Improvements in or connected with the Coating of Metals or Metal Articles with other Metals or Alloys.
Year: 1891

page_text: Date of Application, 5th May, 1891-Accepted, 13th June, 1891
COMPLETE SPECIFICATION.
Improvements in or connected with the Coating of Metals or Metal
Articles with other Metals or Alloys.
A communication from abroad by FRANCIS JULIUS CLAMER, of Richmond Street,
Philadelphia, in the State of Pennsylvania, United States of America, Chemist
and Metallurgist.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for
Foreign Patent Solicitors, 6, Lord Street, Liverpool and, 6 Bank Street,
Manchester, both in the County of Lancaster and 323 High Holborn in the
County of Middlesex, Civil Engineer, 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 :-
This invention relates to coating metals, generally, such as iron et cetera and has
for its object a process for preparing and coating plates and other metal articles
whereby they are thoroughly cleaned and coated.
In the ordinary process of coating metals, the plates or other articles are first
immersed in a pickle or bath made of sulphuric acid and water, and, when taken
out, are rinsed in water. This treatment leaves upon the articles a deposit of
sulphuretted hydrogen which prevents a proper union of the coating metal with the
metal of the article. By the present invention, this sulphuretted hydrogen is
removed by immersing the plate or other article in a bath of muriatic acid.
It is also found that plates and other articles treated under Mr. Clamer's Patent
No. 363,593 of the United States dated May 24, 1887, in which they are made the
negative pole of an electric current in a cyanide bath, have a deposit of cyanide of
iron upon them when they are removed from the bath, which
prevents the proper
adhesion of the coating metal. This may also be removed by immersing the plate
or other article in a muriatic acid bath, as in the previous case.
After removing the plates or other articles from the muriatic acid bath, whether
the same succeeds one or the other of the cleansing baths above referred to, they
are then immersed in or coated lightly with a bath made of a saturated solution of
tin, zinc and muriatic acid, which is formed of equal parts of tin and zinc dissolved
in muriatic acid, in sufficient quantity to saturate the muriatic acid. To get the
best effects from the bath, the zinc and tin are first melted together and granulated
in water and thereby rendered more readily soluble in the muriatic acid. The
immersion or coating in this bath gives the plates a thin covering of the saturated
solution, which forms an adhesive surface for the succeeding metal bath into which
they are then immersed.
The coating bath which is preferably used is that produced under United States
Patent, No. 283,077 of August 14 1883, and is formed of ordinary pig-lead having
mingled with it sal-ammoniac, arsenic, phosphate of lead, or phosphorus and a
suitable flux, such as borax. To make this bath, to every hundred pounds of lead
while in the molten state is added three ounces, more or less, of sal-ammoniac:
half ounce, more or less, of arsenic; three ounces, more or less, of phosphate of
lead or phosphorus; and half an ounce, more or less, of borax or a similar flux. In
addition thereto, a small percentage of the saturated solution of tin, zinc and
muriatic acid, which may be mixed with the sal-ammoniac, may be added.
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 by
my foreign correspondent, I declare that what I claim is ;-
1. The herein described process of preparing and coating metal plates or other
metal articles, consisting in cleansing them in suitable cleansing bath, then immersing

page_text: them in a bath of muriatic acid, then immersing or coating them in a bath of
saturated solution of tin, zinc and muriatic acid, and finally coating them in a
suitable metal coating bath, as set forth.
2. The herein described process of preparing and coating metal plates and other
metal articles, consisting in cleansing them in a suitable cleansing bath, then
immersing them in a bath of muriatic acid, then immersing or coating them in a
bath of saturated solution of tin, zinc and muriatic acid, and finally coating them
in a bath composed of lead, sal-ammoniac, arsenic and phosphate of lead or
phosphorus, substantially as and for the purpose set forth.
Dated this 4th day of May 1891.
WM. P. THOMPSON & Co.,
Agents for the Applicant.