IMPROVEMENTS IN AND RELATING TO THE COVERING OR COATING OF METAL SURFACES CHIEFLY DESIGNED FOR THE MANUFACTURE OF WIRE
Year: 1878

page_text: LETTERS PATENT to Levi Lincoln Atwood, of Goswell Road, in the County of
Middlesex, Merchant, for the Invention of "IMPROVEMENTS IN AND RELATING
TO THE COVERING OR COATING OF METAL SURFACES CHIEFLY DESIGNED FOR
THE MANUFACTURE OF WIRE." A communication from abroad by Aaron
Blanchard Brown and Wendell Phillips Brown, both of Worcester, Massa-
chusetts, United States of America, Gentlemen.
Sealed the 15th July 1879, in pursuance of an Order of the Lord Chancellor, and
dated the 5th December 1878.
PROVISIONAL SPECIFICATION left by the said Levi Lincoln Atwood at
the Office of the Commissioners of Patents on the 5th December 1878.
LEVI LINCOLN ATWOOD, of Goswell Road, in the County of Middlesex, Merchant.
"IMPROVEMENTS IN AND RELATING TO THE COVERING OR COATING OF METAL
SURFACES CHIEFLY DESIGNED FOR THE MANUFACTURE OF WIRE." [A communi-
cation from abroad by Aaron Blanchard Brown and Wendell Phillips Brown, both
of Worcester, Massachusetts, United States of America, Gentlemen.]
This Invention is chiefly designed to be used in the manufacture of coated or
covered wire with the chemical compounds hereinafter specified, their application
to the wire being effected as hereinafter described.
The said chemical compounds are known as phosphates and phosphites, which
are products of phosphoric or phosphorous acid combined with an alkaline base.
The said Invention, is confined to this branch of chemistry and partly consists in
the combination of phosphate of soda with phosphate of ammonia, and the union of
these two phosphates in such proportions as will produce a compound somewhat
resembling what is known as "microcosmic salt or phosphate of soda with
aminonia."
This salt is to be dissolved in water in the proportions hereinafter
named, and to be applied to the wire either in a hot or cold condition in the manner
described.
Experiments have demonstrated the fact that either phosphate of soda or micro-

page_text: cosmic salt will operate as a coating and serve as such in the manufacture of wire,
but I prefer the workings of the salt on the larger wire. These compounds may be
used as dry-coating or used in solution as a wet-coating.
The methods of application of these coatings to the wire are as follows, that is
to say-The compounds are to be dissolved in water and the wire is to be
immersed in this liquid or solution, and then the liquid is to be allowed to crystalize
upon the wire becoming dry and hard; this is the dry-coating process. The wire
may also be immersed in the liquid and drawn therefrom direct through the dies;
this is wet coating. When drawn from the liquid direct the wire should previously
be coated with sulphate of copper.
The effect of this coating upon the wire is to diminish the friction when the same
is passing through the dies, thereby preventing decarbonization of the metal to
some extent. It also adds to the tensile strength of the wire and its flexibility
and will prevent its rusting during the progress of manufacture, and the said
Invention tends to preserve it from corrosion after it is finished.
Wire drawn in this coating can be galvanized without re-annealing or even
scouring, and as the friction is less than when the wire is drawn with other coating
it can be reduced more at one drawing than ordinary wire, and the chemical effect
upon the metal tending to soften the same obviates the necessity for frequent
annealings, thereby lessening the liability to decarbonization during the process of
manufacture.
I use about three pounds of the salt or of the sulphate of soda to one gallon of
water.
I may use all combinations of phosphoric or phosphorus acid with any alkaline
base for metals of all kinds to prevent corrosion.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Levi Lincoln Atwood in the Great Seal Patent Office on the 15th
July 1879.
LEVI LINCOLN ATWOOD, of Goswell Road, in the County of Middlesex, Merchant
"IMPROVEMENTS IN AND RELATING TO THE COVERING OR COATING OF METAL
SURFACES CHIEFLY DESIGNED FOR THE MANUFACTURE OF WIRE." A communi-
cation from abroad by Aaron Blanchard Brown and Wendell Phillips Brown, both
of Worcester, Massachusetts, United States of America, Gentlemen.
This Invention relates chiefly to the manufacture of coated or covered wire. It
comprises an improved method of treating wire in its manufacture and subsequent
coating with a more costly metal, and it has for one of its objects to produce on the
wire, previously to drawing the same, a coating which will serve as a lubricant
when it is passed through the dies, and will modify it in such manner as to add
greatly to the capacity of the finished wire to bear tensile strains, increase its
flexibility, prevent its wasting during the drawing process, and preserve it from
corrosion when finished and especially while in store.
In practising the said Invention the wire is coated previously to the drawing
operation with alkaline phosphates, such as the phosphate of soda or double
phosphate of soda and ammonia, the latter being commonly known as microcosmic
salt.
The phosphate is dissolved in water or other menstruum, and the wire is
immersed or drawn through the solution. The wire may then be subjected directly
to the drawing process, or the coating may be allowed to crystallize and dry upon
the wire which is then subjected to the drawing process.
When the wire is subjected directly to the drawing process after coming from
the solution it is preferable to coat it with copper, previously to applying the above-
named solution, by immersion in a bath of sulphate of copper, as sometimes practised
in the ordinary method of drawing wire.
In practice it is found that the alkaline phosphates known as phosphates of soda,
or the double phosphate of soda and ammonia, or microcosmic salt will answer well,
although other alkaline phosphates may be used.
The salt is to be dissolved in water in the proportions of from one to four pounds
of crystals to one gallon of water, according to the size of the wire to be treated
and the quality of metal of which it is composed. The smaller the wire the
weaker the solution should be, and the above named proportions may be varied
considerably.
By this improved method of treating the wire the friction upon the same when
passing through the die is materially diminished. I thereby increase the capacity
of the finished wire to bear tensile strains and make it more flexible, rendering
frequent reannealing unnecessary, and obviate the necessity for subsequent scouring
previous to galvanizing; this treatment moreover prevents corrosion of the wire
especially while in store. In addition to these advantages the wire can be more
readily reduced, owing to the softness which the coating imparts to the metal.
In galvanizing wire, and tinning wire, and covering wire formed from all baser
metals with metals of a more costly kind, I employ in place of the acids now used
to cleanse the body to be covered, a chemical compound of an alkaline phosphatic
character to be followed by treatment or coating with caustic alkali, which acts
upon the phosphatic coating as a cleanser and operates in conjunction with the said
phosphatic coating as a flux in the subsequent treatment of the metal and causes
the superimposed metallic coating to have a smooth and bright appearance.
In the ordinary methods of covering one metal with another of a more costly
and valuable kind it has been found necessary to use some kind of acid to remove
the foreign matter or substances which may have accumulated upon the surface of
the metal to be coated, the acid and salts formed being subsequently removed before
coating the said surface.

page_text: But by subjecting the metal to the action of alkaline phosphates, followed by
treatment with caustic alkali, the wire will be prepared for the reception of the
metal with which it is to be coated or plated, and a compound will be formed
thereon which will act as a flux in the subsequent operations. Therefore the sub-
sequent treatment for the removal of the compound is unnecessary, and a much
better union of the two metals and a smoother and brighter appearance of
the metallic coating will be obtained. In applying these chemical compounds
in the processes above named I dissolve the solid compounds in water, and then
first apply the alkaline phosphatic solution to the surface of the said wire, and
after the wire has been drawn between pads in the usual manner and cleansed
and wiped or drawn through a die, I apply a coating of a solution of caustic
alkali as a flux in the same manner that acids have hitherto been used in
galvanizing and tinning wire. This treatment is followed by the application of
the metal coating by the usual method.
The effect of these alkaline phosphates and caustic alkalies upon the metal after
it is covered is of a non-corroding tendency, and thereby obviates the now universal
tendency of all plated and galvanized bodies to corrode beneath the plate by the
action of the acid heretofore used in cleansing the body covered especially when
such body is iron or steel.
The solution of caustic alkali may be of any suitable strength, say, from one to
three pounds of caustic alkali to one gallon of water according to the strength of
the caustic alkali.
Having thus fully described the said Invention, and the manner of performing
the same,
I wish it understood that I claim,-
First. The improved method of preparing wire consisting in coating the wire
previously to drawing the same with alkaline phosphates, substantially as
specified.
Second. The method of preparing wire made of one metal for coating with
another metal by subjecting the same to the action of alkaline phosphates followed
by treatment with caustic alkali, whereby a compound is formed on the metal
which operates as a flux, and the surface of the same is prepared for the reception
of the metal coating, substantially as specified.
In witness whereof, I, the said Levi Lincoln Atwood, have hereunto set my
hand and seal, this Fifteenth day of July, in the year of our Lord One
thousand eight hundred and seventy nine.
L. L. ATWOOD. (L.S.)