Year: 1888

page_text: I LÉON QUENTIN BRIN, of 6 Rue Wilhem, Auteuil, Paris France, Engineer do
hereby declare the nature of this invention to be as follows:-
This invention relates to a process of plating iron and other metals with an adherent
coating of pure aluminum. The invention consists in effecting the deposit of a firmly
adherent coating of aluminum by the direct contact with the iron or other metal
suitably prepared, of metallic vapors resulting from the decomposition and volatilization
by heat of salts of aluminum. It also relates to the apparatus whereby the operation
can be continuously repeated on a commercial scale, the said apparatus comprising
the employ ment of muffles or bermetically closed chambers whereby the presence of
air or of oxygen is excluded during the operation.
The process of plating iron or other metal with aluminum is carried out in the
following manner :-
The sheets or articles of iron or other metal to be plated with aluminum are first
cleansed of all impurities by means of a suitable acid and afterwards immersed in a
solution either of borate of soda or other flux mixed with a certain quantity of salts
of alumina or hydrated alumina mixed with easily fusible fluxes whereby the surfaces
to be plated are maintained in a state of great purity. These fluxes also serve to prevent
the oxidation of the metal upon which the aluminum is to be condensed as hereafter
explained, as the result of the decomposition of the vapors of aluminum.
The articles thus treated are placed in a closed chamber or muffle contained within
a furnace by which the muffle is heated externally to a very high temperature. The
muffle which resembles an enamelling furnace is provided with means of admitting
the metallic vapors and of permitting the escape of the gases resulting from the
decomposition and the vapors produced in the operation. The internal temperature of
the muffle should be raised to 1000° to 1500° C. before the vapors are introduced.
A vessel of fire clay capable of being heated directly or on a sand bath and containing,
say chloride of aluminum, is heated to the temperature necessary for the volatilization

page_text: of this salt, the resulting vapors passing through the admission tube and filling the
heated muffle, wherein, on meeting the metallic surfaces, the vapors are decomposed,
aluminum being deposited upon the iron or other metal.
The outlet tube from the muffle conducts the gases and vapors into a receiver having
a large surface and provided with a tube or channel whereby the vapors are conducted
into a vessel containing water and are there condensed without inconveniencing
the operator.

page_text: I, LEON QUENTIN BRIN, of 6, Rue Wilhem, Auteuil, Paris, France, 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 a process of plating iron and other metals with an
adherent coating of pure aluminium.
The Invention consists in effecting the deposit of a coating of aluminium by
the direct contact, with the iron or other metal suitably prepared, of aluminiferous
vapors resulting from the decomposition or volatilisation, by heat, of salts of
aluminium. The apparatus whereby the operation can be continuously repeated
on a commercial scale, comprises the employment of mufles or closed chambers
whereby the presence of air or of free or active oxygen is excluded during the
operation.
The process is carried out in the following manner :-The sheets, pieces, or
articles of iron or other metal to be plated with aluminium are first cleansed of
all impurities by means of a suitable acid bath or by other well known means,
and are then immersed in a flux composed of borax and other substances made
in the following manner :-100 parts of clay or other earths or mineral substances
rich in alumina, 125 parts of chloride of sodium or other suitable chloride,
15 parts of fluor spar, 25 parts of borax are made into a paste with water and
uniformly spread over or otherwise applied to the articles to be treated. This
flux serves to maintain the surfaces of the metal clean and free from oxidation.
Another suitable flux may be made by mixing 2 parts of borax with 4 parts of
chloride of aluminium, 2 parts of chloride of sodium and 1 part of carbonate of
a thin paste. The
soda, the whole powdered and mixed with water to
metal so treated is placed in a muffle or closed chamber which may be of fire
clay or iron lined with fire clay or other suitable material. The muffle is heated
externally to a very high temperature and is provided with the means of admitting
the metallic vapors and gases used in the operation and of leading off the residual
gases into a separate chamber; for iron, the muffle should be raised, before the
aluminiferous vapors are introduced, to a temperature of 1000° or 1500° C., and
for other metals it may be raised to a temperature approaching the melting point
of the metal or it may if desired exceed that temperature.
A separate retort is provided for the purpose of generating or forming
aluminiferous vapors, and this retort is provided by preference with an inlet
through which is conducted a current of hot nitrogen or similar inert gas, or a
reducing gas, to drive or carry forward the aluminiferous fumes into the muffle
chamber and to prevent condensation; a suitable gas for this purpose may be

page_text: condition so as to deprive the air of free or uncombined oxygen. The air or gas
is driven through the retort into the muffle chamber by means of a suitable pump or
other appliance. The retort is charged either with chloride of aluminium or with
materials for producing the same by the reaction set up at a high temperature.
When chloride of aluminium is not used, a suitable mixture for this purpose will
be as under, but the proportions may be varied :—
or
Clay or other aluminous earth
Chloride of Sodium
Fluor Spar
Clay or other aluminous earth
Chloride of Sodium
Borax.
-
100 parts.
"
""
-
125
15
100 parts.
125 23
10 "
In repeating the operations, the borax may be replaced by twice its weight of
pulverised slag from the retort obtained from previous operations. The clay or
earth used for this purpose should by preference contain at least 50% of alumina ;
if richer it may be employed in smaller proportion. The muffle chamber contain-
ing the metal to be impregnated having been heated to the proper temperature,
sufficient heat is applied, by a sand bath or otherwise, to the retort containing the
chloride (or the mixture for producing the chloride) of aluminium, to produce
aluminiferous vapors. The operation in the muffle chamber commences with the
reduction af aluminium from the flux coating the articles and is continued by the
supply of aluminiferous
from the retort.
vapor
The flux may be used without
the aluminium chloride or other aluminous compound, but with less advantage, as the
deposit of aluminium will not commence until the vapors from the retort act on the
flux coating the metal placed in the muffle.
It is obvious that although it is preferred to generate the aluminiferous vapors in a
separate retort, the muffle uight be employed for the double purpose of generating
and utilizing the aluminiferous vapors, the temperature being suitably regulated at
different parts of the muffle for this purpose.
I prefer to use the chloride of aluminium, or a mixture producing the chloride,
though the process may be effected by other haloid salts of aluminium, but with less
advantage.
If the metal be in sheets or plates it is evident that one side of the plate may be
protected by sand or otherwise, in which case only the exposed side of the plate will
absorb the aluminium which will penetrate into the metal to a depth varying with the
degree of heat and time employed.
The outlet tube from the muffle chamber conducts the gases and vapors into a
receiver having a large condensing surface on which the sublimated vapors will be
deposited. The products thus obtained may be employed in subsequent processes;
the residual gases are conducted into a vessel which may contain water, and are there
condensed; hydrate of alumina being deposited while soluble chlorides and chlorine
are collected which may be utilized as bye-products.
It is also obvious that other liquids whether inert (as petroleum) or otherwise may
be employed instead of water if it be desired to collect the aluminium chloride or the
double chlorides of aluminium and sodium without decomposition into hydrates by
the action of water.
In the operation of plating by this invention I find that the metal plated becomes
not only covered with but impregnated (to a greater or less extent dependent upon
the temperature and duration of the operation) with aluminium, so that although the
plating of pure aluminium may be removed, by wear or otherwise, the metal is so
permeated by the aluminium as to be effectually protected by its presence and acquire
the properties of an alloy with aluminium.

page_text: Having now particularly described and ascertained the nature of the said 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 plating iron or other metal with aluminium,
which consists in coating the metal with a flux containing chloride of aluminium, clay,
or other aluminous earth, and then exposing the surfaces thus coated in a heated state
to aluminiferous vapors, as herein described.
2. The herein described step in the process of plating iron or other metal with
aluminium, which consists in effecting the reduction by heat of a flux containing
either chloride of aluminium or clay or other aluminous earth, in direct contact with
the surface to be plated, whereby a coating of metallic aluminium is deposited upon,
and penetrates, the metal.
3. The herein described step in the process of plating iron or other metal with
aluminium, which consists in exposing the metal previously coated with any suitable
flux and in a heated state, to aluminiferous vapors, as described.
4. In the herein described process of plating iron, or other metal, with aluminium,
the production and collection in the manner described of the bye-products specified.
Dated this 7th day of December 1888.
LÉON QUENTIN BRIN.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.
LÉON QUENTIN BRIN.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.