Improvements in Processes of Coating Metals with Aluminium or its Diluent Alloys.
Year: 1893

page_text: Date of Application, 8th Aug., 1893
Complete Specification Left, 25th Sept., 1893-Accepted, 23rd June, 1894
PROVISIONAL SPECIFICATION.
Improvements in Processes of Coating Metals with Aluminium or
its Diluent Alloys.
I, EDWARD CUYLER BROADWELL, of 1434 Randolph Street, Philadelphia,
Pennsylvania, United States of America, Chemist, do hereby declare the nature of
this invention to be as follows ==
The foundation metal, after it has been cleansed which can be done in any usual
or convenient manner, as for instance by pickling, has placed upon it a chemical
compound the decomposition of which by the re-agency of molten aluminum
enables the formation of the coating.
This compound, in practice, is a haloid salt from which the basic element is
displaced by aluminum. In practice I generally use tin chloride or some halogen
compound of the more electro negative metals or of the metalloids.
To place this compound on the foundation metal, I dip the latter in a flux
containing the compound above mentioned. This compound however may be
applied otherwise than by fluxing the foundation metal, for instance by treating it
chemically such for instance as if the foundation metal be iron, treating it with
hydrochloric acid thus forming a film of chloride of iron thereon. I can also
electrically deposit or precipitate it, but I regard fluxing, which I can do most
readily and simply and which on the whole produces the best results, as the most
practical method.
After treating the foundation metal as above described, I dip it into the coating
bath. This bath is composed of the aluminum or diluent alloy which is to form
the coating. The action in the bath probably is a chemical action between the
elements of the newly decomposed compound and the aluminum and the foundation
metal but the heat generated by the chemical action induced by the decomposition
of the two metals compound may be such that a sudden heating of the surface of
the metal to be coated may occur and a very shallow alloying of the two metals
together secure. In either case however, a chemical compound being decomposed
by the re-agency of molten aluminum is the cause of the coating.
Dated this 8th day of August 1893.
E. C. BROADWELL,
By L. W., per F. B.
COMPLETE SPECIFICATION.
Improvements in Processes of Coating Metals with Aluminium or
its Diluent Alloys.
I, EDWARD CUYLER BROADWELL, of 1434 Randolph Street, Philadelphia,
Pennsylvania, United States of America, 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 foundation metal, after it has been cleansed, which can be done in any
usual or convenient manner, as for instance by pickling, has placed upon it a
chemical compound the decomposition of which by the re-agency of molten
aluminium enables the formation of the coating.

page_text: This compound, in practice, is an haloid salt from which the basic element will
be displaced by molten aluminium. In practice I generally use tin chloride or
some halogen compound of the more electro-negative metals or of the.metalloids.
To place this compound on the foundation metal, I dip the latter in a flux
containing the compound above mentioned. In practice I make the flux by:
dissolving chloride of tin (commercial) to saturation in water, the water being
heated. The solution thus formed, may be then used just as it is, for fluxing the
foundation metal, but I have found it desirable and indeed necessary, to produce
the best results, to add from time to time a small quantity of hydrochloric or other
acid sufficient to maintain the acidity of the bath, which though quite sufficiently
acid at first, becomes, after being used for a time as directed, more or less deficient
in acid. The chemical compound referred to, may, however, be applied otherwise
than by fluxing the foundation metal, for instance by treating it chemically such
for instance as if the foundation metal be iron, treating it with hydrochloric acid
thus forming a film of chloride of iron thereon. I can also electrically deposit or
precipitate it, but I regard fluxing, which I can do most readily and simply and
which on the whole produces the best results as the most practical method.
After treating the foundation metal as above described, I dip it into the coating
bath. This bath is composed of the aluminium or diluent alloy which is to form
the coating. The action in the bath probably is a chemical action between the
elements of the newly decomposed compound and the aluminium and the foundation
metal, but the heat generated by the chemical action induced by the decomposition
of the compound may be such that a sudden heating of the surface of the metal to
be coated may occur and a very shallow alloying of the two metals together occur.
In either case, a chemical compound being decomposed by the reagency of molten
aluminium is the cause of the coating.
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. Coating metals with aluminium or its diluent alloys, by placing on the
foundation metal a chemical compound decomposable by the re-agency of molten
aluminium and then dipping the foundation metal in a bath of molten aluminium
or its diluent alloy.
2. Coating metals with aluminium or its diluent alloys by placing on the
foundation metal a compound of a halogen with a metal reducible from such
combination by the re-agency of molten aluminium and subsequently dipping the
foundation metal iu a bath of molten aluminium or diluent alloy thereof.
Dated this 25th day of September 1893.
E. C. BROADWELL,
By L. W., per W. P.