Improvements in and connected with Carbonaceous Compounds.
Year: 1892

page_text: Date of Application, 7th Oct., 1892
Complete Specification Left, 4th July, 1893-Accepted, 26th Aug., 1893
PROVISIONAL SPECIFICATION.
Improvements in and connected with Carbonaceous Compounds.
Communicated from abroad by EDWARD G. ACHESON, of Monongahela City,
State of Pennsylvania, United States of America, Electrician.
I, PHILIP MIDDLETON JUSTICE of 55 and 56, Chancery Lane in the County
of Middlesex, Fellow of the Chartered Institute of Patent Agents, do hereby
declare the nature of this invention to be as follows:-
This invention relates to the production of artificial crystalline carbonaceous
materials, having the properties bereinafter more particularly set forth, and the
invention practically consists in the various processes and sub processes and in the
products of said processes as hereinafter more particularly set forth whereby
carbonaceous materials are treated in various ways, and carbonaceous products
produced which have the characteristics described, which carbonaceous products may
be designated under the general term "carborundum.”
The primary object of the invention is to produce a carbonaceous material which
shall have certain properties which render it useful as a substitute for diamonds,
bort, and other abrasive material, and which may in a certain sense be termed
artificial diamonds, and while I shall hereinafter describe in a general way the
characteristics of the products and the methods and means whereby they are pro-
duced, it is to be understood that I do not limit myself to the particulars set forth.
I have discovered that carbonaceous materials may be treated in connection with
other materials, and subjected to the action of heat, preferably that produced by
an electric current in such a manner that as a result, a crystalline carbonaceous
material is produced, which is a practical substitute for diamonds in their mechanical
applications, as well as for corundum in its various forms, and for other crystalline
materials.
In carrying out my invention, I take some carbonaceous material, preferably
that which is as pure carbon as practicable, together with silica, metals of the
alkaline earths or some earthy metal such as oxide of aluminium, oxide of silicon,
lime, etc., and mix these ingredients in proper proportion, and subject them to the
action of an electric current of sufficient strength and for a sufficient time, until the
crystalline carbonaceous material which I have termed "carborundum" is produced.
In practice I find it advisable to use some material to act as a flux or to prevent
the oxidation of the carbon, such as salt, alum, or equivalent material.
I have found by experiment that as a carbonaceous material, ordinary coke
produced from bituminous coal, or gas coke carbon, natural or artificial, give good
results, and the more nearly pure it is, the more satisfactory are the products.
This carbonaceous material is reduced to a proper state of sub division, and mixed
with a proper proportion of silica, metal of the alkaline earths, or earthy metal as
silica, alumina, or equivalent, and preferably with a flux such as common salt, when
the whole mass is properly sub divided and mingled thoroughly together.
I then subject the mixture to a high degree of heat and preferably make use of
what may be termed an electrical furnace. Any suitable furnace may however be
used, which is capable of withstanding the proper degree of heat, and the mixture
is placed in the furnace in such a manner as to allow the current of electricity to
be passed through the mass of material. Owing to the relatively high resistance
of the mass when first introduced into the furnace, I find it is sometimes desirable
to facilitate the passage of the current through the mass by introducing conducting
material, preferably by forming a core of such conducting material through the
mass, and I have found it convenient to use graphite in a loose or solid condition,
although other materials may be used; but this does not apparently interfere with
the process and the results as much as some other conductors.

page_text: "
On the passage of the current of the proper strength, which is preferably less at
the beginning of the operation than as it proceeds, (and consequently the current
should be capable of regulation) the mass becomes highly heated, and the flux is
melted, and the materials are subsequently brought into intimate association with
each other resulting in the crystalline products which I have termed " car-
borundum." During the process, chemical combinations and decompositions take
place, resulting in the production of gases, vapors, and volatile salts which are
permitted to escape from the furnace leaving in the furnace as products of the
process graphite, amorphus carbon, and "carborundum," while as a residue a
portion of the charge remains only partially converted, representing the various
stages of the conversion, and which Day form a portion of another charge.
The proportions and character of the chrystalline substance produced depend
upon many circumstances and incidents relating to the process, such as the strength
of the current the duration of the operation, the character of the materials used, and
the like. The crystalline substance is generally found in a zone surrounding the
graphite core.
As one convenient form of carrying out the process, I take of the pure carbon,
say 50 per cent., of the silica or alumina 25 per cent., and salt 25 per cent. by weight.
The strength of the current depends upon many conditions, such as the amount of
material, the characteristics thereof, and the rapidity with which the process is to
be carried out.
When the process is complete, the products are removed from the furnace and
separated, the "carborundum" being freed from the graphite and other impurities,
and broken into small pieces, which may be boiled and washed by decantation, and
subsequently dried by heat. It can then be graded into different size crystals by
sifting, or powdered by stamping machines and separated into different grades of
powder by floating in water, and other well known means, and collected and dried
ready for the market.
The crystalline substance which have termed "carborundum" as it is produced
in the first instance, appears to the eye very brilliant, and usually of a dark colour,
the colour depending to a large degree upon the materials used. The crystals do
not appear to be regular, but resemble pieces of bort, the general form of the
crystals being octohedral, although other well defined forms may be observed.
Many of these crystals are opaque, but some are transparent and colourless and
others are of various colours. The crystals are extremely hard and highly refrac-
tive, withstanding, for a long time at least, an oxygen blast, and are insoluble in
most if not in all of the ordinary solvents.
When carbon and silica are used in producing the "carborundum," it appears on
analysis, that it is represented by the formula ŠiC, and that the product is a true
crystalline combination of silicon and carbon.
"
The "carborundum in its crystalline or powdered form is adapted for many
and various uses, which need not be fully set forth, but it will probably be found to
be a practical substitute for diamond powder and bort in cutting diamond and other
gems. It may also be used in various ways as an abrasive material for optical
purposes, dental work, grinding valves, and may be prepared by forming into
wheels, discs, cloth or paper and other convenient forms for use. One of the most
important uses will probably be in connection with electric lamps forming the light
giving body or incandescent portion of the lamp, as its peculiar properties should
make it eminently fit for these purposes.
While I have thus described and set forth the general principles of the invention,
and the general characteristics of the new products, it will be understood that the
details may be varied or changed in many ways in carrying out the process, in the
materials used, and in the characteristics of the results produced, and I do not limit
myself in any of these particulars, as experiments may prove that other materials
may be satisfactorily employed, in carrying out the main objects of the invention.
Dated the 7th day of October 1805

page_text: COMPLETE SPECIFICATION.
Improvements in and connected with Carbonaceous Compounds.
A communication from abroad by EDWARD G. ACHESON, of Monongahela City,
State of Pennsylvania, United States of America, Electrician.
1, PHILIP MIDDLETON JUSTICE, of 55 and 56 Chancery Lane, in the County
of Middlesex, Fellow of the Chartered Institute of Patent Agents, 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:-
My invention relates to the production of artificial crystalline carbonaceous
materials, and it has for its object to produce an artificial crystalline substance
having the properties hereinafter more particularly set forth, and my invention
consists in the various processes and products of said processes substantially as
hereinafter more particularly set forth, whereby carbonaceous materials are treated
and carbonaceous products produced which have the characteristics described, which
carbonaceous products I have designated under the general term carborundum.
The primary object of my invention is to produce a carbonaceous material which
shall have certain properties which render it useful as a substitute for diamonds,
bort, and other abrasive material, and while I shall herein describe in a general
way the characteristics of the products and the methods and means whereby they
are produced, it is to be understood that I do not limit myself to any of the
particulars set forth, as I intend to cover and claim broadly the new crystalline
carbonaceous materials whether produced by the particular processes or methods
set forth, or by any substantially equivalent methods, and for all purposes to which
it may be applied.
I have discovered that carbonaceous materials in connection with certain other
materials may be subjected to the action of heat, preferably that produced by an
electric current in such a manner that as a result, a crystalline carbonaceous
material is produced, which is a practical substitute for diamonds in their
mechanical applications, as well as for corundum in its various forms, and other
crystalline materials.
In the accompanying drawing I have shown one form of furnace which may be used.
In carrying out my invention, I take some carbonaceous material, preferably that
which is as pure carbon as practicable, together with silica, or equivalent as silicate
of alumina or of lime, &c., and mix these ingredients in proper proportion, and
subject them to the action of an electric current of sufficient strength and a
sufficient length of time, until the crystalline carbonaceous material is produced.
In practice I find it advisable to use some material to act as a flux, such as common
salt or equivalent material.
I have found by experience that as a carbonaceous material, ordinary coke
produced from bituminous coal, or gas coke carbon, natural or artificial, give good
results, and the more nearly pure it is, the more satisfactory are the products.
This carbonaceous material reduced to a proper state of sub-division, and mixed
with a proper proportion of silica, silicate or alumina or equivalent, and preferably
with a flux such as common salt, when the whole mass is properly sub-divided and
mingled thoroughly together. I then subject the mixture to a high degree of heat
and preferably make use of what may be termed an electrical furnace. Any
suitable furnace may be used, which is capable of withstanding the proper degree
of heat, and the mixture is placed in the furnace in such a manner as to allow the
current of electricity to be passed through the mass of material. Owing to the
relatively high resistance of the mass when first introduced into the furnace, I find
it is sometimes desirable to facilitate the passage of the current through the mass
by introducing conducting material, preferably by forming a core of such conducting
material through the mass, and I have found it convenient to use graphite in a

page_text: loose or solid condition, although other materials may be used, but this does
not apparently interfere with the process and the results as much as some other
conductors.
Thus in the accompanying drawings, A represents a cross section of any suitable
furnace, which may be made of fire-brick or other material having the electrodes B, C,
extending through the walls of the furnace, and connected to a dynamo or other
electric generator D, the mixture M, being placed within the furnace, and when the
conducting core is used, it may be placed as indicated at E, between the ends of the
electrodes. On the passage of the current of the proper strength, which is
preferably less in the beginning of the operation than as it proceeds, and
consequently the current should be capable of regulation, the mass becomes highly
heated, and the flux is melted, and the materials are subsequently brought into
intimate association with each other, resulting in the crystalline carbonaceous
products. During the process, chemical combinations and decompositions take
place, resulting in the production of gases, vapors, and volatile salts which are
permitted to escape from the furnace leaving in the furnace as products of the
process graphite, amorphous carbon, and the carbonaceous product I have termed
carborundum, while as a residue a portion of the charge remains only partially
converted, representing the various stages of the conversion, and which may form a
portion of another charge.
The proportions of the crystalline substance, produced, depend upon many
circumstances and incidents relating to the process which need not be fully set forth.
The crystalline substance is generally found in a zone surrounding the core, and the
extent of this zone, and the character of the crystalline material depends upon
many things, such as the strength of the current, the time of operation, the character
of the material used, and other conditions.
As one convenient form of carrying out the process, I take of the pure carbon,
say fifty per cent., of the silica or silicate of alumina twenty five per cent., and
common salt twenty five per cent. by weight. The strength of the current depends
upon many conditions, such as the amount of material, the characteristics thereof,
and the rapidity with which the process is to be carried out. When the process is
complete, the products are removed from the furnace and separated, the
carbonaceous materials are freed from the graphite and other impurities, and
broken into small pieces, and may be boiled and washed by decantation, and sub-
sequently dried by heat. It can then be graded into different size crystals by sifting,
or powdered by stamping machines and separated into different grades of powder
by floating in water, and other well known means, and collected and dried ready
for the market. The crystalline substance as it is produced in the first instance,
appears to the eye very brilliant, and usually of a dark color, the color depending
to a large degree upon the materials used. The crystals do not appear to be
regular, but resemble pieces of bort, the general form of the crystals being
octohedral, although other well defined forms may be observed. Many of these
crystals are opaque, but some are transparent and colorless, and others are of
various colors. The crystals are extremely hard and highly refractive, with-
standing, for a long time at least, an oxyhydrogen blast.
When the mixture consists of carbon, silica and chloride of sodium in about the
proportions indicated, I have found that the resulting product which I have
termed carborundum shows as an average sample, the following analysis :

page_text: When the mixture is composed of carbon, clay (silicate of alumina) and chloride
of sodium in about the proportions specified, an analysis of the product is as
follows:
It thus appears that the material which I have designated as carborundum is
practically a new compound hitherto unknown' to chemistry, and in its purity
is represented by the formula SiC, and may be known under the chemical term of
silicide of carbon or carbide of silicon.
The new carbonaceous material in its crystalline or powdered form is adapted for
many and various purposes which need not be fully set forth, but it has been found
to be the practical substitute for diamond powder and bort in cutting diamonds and
other gems.
It can also be used in various ways as an abrasive material for
optical purposes, dental work, grinding valves, and may be prepared by forming
into wheels, discs, cloth or paper and other convenient forms for use.
One of the most important uses is in connection with electric lamps forming the
light giving body or incandescent portion of the lamp, as its peculiar properties
make it eminently fit for these purposes.
While I have thus described and set forth the general principles of my invention,
and the general characteristics of my new product, it will be understood that the
details may be varied or changed in many ways in carrying out 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 (as communicated to me by
my foreign correspondent) I declare that what I claim is :-
1. The within described product being silicide of carbon SiC.
2. The within described crystalline product containing a compound of silicon and
carbon and being characterized by great hardness, refractability and infusibility.
3. The within described crystalline compound containing silicide of carbon SiC,
and being characterized by its great hardness, refractability and infusibility.
4. The within described process of making a hard and refractive compound of
carbon and silicon which consists in subjecting materials containing carbon and
silica, free or combined to the action of an electric current.
5. The within described process of making a hard and refractive compound of
carbon and silicon, which consists in subjecting materials containing carbon, silica,
free or combined and a suitable flux to the action of an electric current."
6. The within described process of making a hard and refractive compound of
carbon and silicon which consists in subjecting materials containing carbon, silica,
free or combined, a suitable flux and a core of conducting material to the action of
an electric current.
7. The within described process of making a hard and refractive compound of
carbon and silicon, which consists in subjecting materials containing carbon, silica,
free or combined, and a metallic chloride to the action of an electric current.
8. The within described process of making a hard and refractive compound of
carbon and silicon, which consists in subjecting materials containing carbon, silica,
free or combined and a chloride of an alkali metal to the action of au electric
current.
9. The within described process of making a hard and refractive compound of

page_text: carbon and silicon, which consists in subjecting materials containing carbon, silica,
free or combined, a chloride of an alkali metal and a core of conducting material
to the action of an electric current.
CTI
1000
PHILIP M. JUSTICE.