IMPROVEMENTS IN THE PREPARATION AND IN THE ELECTRO-DEPOSITION OF NICKEL UPON METALS
Year: 1874

page_text: PROVISIONAL SPECIFICATION left by William Baker and John Unwin
at the Office of the Commissioners of Patents, with their Petition,
on the 29th April 1874.
WC, WILLIAM BAKER and JOHN UNWIN, both of Sheffield, in the
County of York, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE PREPARATION AND IN THE ELECTRO-DEPOSITION OF NICKEL
UPON METALS," to be as follows:-
:―
Our Invention relates to and consists in the preparation and use of an
improved solution of nickel for the purposes of the electro-deposition
of that metal upon iron, copper, and other metallic and conducting
surfaces.
We are aware that nickel has been deposited from various solutions
and especially from solutions of the double sulphate and double chloride
of nickel and ammonium.
.
Our improved solution is composed of nickel oxide and an alkali such

page_text: as soda, potash, or ammonia, or a mixture of two or all of these alkalies,
and the whole dissolved in tartaric acid; thus we make a solution with
either nickel, oxide, soda, and tartaric acid, nickel oxide, potash, and
tartaric acid, nickel oxide ammonia, and tartaric acid, or a mixture of
two or all these solutions, and we use the resulting solution as a bath for
the electro-deposition of metallic nickel, which will produce a reguline
adhesive deposit.
:
The mode of preparing the solutions may be varied, but the following
method we have adopted :-We make a solution of any of the ordinary
salts of nickel, which may be prepared from commercial nickel by
processes which are well understood, such as the nitrate, the chloride, or
the sulphate of nickel. The sulphate of nickel purified by repeated
cystallizations we find extremely suitable for this purpose. To the
solution of the nickel salt we then add caustic potash or caustic soda
previously dissolved in water until the whole of the nickel hydrate is
precipitated. The precipitate is allowed to settle, the clear liquor is
drawn off, and fresh water added so as to wash the precipitate in the
well known manner, the process being repeated as often as necessary.
Instead of the caustic alkalies as above described the carbonates of
the alkalies may be used to precipitate the nickel salt, the precipitate
obtained being washed in like manner.
.
To the precipitate obtained by one or any of the above methods we
add tartaric acid, dissolved in a suitable quantity of water, and then
caustic soda, ammonia, or potash until a neutral or nearly neutral
solution is obtained.
The proportions we find most suitable are such as form a double
tartrate of nickel and the alkalies employed.
Instead of adding tartaric acid and the alkali uncombined, we some-
times employ acid tartrates of the alkalies such as cream of tartar, which
is the acid tartrate of potash, in suitable proportions to the nickel hydrate
so as to form the double tartrate of the metal and the alkali.
The following are the proportions which we find convenient, namely,
100 lbs. sulphate of nickel, 53 lbs. tartaric acid, 14 lbs. caustic soda, but
we do not confine ourselves to these proportions as more or less of the
neutral alkaline tratrate may still be employed with successful results;

page_text: or we take 100 lbs. sulphate of nickel, 67 lbs. cream of tartar. The
quantity of water used for either of these mixtures may be varied
according to the strength of solution required, but we find good results
are obtained with 100 gallons of water to the 100 lbs. of sulphate of
nickel employed.
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