UNITED STATES PATENT orrron. "
THOMAS WATTS cosLETT, 0E BIRMINGHAM, ENGLAND.
TREATMENT 0E I'noN on STEEL To" PREVENT THE oxnm'rron on nusTrNe TnEnEoE.
1,007,069.
No Drawing.
Speci?cation of Letters Patent.
Patented Oct. 31, 19711.
Application ?led Kevember 25, 1910. Be'rial No.- 594,108.
Tooll whom it may concern."
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- ‘Be it known that I, THOMAS WAT'rs Cos
thereof a 1} oz. or "less of the concentrated
LETT,'a subject of the King of Great Brit
solution as and'when required. As an'illus
land, have invented certain new and use
dilute solution, yielding satisfactory results,
of the extent to which the concen~
ain, residing at 70—74\Vittoria street, B11‘ tration solution
may be diluted, it may be '
mingham, in the county of Warwick, Eng ~.trated
stated that when 10 cubic centimeters of a 61)
ful Improvements Relating to the Treat
'ment of Iron or Steel to Prevent the Oxi
10
15
20
were mixed with 10 cubic. centimeters of a
saturated solution of pure sodium chlorid,
dation of Rusting Thereof, of which the vthe
neutralization of the mixture was ef
following is_ a speci?cation.
footed/by
6.7 cubic centimeters of decinor
This invention relates to the treatment of mal sodium hydrate solution. Using the
iron or steel and has reference to the kind factor .00486, this titration indicates that
of.treatment by which .there is, imparted
dilute solution contained .32562 grams
to the iron or steel.‘ surfaces a protective the
‘of
free‘
per 100 cubic centimeters.
covering that renders the same capable of _ Underacid
certain
circumstances, it may be
resisting, or being unaffected by the action of advantage to treat
the iron or steel with
of, moisture or ot er oxidizing or “ rusting” a solution containing not only zinc phos
in?uences. '
phate but also iron phosphate which of
Acoording to this invention the iron or itself
a known agent for obtaining a pro
steel is subjected to the action of phosphoric tectiveiscoating
on iron or steel. In this case,
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75
acid in the presence of zinc or a suitable zinc iron ?lings or a suitable iron compound and
compound or to the action of a solution granulated zinc, or a suitable zinc com~
of the latter in phosphoric .acid or to pound, may be dissolved in‘ strong or dilute
the action of acidulous zinc
hosphate. phosphoric acid; if "dilute acid is used the
conveniently be used for this purpose, pounds'may be concentrated until a strong
80
short time,
90
Zinc, zinc - oxid or zinc phosp ate may dilute solution of the iron and zinc com
and the solution obtained by the. action _ solution is obtained.
In either case the
of the phosphoric acid upon the same is strong solution may be separated
from any
preferably made in a concentrated condi remaining solid matter and diluted
to any 85
30 tion. The concentrated solution obtained
~
desired
extent
or
be
applied
for
a
short
time
- may afterward be separated from any sedi direct to the surfac c 0 the iron or steel,
01'
ment or excess of zinc or‘ zinc compound to a surface upon which a deposit has al
that may be present ‘and then be applied ready
been obtained by the action of the
directly to the iron or steel articles for a dilute solution.
‘
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40
45
or be diluted with water to any ‘
The treatment‘ of the iron or steel with
desired extent before' the iron- or- steel phosphoric
acid and zinc or a suitable zinc
articles are immersed therein or treated with compound, or with a solution of zinc phos
it. Or the strong solution may- be applied phate
may be carried out in conjunction
direct to a surface on which a deposit has with known
methods of treating iron or
been obtainedby action of dilute solution.
steel 'for the production of a coating of
Phosphoric acid ________ __ 1 pint.
- Wate1'_‘_ _____________ ___,_‘_‘ 1 pint‘.
50
quently used direct, or diluted, if desired,-or
the aforesaid solution either concentrated or
Heat may or ma not be employed as an dilute of zinc in phosphoric acid may be
aid in dissolving t e solid portions of the,‘v added to the liquid contained in the vessel
‘in which the deposit of phosphate of iron
ingredients.
on the iron or steel is being effected.
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95
A suitable formula for preparing the con phosphate of iron. In this connection a
centrated solution-may be as follows com» strong
of zinc in phosphoric acid
prising the ingredients given in or about obtainedsolution
as
above
described may be added
the proportions stated :—
.
in sultable proportions to a strong solution 10.
Zinc _________ _'_ ________ __-6 oz.
I
of iron in‘ phosphoric acid and be subse
The »
In order to render the solution in diluted".v effect of the zinc‘ phosphate‘ solution on the
form, it is simply necessary to add 1 oz. surface of the ironor'steel
under treatment
of'the concentrated solution to each gallon would apparently be similar
to that- of 110
of water. For the purpose of renewing the phosphoric acid
.
on
metallic
zinc,
as necesé
dilu'te solution there is added to' each gallon sarlly a certain amount of zinc must
bedis
1,007,069
to a known ‘amount of phosphoric
solved to form‘ phosphate of zinc before any employed
acid
is
preferably
such that t e diluted
deposition is formed. The coating consists solution ?nally obtained
contains only com
essentially of normal zinc phosphate mixed paratively a small percentage
of free phos
with small amounts of normal ferrous phos
phoric
acid.
.
phate and free phosphoric acid. The latter
What I claim and desire to secure by Let
could, however, be reduced by more thorough ters
Patent of the United States is :—
washing. The normal ferrous phosphate is
10
no doubt obtained by the inter-action of the
free phosphoric acid with the metal treated.
Iron or steel that has already had a coating
of phosphate of iron formed upon it may
if desired be subjected to the action of the
zinc solution, or of phosphoric acid in pres
ence of zinc or a suitable zinc compound.
1. The treatment of iron or steel for pre
venting the oxidation or rusting thereof,
consisting in subjecting the same to the ac
45
tion of a zinc-containing solution of phos
phoric acid.
i
2. The treatment ofiron or steel for pre
venting the oxidation or rusting thereof,‘
consisting in subjecting the same to the ac 50
formation of the deposit on the iron tion of a zinc-containing solution of phos
p15 or The
steel or surface under treatment may be phoric acid of varying degreesof concen
accelerated by passin an electric current
through the dilute so ution which may be tration.
3. The treatment of iron or steel for pre
either in a hot or a cold condition. In
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the oxidation or rusting thereof,
adopting such a method of procedure the venting
consisting
in subjecting the same to the ac
passage of the electric current through the
bath containing the aforesaid solution is tion of a solution of zinc and iron phos
55
.
'
effected by the method ordinarily employed phate.
4:. The treatment of iron or steel for pre
by platers, with, for instance, iron anodes. venting the oxidation or rusting thereof,
Thus the electric current may be passed
in subjecting the same as the
through by connecting to the wire from the consisting
cathode to the action of a zinc-containing
positive pole‘ of an‘ electric battery or other solution of phosphoric acid through which
source of electricity a plate of iron or steel,
current is passed.
the metal intended for treatment being at anInelectric
testimony
whereof I a?ix my signature
tached by wire to the negative pole and in presence of two
witnesses.
thereby acting ‘as a cathode.
THOMAS
WATTS COSLETT.
Ortho-phosphoric acid or dissolved pyro
Witnesses:
‘
or meta-phosphoric acid may be employed
F. J. RAPsoN,
in the preparation of the zinc solution, and
T. SELBY WARDLE.
the proportion of zinc or zinc compound
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