A New or Improved Process for the Electro Deposition of Aluminium and Aluminium Alloys.
Year: 1894

page_text: Date of Application, 11th Apr., 1894
Complete Specification Left, 11th Feb., 1895-Accepted, 11th June, 1895
PROVISIONAL SPECIFICATION.
A New or Improved Process for the Electro Deposition of Aluminium
and Aluminium Alloys.
I ALFRED FRANCIS BILDERBECK GOMESS of 24 Alfred Place West South
Kensington in the County of London Chemist do hereby declare the nature of this
invention to be as follows:-
C
The object of this invention is to electro-deposit aluminium on metallic and other
suitable surfaces either in a pure state or otherwise.
According to this invention after having prepared the article to be plated in the
ordinary way or by any suitable means as practised for the deposition of silver and
other metals I electro deposit the aluminium or aluminium alloy by the employment
of a bath consisting of a solution of tartrate of aluminium in conjunction with
chloride of an alkali either with or without the addition of iodide or bromide of an
alkali. This bath may be used either hot or cold.
Dated this 11th day of April 1894.
A. F. BILDERBECK GOMESS.
A New or Improved Process for the Electro Deposition of Aluminium
and Aluminium Alloys.
I ALFRED FRANCIS BILDERBECK GOMESS, of 24 Alfred Place West, South
Kensington, in the County of London, Chemist, 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 object of this invention is to electro-deposit aluminium and aluminium
alloys, and it consists of a process or method by which the metal is deposited from
an aqueous solution of special composition upon other metals or non-metallic
surfaces, which if necessary are prepared and coated with conducting material.
I have found that my process can, if desired, be carried on successfully in a cold
bath.
The electrolyte used is tartrate of aluminium Al,(CHO), in conjunction with
the chloride of an alkali, to which may be added the iodide or bromide of an
alkali.
The following are the compositions of certain baths which I have found to

page_text: The conductivity may be increased by raising the temperature of the bath. The
temperature which I have found to answer is from 80 to 115 degrees Fahrenheit.
To either of the above baths iodide or bromide of an alkali (or both) may be
added.
For the single tartrate of aluminium it is obvious that a double tartrate of
aluminium and an alkaline base may be substituted.
The baths may of course be made up in such other proportions as may be found
suitable in the various uses to which they are to be put; but the proportions given
above produce the best results, and should not be greatly varied.
In order to continue the process, it is necessary to supply to the bath aluminium
to replace that deposited. I effect this by adding freshly precipitated hydroxide of
aluminium Al, 6 HO, so as to keep the bath well charged with aluminium, or by the
use of an aluminium anode. The baths may be rendered richer in aluminium by
boiling for a short time with freshly precipitated hydroxide of aluminium.
In plating with aluminium I take the article to be plated, and after preparing it
in a similar manner to that practised for silver plating, I connect it with the
negative pole of a dynamo or battery in the usual way, and I either use aluminium
anodes, connected with the positive pole, or I may use anodes of carbon, platinum
or other suitable material (e.g. that will not dissolve in the aforesaid baths) dipping
into the bath containing the electrolyte, to which bath hydroxide of aluminium may
be continuously added, to replace the aluminium deposited on the cathode. In this
case the electrolyte should be kept continuously agitated.
When I plate with an aluminium anode I work the bath in a neutral or slightly
alkaline state, but when other anodes above described are used, the bath can be
worked in an acid, neutral or alkaline state.
When the surface to be plated is a non-conductor of electricity, I render such
surface a conductor by any suitable means.
When it is desired to plate with aluminium alloys I add to the above-described
electrolyte, in the ordinary way, a suitable salt of the metal which I wish to alloy
with the aluminium. The tartrate or chloride should be taken. For instance in
the case of an alloy with tin, I add to my bath about ten per cent. of chloride
of tin.
.
It is evident that the proportions may be varied as they constitute no essential
part of my invention.
For the deposition of aluminium the voltage I have found suitable is from
4 to 10 volts and upwards.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The electro-deposition of aluminium in an aqueous bath by the employment
of tartrate of aluminium.
2. The electro-deposition of aluminium in conjunction with other metals in an
aqueous bath so as to form alloys, by the employment of tartrate of aluminium.
3. In the electro-deposition of aluminium and aluminium alloys in an aqueous
bath the employment of tartrate of aluminium in conjunction with chloride of an
alkali.
4. In the electro-deposition of aluminium and aluminium alloys in an aqueous
bath the employment of double tartrate of aluminium and an alkaline base.
5. In the electro-deposition of aluminium and aluminium alloys in an aqueous
bath, the employment of double tartrate of aluminium and an alkaline base in
conjunction with chloride of an alkali.
6. In the electro-deposition of aluminium and aluminium alloys in an aqueous
bath the employment of tartrate of aluminium or the double tartrate of aluminium
and an alkaline base, in conjunction with iodide or bromide of an alkali, with the
addition of chloride of an alkali.

page_text: 7. The improved process for the electro-deposition of aluminium substantially as
described.
8. The improved process for the electro-deposition of aluminium alloys sub-
stantially as described.
Dated this Eleventh day of February 1895.
BROWNE & Co.,
9, Warwick Court, Gray's Inn, London, W.C.,
Agents for the Applicant.