Improvements in Electric Conducting Sheaths or Coverings for Articles of Ceramic or Pulverulent Materials.
Year: 1899

page_text: Date of Application, 31st Oct., 1899-Accepted, 3rd Mar., 1900
Improvements in Electric Conducting Sheaths or Coverings for
Articles of Ceramic or Pulverulent Materials.
We, DESIDER SZANKA, Electrical Engineer, of Nagy-Rókus ŭ 35, and GANZ &
COMPANY EISENGIESSEREI UND MASCHINEN-FABRIKS ACTIEN-GESELLSCHAFT," of
II, Ganz-utcza, both in Budapest, in the Kingdom of Hungary, 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:-
The present invention relates to an electric-conducting sheath or covering of
such a nature that it may combine with the article to be covered
The articles to be covered may be ceramic or like wares and in this case the
conducting sheath or covering may be applied to such articles either before or
after the baking of the same or the articles may be composed of powdered
substances such as are used in connection with certain electric-resistances.
The material of the sheath or covering should be of such a nature that it will
combine either chemically or mechanically with the article, and at the same
time form a good electric conductor This result is attained by forming the
sheath or covering from metallic dust or metallic oxide such as iron, ironoxide,
nickel and so forth, or a mixture thereof which 18 capable of combining with
the material of the article to be covered, or by admixing with the conducting
material, such as metal or metallic oxide, a binding substance such as clay, silicic
acid, gypsum or the like which is adapted to combine with the constituent parts
of the article, that is to say, with the non-conducting parts, or with the metallic
or metalloid portions of the same, or with both the latter
In cases where it is intended to prevent the oxidation of the conducting
material as foi example when finely divided nickel dust is used, or when it is
desued to reduce the metallic oxides contained in the mixture, the material of
the sheath or covering as well as the material forming the article are mixed with
a reducing agent such for example as carbon
The material or mixture intended to form the sheath or covering is applied
to the article either in separate pieces or in the form of a powder, plates or in
any other convenient manner according to whether the article to be covered 18
formed from a powder or from plastic material
Articles formed of pulverulent substances pressed into shape or dried are
covered by simply applying the coating material by painting or pressing-on the
same or by mixing the said material with the outer portion of the material of
the article. If in connection with articles formed by hand or by means of 1olleis
or by a wet process it is found that the mere application or sticking-on of the
covering material does not give good results it is advisable to work the covering
material into the external surface of the article.
To articles of strongly compressed or dried material the covering substance
18 applied in a wet state or mixed with an appropriate binding agent such as
1singlass or the like, or it may be compressed upon the same as a powder
Articles of ceramic ware are provided with a sheath or covering in a similar

page_text: manner and are then subjected to a baking or careful drying process so as to
form a more intimate and permanent connection with the article.
Articles produced by pressure, for example in a mould or press may be provided
with a sheath or covering by introducing the conducting mixture simultaneously
with the material from which the article 18 to be made into the said press in
such a manner as to cause the covering substance at the outlet nozzle, to be
evenly distributed over the outer surface of the said article, say upon the external
surface or at the ends of tubes, rods or bars and so on
The sheath or covering may be formed of several layers should this be required
for the purposes of strength or stiffness The conditions of an intimate con-
nection between the various layers are the same as in the case of a single sheath
or covering.
The drying baking and shrinking as well as the degree of temperature of the
article and its coating should not differ to such an extent as to cause strains m
the middle lavei To this end the shrinkage of the article and that of the sheath
or covering are so regulated as to alter the conditions of the substances in contact
with each other or an admixture of non-contacting material such as chamotte-
powder or a more or less calcined substance may be employed for this purpose
The sheath or covering forming the subject of the present invention is of great
impoítance for theostats of ceramic or pulverulent mixtures
One of the chief objections to the practical use of such heostats is that the
contacts are often formed defective Consequently owing to the girat specific
resistance of the materials of the heostat the external conducting portion or
sheath thereof becomes over heated, while moreover beneath the conducting
portions there are formed microscopic voltaic-aics which destroy the material of
the rheostat thus increasing the resistance and rendering the rheostat useless
By providing such rheostats with a sheath or covering according to the fore-
going description and connecting the electrodes or brush-contacts of the electrodes
with the said conducting sheath or covering instead of duectly with the material
of the rheostat, the disadvantages previously mentioned will be obviated and
results may be obtained which it is impossible to effect with a coating deposited
by electrolysis upon the material forming the theostat
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that
what we claim 18.-
1 An electric conducting sheath or covering for articles produced from com-
pressed ceramic or pulverulent materials, consisting of an electric conducting
material or metallic compound, or a mixture of both, adapted to form an intimate
mechanical or chemical combination with the material of which the article 18
composed and converted into a good conductor by the inter-action of the con-
stituent materials
2 A modified form of the sheath or covering claimed in Claim 1, characterized
by the addition to the material for forming the sheath or covering of a binding
or a reducing agent or a mixture of both
Dated this 31st day of October 1899
HASELTINE, LAKE & Co,
45, Southampton Buildings, London, WC,
Agents for the Applicants