AN IMPROVED PROCESS FOR COATING IRON WITH ZINC OR TIN OR COMPOUNDS THEREOF, WHICH INVENTION COMPRISES AN ALLOY AND SOLUTIONS TO BE USED IN SUCH PROCESS
Year: 1880

page_text: PROVISIONAL SPECIFICATION. left by William Robert Lako at the Office.
of the Commissioners of Patents on the 19th April 1880. A communication
from abroad by John Benbow Jones, Metallurgist, and Henry Wardwell
Shepard, Manufacturer, both of Brooklyn, and Robert Seaman, of the City of
New York, Merchant, all in the State of New York, United States of
America.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "AN IMPROVED PROCESS FOR COATING IRON
WITH ZINC OR TIN OR COMPOUNDS THEREOF, WHICH INVENTION COMPRISES AN ALLOY
AND SOLUTIONS TO BE USED IN SUCH PROCESS." [A communication from abroad"
by John Benbow Jones, Metallurgist, and Henry Wardwell Shepard, Manu-
facturer, both of Brooklyn, and Robert Seaman, of the City of New York, Merchant,
all in the State of New York, United States of America.]
This Invention includes a process comprising the use of a neutralizing bath
hereinafter described for preparing sheets or other iron articles to be coated after
the usual pickling or cleaning operation has been performed and previous to
immersion in the metallic bath for the purpose of decomposing the injurious ferric
salts from the fibres of the iron, thereby removing an injurious and destructive
element to the durability of the iron through deliquescence and exposure to moist
atmospheres.
It also comprises the use of a flux bath for the purpose of removing any
oxidation or preventing its formation as the sheets or articles are passed into the
metal bath, thereby rendering unnecessary the use of muriatic acid and drying the
samo in an oven or otherwise, as now practiced to the great injury of the texture
of the iron, and also the great detorioration of the metal from the admixture of
iron resulting from the decomposition of that portion of the dried ferric salts
remaining upon the surface.
It further comprises a special alloy of zinc, tio, lead and nickel to be applied to
the prepared articles as a metal bath.
The said improved preparatory process may be profitably used with the ordinary
bath of melted zinc, although it is especially adapted to the aforesaid new alloy of
zinc, tin, lead and nickel. And this alloy may be used in connection with other
preparatory or neutralizing processes.
I will describe the said improvements as used in coating sheet iron with the

page_text: above named new alloy of zinc, tin, lead and nickel. The operations according to
this Invention are carried into practice as follows, that is to say,-
The sheets of iron are first cleaned to remove the scale and dirt in the ordinary
bath of dilute acid, and are then washed in clear water and inspected, as in the
common process of "galvanizing." The sheets thus washed are then put into a
bath of water containing about one or two per cent, of any fusible metallic or
organic chloride whose bases are positive to iron, such as methyl or ethylamino
chlorides, ammonium, or zinc chloride. Into (say about 100 gallons) of this solution
I stir about 4 or 5 pounds of the oxide or surface dross of the metal or alloy intended
to be used as the metal bath. The addition of this oxide furnishes an element
contained in that portion of zinc of which it is composed, which materially assists
in decomposing the ferric salts in the iron forming a positive element to the
negative ferric salts as there always remains a sufficient amount of free acid in the
pores of the iron to excite action although it may have been washed in
water. In use the temperature most suitable is about 120° Fahrenheit. The sheets
of iron when taken froin the clear water bath are put into this bath remaining for
a short time, say ten or fifteen minutes, or until the next lot. of sheets or articles
from the water bath is ready. The action of this bath or solution of chlorides and
metallic oxides is to decompose the ferric salts, and neutralize free acid contained
in the pores of the iron after leaving the first bath of sulphuric (or muriatic) acid.
The ferric salts are infusiblo at the temperature of the metal bath, and unless they
are decomposed or removed they will remain in the iron and cause rust or other-
wise injure it by its subsequent decomposition after the metal coating has been
applied.
The sheets undried are then taken from this bath, and at once put into another
or flux bath composed of about equal volumes of water and any chlorides of the
organic or metallic bases whose salts are fusible at the temperature of the motal
bath. Instead of this bath I may use a bath composed in the proportion of one
gallon of water, two pounds of chloride of ammonium (sal ammonia), and one
gallon of dissolved chloride of zinc.
The surface of this last bath should be covered to a depth of two or three inches
with naphthaline oil or any other fusible substance capable of combining with
chlorine in a beated condition. As the sheets come from this last bath they aro
immorsed without drying in the usual manner into the bath of melted zinc or zinc
alloy when the desired coating is obtained.
This process of preparing the iron sheets or other articles is a valuable improve-
ment when the metal bath is zinc; and it is equally or more valuable when the
metal bath is of the alloy of zinc, tin, lead and nickel, or tin only, or iron coating
of any kind.
The improved alloy or compound metal made according to this Invention is
especially adapted for use as a metal bath into which iron sheets or other articles
are to be immersed and thereby coated so as to prevent oxidation. The proportions
may be somewhat variod, but the following is one of the best modes of compounding
my improved alloy, that is to say, I first melt in a large crucible in the proportion
from three to six ounces of nickel; into this crucible 1 pour from three to six
pounds of melted lead and mix the two metals thoroughly. This melted mixture is
then poured into a melting pot containing from ninety four to ninety eight pounds
of melted lead. Into this pot of nickel and lead I put about from fifty to seventy
five pounds of zinc and mix thoroughly; into this mixture I then melt and
thoroughly mix about twenty nine pounds of tin. This alloy thus made may be
cast into ingots and be remelted as desired, or it may be at once poured into the
metal bath or kettle. After the nickel and lead are melted and mixed together it
is better to introduce the zinc, and then the tin in ingots near the bottom of the
melted metal by dropping the pieces through a cylinder having its upper end above
the edge of the pot, and its lower end near the bottom of the pot. This mode of
introducing the zinc and tin facilitates a more thorough mixture.

page_text: By this Invention I am enabled to use a large quantity of lead in combination
with the zinc, tin and nickel, and yet have the alloy remain sufficiently electro
positive to the iron.
Metal coated by this Invention is as well or better protected against oxidation,
and its durability and tenacity is not injured to anything like the extent that
occurs when coated with zinc alone, and the coating itself is more flexible. The
metal bath of this alloy is efficient at a lower temperature than when zinc only is
used. When zine only is used the hot melted zinc acts upon the iron, in such a
manner as to dissolve from the iron a quantity of its surface, which combining
with a portion of the zinc becomes a beavy infusible dross chiefly consisting of iron
and zinc, which falls to the bottom of the metal bath, and interferes with the
proper action of the bath necessitating its constant removal, and is a source of
great waste as it is difficult to dispose of it at less than half its original cost. The
said improved alloy has a greater fluidity than zine only, and an efficient coating
can be made with a smaller percentage of metal than with zinc, so that less weight
is imparted to articles coated according to this Invention.
The combined action of my neutralizing bath and flux bath, so thoroughly cleans
the iron and frees it from infusible ferric salts and iron oxides as to insure a perfect
chemical union between the iron and the coating metal without the use of the
ordinary drying chamber and free muriatic acid.