A Process for Protecting Metallic Surfaces against Chemical and Atmospherical Action.
Year: 1896

page_text: PROVISIONAL SPECIFICATION.
A Process for Protecting Metallic Surfaces against Chemical and
Atmospherical Action.
1. BERNHARD POLITZER, of 10, Rudolfsplatz, Vienna I, in the Austrian
Empire, Machine Manufacturer to the Imperial and Royal Austrian Court, do
hereby declare the nature of this invention to be as follows:-
This invention relates to a method of coating the surface of objects made of
metals or alloys of metals with a layer or film which resists chemical and
atmospherical influences, and it has for its object to provide a protective coating,
which shall be thin, pliable, able to resist shocks and blows, perfectly smooth, of
simple and cheap manufacture, insoluble in most acids, fats and hydrocarbons,
and able to withstand temperatures up to 500° C. and firmly adhere to the metallic
surface.
According to my invention, the metallic surface which may be bright or
oxidized, is first made smooth. The surface is then coated with a thin layer of a
drying oil, such as linseed oil, nut oil, poppy oil, hempseed oil, castor oil, pumpkin-
seed oil, sunflower oil, pine-seed oil, fir-seed oil, cotton-seed oil, grapestone oil, etc.,
the coating being applied according to the nature of the article to be treated, either
by dipping and draining or by painting with a brush or the like.
The metallic article, coated with the thin layer of drying oil is then subjected
for a length of time varying from to 1 hour, to a temperature of from 200 to
350° C. in a suitable oven or the like whereby the oil is decomposed and con-
verted into a hard, shining, elastic mass which adheres to the metallic surface with
great force.
My process is very much less costly than the coating of metallic surfaces with
ebonite or other rubber containing material.
It is obvious that in carrying out the process, any drying oil or a mixture of
several of them may be used."
Furthermore the drying oil or mixture of drying oils to be used may have
added to it, in order to lasten its decomposition under the action of heat, any
of the well known siccatives, such as litharge, pyrolusite (brownstone), borate of
manganese, salts of linseed oil acid, etc. Or it may be impregnated with oxygen
or ozone.
In order to increase the adhesion of the drying oil, to the bright or oxidized
metallic surface before it is subjected to the action of heat some hard or soft resin
may be added to the oil before use. The subsequent prolonged subjection to a
temperature of from 200 to 300° C. reduces the resin to indifferent charcoal.
It will be obvious that any suitable colouring matter can be added to the oil
without altering the process.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.

page_text: A Process for Protecting Metallic Surfaces against Chemical and
Atmospherical Action.
I, BERNHARD POLITZER, of 10, Rudolfsplatz, Vienna I, in the Austrian
Empire, Machine Manufacturer to the Imperial and Royal Austrian Court, do
hereby declare the nature of this invention and in what manner the saine
is to be performed, to be particularly described and ascertained in and by the
following statement :-
This invention relates to a method of coating the surface of objects made of
metals or alloys of metals with a layer or film, which resists chemical and
atmospherical influences, and it has for its object to provide a protective coating,
which shall be thin, pliable, able to resist shocks and blows, perfectly smooth,
of simple and cheap manufacture, insoluble in alcohol, ether, most acids, fats and
hydrocarbons, and able to withstand temperatures up to 500° C. and firmly adhere
to the metallic surface.
According to my invention, the metallic surface, which may be bright or
oxidized, is first made smooth. The surface is then coated with a thin layer of
a drying oil, such as linseed oil, candle-nut oil, nut oil, poppy oil, hempseed oil,
castor oil, pumpkin-seed oil, sunflower oil, pine-seed oil, fir-seed oil, cotton-seed oil,
grapestone oil, etc., the coating being applied, according to the nature of the article
to be treated, either by dipping and draining, or by painting with a brush or
the like.
The metallic article, coated with the thin layer of drying oil, is then subjected
for a length of time varying from to 1 hour, to a temperature of from 200° to
400° C. in a suitable oven or the like, whereby the oil is decomposed and converted
into a mixture of anhydride of linoleic acid (C32 H 03) and of linoxine (C32 HO¹¹),
forming a continuous, hard, shining, elastic film which adheres to the metallic
surface with great force.
In
I am aware that coatings derived from drying oils have been made on metallic
articles heretofore, but the oil was either used as a varnish and allowed to dry at
ordinary temperatures, or the coated article was heated to a red heat, as is the
case when blackening small iron objects such as nails, buckles, tacks, screws.
the first case, the film obtained consists of the glycerides of linoleic acid and of
the other fatty acids contained in the oil, and it is consequently easily soluble in
alcohol, ether and hydrocarbons and is destroyed by the action of steam. In the
second case, when the drying oil is heated to a temperature above 400° C., the
anhydride of linoleic acid and the linoxine are decomposed with separation of
carbon and the hydrocarbons evolved in statu nascendi give rise to the formation
of carbides of the metal treated. The layer of carbon and carbides thus formed is
not a continuous film and it is destroyed by acids and other chemical agents.
From the foregoing statements it is seen that my invention is based on the fact
first observed by me that thin layers of drying oils, when heated to a temperature
between 2000 and 400° C. yield a continuous film of great resistance, whilst when
they are heated to temperatures below 200° C. or above 400° C. other compounds
are obtained which do not possess the valuable properties referred to.
My process is very much less costly than the coating of metallic surfaces with
ebonite or other rubber containing material.
It is obvious that in carrying out the process any drying oil or a mixture of
several of them may be used.
Furthermore, the drying oil or mixture of drying oils to be used may have added
to it, in order to haster its decomposition under the action of heat, any of the well

page_text: known siccatives, such as litharge, pyrolusite (brownstone), borate of manganese,
salts of linoleic acid, etc. Or it may be impregnated with oxygen or ozone.
In order to increase the adhesion of the drying oil to the bright or oxidized
metallic surface before it is subjected to the action of heat, some hard or soft resin
may be added to the oil before use. The subsequent prolonged subjection to a
temperature of from 200° to 400° C. reduces the resin to indifferent carbon.
It will be obvious that any suitable colcuring matter can be added to the oil
without altering the process.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. A process for protecting metallic surfaces against oxidation by chemical and
atmospherical action, the said process consisting in first coating the metallic
surface with a thin layer of a drying oil or mixture of drying oils, and then
subjecting the metallic article thus coated, for a period of from a half to one hour
to a temperature between 2000 and 400° C., substantially as described.
2. A process for protecting metallic surfaces against oxidation by chemical and
atmospherical action, the said process consisting in first coating the metallic
surface with a thin layer of a drying oil or mixture of drying oils, previously
treated with a known siccative, oxygen or ozone, and then subjecting the metallic
articles, thus coated for a period of from a half to one hour, to a temperature
between 2000 and 400° C. as set forth.
3. A process for protecting metallic surfaces against oxidation by chemical and
atmospherical action, the said process consisting in first coating the metallic
surface with a thin layer of a drying oil or drying oils, wherein some resin has
previously been dissolved, and then subjecting the metallic article thus coated, for
a period of from a half to one hour, to a temperature between 200 and 400° C. as
hereinbefore described.
4. A process for protecting metallic surfaces against oxidation by chemical and
atmospherical action, the said process consisting in first coating the metallic
surface with a thin layer of a drying oil or drying oils, previously treated with
a known siccative, or oxygen or ozone, and wherein some resin has been dissolved,
and then subjecting the metallic article thus coated, for a period of from a half to
one hour, to a temperature between 200 and 400° C. as set forth.
Dated this 17th day of February 1897.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.