Manufacture of Coated Metallic Powders.
Year: 1894

page_text: Date of Application, 26th June, 1894-Accepted, 4th Aug., 1894
COMPLETE SPECIFICATION.
[Communicated from abroad by JOSEPH SACHS, of 14, Dey Street, New York,
United States of America, Merchant.]
Manufacture of Coated Metallic Powders.
I, OLIVER IMRAY, of No. 28, Southampton Buildings, Chancery Lane in the
County of London, Chartered Patent Agent, 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 the manufacture of metallic powder each particle of
which consists of a core of one metal and a shell of another, the powder thus
produced being applicable to purposes to which bronze powders, flitters or flakes,
and metallics or large granules are applied, but at a less cost.
The process of manufacture according to this invention is based upon the
principle that certain metals when immersed in a solution of a metallic salt receive
a coating of the metal which is the base of the salt, provided that the metal
immersed is more electro-positive than the metal which is the base of the salt.
As an example, may be described the process for the manufacture of a metallic
powder, each particle of which consists of a core of zinc covered by a shell of
brass.
For this purpose, ordinary zinc powder is first thoroughly cleansed in any suitable
chemical or mechanical manner and is then introduced into a bath prepared as
follows:
An aqueous solution of sulphate of copper and sulphate of zinc is prepared and
to it is added a sufficient quantity of potassium cyanide to dissolve the resulting
precipitate. To the solution thus formed is added from one-tenth to one-fifth of
aqua ammonia and the entire solution is diluted with water to about 8° Beaumé,
being then ready for reception of the zine powder.
Equal quantities of the metallic salts may be employed, or their proportions may
be varied, the product having different colours or properties according as the one
or the other of the metals predominates.
It is essential to maintain a continual and uniform agitation of the particles in
the bath and this may be effected by any suitable known apparatus.
The particles of zinc powder in the bath become gradually covered with a
deposit of metallic brass. When they are generally covered, the agitation is
etopped, and the coated powder is removed, thoroughly washed in water and dried.
The product may be polished in any suitable manner.
Obviously other metallic bases may be substituted for the zinc and copper the
principles underlying the invention remaining the same, and the product may be
submitted to a second immersion or to treatment by electrolysis, or by heating in
order to obtain farther coating or special colour.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The herein described process of manufacturing metallic powders each particle
of which consists of a core and shell by immersing and agitating the core particles
in a suitable solution of salts of metal more electrò negative.

page_text: 2. Metallic powder having its metallic particles coated with other metal by
immersion in a solution and treatment substantially as described.
Dated this 26th day of June 1894.
ABEL & IMRAY,
Agents for the Applicant.