this as it were burns the, silver or
gold into the steel or iron.
In witness whereof, I, the said Jacob Baynes Thompson, have. hereunto
set my hand and seal, this Sixth day of March, in the year of our
Lord One thousand eight hundred and sixty-six.