Year: 1886

page_text: Date of Application, 16th Aug., 1886.
Complete Left, 29th Mar., 1887.
Complete Accepted, 29th Apr., 1887.
I, WILLIAM ARTHUR THOMS, of 44 St. Oswald's Road, West Brompton, London,
in the County of Middlesex, England, Electrician, do hereby declare the nature of
this invention to be as follows:-
My invention relates to the deposition of metallic platinum upon metal or other
suitable substance by means of any suitable and well known electro-typing or plating
arrangement and a specially prepared bath.
And my invention has for its object the deposition of the platinum with greater
economy, solidity, and in greater perfection than in the methods hitherto adopted for
the purpose.
In the methods hitherto employed the deposit of platinum obtained has been dull,
and requires to be polished after being removed from the bath, whereas by my
invention I obtain a deposit which is itself so bright that it requires no subsequent
polishing. This feature constitutes in itself an important advantage effected by my
invention, as the cost of polishing is entirely abolished.
My invention consists in the employment with the above mentioned electro arrange-
ments, of a bath made in the following manner :-
I take either a solution of pure platinum metal or a solution of platinic ore in what
is known as "
aqua regia” or nitro-hydrochloric acid, the platinum being dissolved in
the usual manner, and the solution subsequently rendered neutral by any of the usual
methods; or I may employ a solution of chloride of platinum. To this solution of
platinum I add a weak solution of the ordinary phosphate of soda. I next add a
weak solution of the ordinary phosphate of ammonia, and I then boil the whole for
several hours, and during such boiling operation I add chloride of sodium solution.
The proportions that I prefer to use of the above mentioned ingredients are as
follows:-
1 oz. chloride of platinum.

page_text: The whole of the ingredients to be dissolved in sufficient water and used to make
1 gallon of solution.
The above proportions may be varied, but I find those above given will produce
good results.
The solution may be used at any suitable temperature, but I prefer to use same
above the normal temperature of the atmosphere. A strong current of electricity
must be employed, and the cathode of the electric apparatus is preferably kept in
motion during the operation of depositing the platinum.
The same bath may be employed for a considerable time by keeping it up to its
original strength by the addition of fresh platinum solution and chloride of sodium
solution.
The duration of the exposure of the articles or surfaces to be coated to the action of
the electrolytic bath, will depend on the temperature at which the operation is carried
on, the distance between the anode and cathode, the nature of the current employed,
and the thickness of coating desired; the density and degree of fineness of the deposit
also naturally depending upon these conditions.
When desired to coat surfaces to which the platinum will not adhere directly, they
must be first coated in any suitable manner with a substance to which platinum will
adhere.

page_text: COMPLETE SPECIFICATION.
Improvements in the Deposition of Platinum by Electricity.
I, WILLIAM ARTHUR THOMS, of 44 St. Oswald's Road, West Brompton, London,
in the County of Middlesex, England, Electrician, 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:-
My invention relates to the deposition of metallic platinum upon metal or other
suitable substance by means of any suitable and well known electro-typing or plating
arrangement and a specially prepared bath.
And my invention has for its object the deposition of the platinum with greater
economy, solidity, and in greater perfection than in the methods hitherto adopted for
the purpose.
In the methods hitherto employed the deposit of platinum obtained has been dull,
and requires to be polished after being removed from the bath, whereas by my
invention I obtain a deposit which is itself so bright that it requires no subsequent
polishing. This feature constitutes in itself an important advantage effected by my
invention, as the cost of polishing is entirely abolished.
My invention consists in the employment with the above mentioned electro arrange-
ments, of a bath made in the following manner:
I take either a solution of pure platinuin metal or a solution of platinic ore in what
is known as "aqua regia" or nitro-hydrochloric acid, the platinum being dissolved in
the usual manner, and the solution subsequently rendered neutral by any of the usual
methods; or I may employ a solution of chloride of platinum. To this solution of
platinum I add a weak solution of the ordinary phosphate of soda. I next add a
weak solution of the ordinary phosphate of ammonia, and I then boil the whole for
several hours, and during such boiling operation I add chloride of sodium solution.
The proportions that I prefer to use of the above mentioned ingredients are as
follows:-
1
2

page_text: The same bath may be employed for a considerable time by keeping it up to its
original strength by the addition of fresh platinum solution and chloride of sodium
solution.
The duration of the exposure of the articles or surfaces to be coated to the action of
the electrolytic bath, will depend on the temperature at which the operation is carried
on, the distance between the anode and cathode, the nature of the current employed,
and the thickness of coating desired; the density and degree of fineness of the
deposit also naturally depending upon these conditions.
When desired to coat surfaces to which the platinum will not adhere directly, they
must be first coated in any suitable manner with a substance to which platinum will
adhere.
Having now particularly described and ascertained the nature of my said Invention,
and in what manner the same is to be performed, I declare that what I claim is :-
:-
In the process of depositing platinum by electricity, the employment of a bath
consisting of a solution of platinum in the form of a chloride, to which is added a
solution of ordinary phosphate of soda, and then a solution of ordinary phosphate of
ammonia, the whole being subsequently boiled, and chloride of sodium solution added,
all substantially as specified.