Abstract: A composite electrode for electrochemical processing having improved high temperature properties, and a process for making the electrode by combustion synthesis. A composition from which the electrode is made by combustion synthesis comprises from about 40% to about 90% by weight of a particulate or fibrous combustible mixture which, when ignited, is capable of forming an interconnected network of a ceramic or metal-ceramic composite, and from about 10% to about 60% by weight of a particulate or fibrous filler material capable of providing the electrode with improved oxidation resistance and maintenance of adequate electrical conductivity at temperatures above 1000.degree. C. The filler material is molybdenum silicide, silicon carbide, titanium carbide, boron carbide, boron nitride, zirconium boride, cerium oxide, cerium oxyfluoride, or mixtures thereof.

Abstract: An adherent protective coating of a refractory material is produced on the surface of carbonaceous, refractory, ceramic, metallic or other materials serving as components of electrolytic cells operating at high temperature, by applying to such surfaces a well chosen micropyretic reaction layer from a slurry, which when dried is ignited to initiate a self-sustaining micropyretic reaction, along a combustion front, to produce condensed matter forming such refractory protective adherent coating. The slurry is preferably applied in several layers, the first layer(s) to facilitate adherence and the last layer(s) to provide protection, and may contain some preformed non-reactant materials. The electrolytic cells whose components require such coatings are especially those operating at high temperature with a molten salt electrolyte, particularly those for the production of metals, aluminium being the most important.

Abstract: A cell for the electrowinning of aluminum from molten salts has a cell bottom lining consisting partly of a refractory mass (4 ) and partly of carbon bodies (5). At least 30% and preferably 50% or more of the cell bottom area is occupied by the refractory mass (4). The carbon bodies (5) are level with the refractory mass (4) or are recessed therein.

Abstract: A cell for the electrowinning of aluminum from molten salts has a cell bottom lining consisting partly of a refractory mass (4) and partly of carbon bodies (5). At least 30% and preferably 50% or more of the cell bottom area is occupied by the refractory mass (4). The carbon bodies (5) are level with the refractory mass (4) or are recessed therein.

Abstract: An aluminum production cell with a non-conductive cell bottom composed predominantly of alumina (1) has a plurality of vertical current collector plates or posts (3), e.g., of steel protected at their upper ends by a carbon body (4), e.g., a plate, slab or cap which contacts the cathodic pool of molten aluminum (10).

Abstract: A method of electrowinning a metal by electrolysis of a melt containing a dissolved species of the metal to be won using a non-consumable anode having a metal, alloy or cermet substrate and an operative anode surface which is a protective surface coating of cerium oxyfluoride preserved by maintaining in the melt a suitable concentration of cerium, is characterized by using an anode provided with an electronically conductive oxygen barrier on the surface of the metal, alloy or cermet substrate. The barrier layer may be a chromium oxide film on a chromium-containing alloy substrate. Preferably the barrier layer carries a ceramic oxide layer, e.g. of stabilized copper oxide which acts as anchorage for the cerium oxyfluoride.

Abstract: A bipolar electrode for electrowinning aluminum or other metals by electrolysis of a molten salt electrolyte containing a dissolved compound of the metal to be won comprises an anodic and a cathodic surface which are both preserved during operation by dissolution of small amounts of a substance in the electrolyte which is capable of being deposited on either surface at a rate compensating the corrosion thereof during electrolysis. The anodic surface is for example cerium oxyfluoride and the cathodic surface cerium hexaboride, both surfaces being preserved by addition of cerium compounds, such as oxides, fluorides, hydrides etc. to the melt. The cathodic surface may also include titanium diboride on top of or together with cerium hexaboride.

Abstract: A composite material comprises a body, e.g., a slab, of a fused refractory oxycompound (3) having a multiplicity of discrete inclusions such as lumps (1) of an aluminum-wettable RHM in its surface. These bodies are especially useful as aluminum-wettable but non-current carrying components of aluminum reduction cells.

Abstract: A ceramic/metal composite material comprises a surface ceramic coating comprising an oxidized alloy of copper stabilized by being in solid solution with nickel oxide or manganese oxide on a substrate which is an oxidation resistant alloy essentially devoid of copper or any metal which oxidizes more readily than copper. The composite is made by oxidizing a copper-based alloy on a substrate and simultaneously oxidizing the substrate surface to form an oxygen-barrier interface, for example a chromium oxide layer formed on an alloy of chrominum with nickel, iron and/or cobalt. The composite may be used as anode substrate for a cerium oxyfluoride coating used in aluminum electrowinning.

Abstract: A non-consumable anode of the type comprising an oxide ceramic coating on a metal substrate, for molten salt electrolysis, namely the electrowinning of metals such as aluminum, has an electronically-conductive oxygen barrier layer between the oxide ceramic coating and the substrate, the oxygen barrier layer containing chromium oxide. Usually, the oxygen barrier layer is a surface film integral with a chromium-containing alloy substrate, comprising 10 to 30% by weight of chromium, 55 to 90% of nickel, cobalt and/or iron and up to 15% of aluminum, titanium, zirconium, yttrium, hafnium or niobium. The ceramic oxide coating may comprise copper oxide in solid solution with at least one further oxide; nickel ferrite; copper oxide and nickel ferrite; doped, non-stoichiometric or partially substituted spinels; or rare earth metal oxides or oxyfluorides.

Abstract: The present invention provides a ceramic/metal composite material comprising cerium/aluminum mixed oxides as the ceramic phase and an alloy or intermetallic compond of cerium and at least one of aluminum, nickel, iron and cobalt as the metal phase. The ceramic phase may comprise interengaged crystal lattices of ceria and alumina. The material may be a self-sustaining body which may be used as substrate for a dimensionally stable anode in molten sale aluminum electrowinning cells, coated with a protective layer of cerium oxyfluoride in situ during electrolysis in molten cryolite containing cerium ions.

Abstract: The invention refers to a method and a device for varying the application amount of a coating agent at the blade coating of a moving material web (24,40,51), preferably a paper web, by corresponding control of the engagement pressure of the coating blade (20,43,50,68) against the web (24,40,51) which exhibits a coating agent surplus. The web is supported by a support, preferably a rotating support roller (25,41), and the blade is along one of its longitudinal sides clamped in a blade holder (21,44,49,69), moreover the blade is initially, with a certain force and thereby in an obtained arcuate shape, brought, with the opposite longitudinal side thereof, into engagement with the web, in a certain given angle between blade tip and web, and with a thereby defined engagement area.

Abstract: There is disclosed a method of and apparatus for producing a wear-resistant coating on a thin metallic strip, for example for the manufacture of coating scrapers for paper webs. After preparatory surface treatment the strip is passed longitudinally through a coating zone in which coating material in a molten state is sprayed onto the strip by a coating unit as the strip passes. The wear-resistant coating is built up in steps by the application of several coating layers one on top of the other, each being applied during a respective pass of the strip through the coating zone. The strip speed and the capacity of the coating unit are adjusted in relation to each other so that the heat supplied to the carrier material by each coating layer applied will be so slight in relation to the thermal capacity of the carrier material that the temperature increase in the carrier material does not cause any change in the physical properties of the carrier material.

Abstract: A method and apparatus for coating both sides of a moving web, such as a paper web, with the same coating material on both sides by feeding the web downwardly between a rotating support roller and a coating blade directed against said roller. One side of the web is partially wrapped around said roller and a first excess of coating material intended for the web side facing said roller is applied to the roller before or at the point of contact between said web and the roller. A second excess of coating material is applied to the other side of the web by feeding the web through a dam of coating material arranged below said contact point--in the moving direction of the web--said dam being formed substantially between said coating blade and holder and the said other side of the web. The excess coating material is laterally expressed in said dam beneath the top level thereof.

Abstract: A continuous process for applying a coating to both sides of a paper web in which the web is fed at a speed of at least 400 meters per minute through the nip formed between a rotating applicator roll and an elastically yielding blade. A coating composition is fed into the sumps formed on each side of the web at the nip at a rate such that the amount of coating material applied to the web, calculated as the total of both sides of the web, exceeds 14 grams per square meter. The viscosity of the coating composition is maintained at 400 to 2000 centipoises and the web is withdrawn from the nip so that it is bent away from the applicator roll over the edge of the blade at an angle of between 8.degree. and 12.degree. to the tangient to the roll at the nip, thus reducing or eliminating the formation of mist downstream of the nip.

Abstract: Apparatus selectively convertible to perform one or more coating operations on a web of paper or the like comprises a fixed rotatable roller, a coating blade movable into and out of coating relation with the surface of the fixed roller and cooperating with a dam of coating material to coat a web as it passes through the nip between the coating blade and the fixed roller, and a second movable roller movable into and out of nip forming relation with the fixed roller with provision for adjustment of pressure in the nip and adapted to cooperate with a dam of coating material to coat a web as it passes through the nip between said rollers, said movable roller also being adapted alternatively to receive coating material and to transfer it to the fixed roller to coat one side of a web as it runs over the latter.

Abstract: In a method of treating a surface such as a paper web with a treating agent, the treating agent is foamed under pressure and delivered via a passsageway to an application zone so as to come into close proximity with the surface to be treated which may be moved continuously past the application zone. A constriction, upstream in the direction of foam flow, of the passageway causes a pressure drop in the body of the foam causing bubbles of the foam to burst adjacent the surface, being treated whereby the treating agent is applied to the surface.

Abstract: A method and apparatus for coating at least one face of a moving web, such as a paper web, in which the web is fed longitudinally at a speed in excess of 400 meters per minute between a movable support and a blade forming, with the movable support, a nip. The blade has a bevel at the point of contact with the web, and an excess of coating material is applied at one side of the web in the nip, the coating material having a dryness content exceeding 60% and/or a viscosity exceeding 1500 cp. The angle of the blade is controlled so that it extends at most 20.degree. to the web and the bevel width, as measured in the direction of movement of the web, is at most 0.05 centimeters. Preferably, the blades are urged against the web with a force not exceeding 2 kgf per centimeter width of web.

Abstract: A method for applying a coating composition onto a moving paper web, in which the web is supplied with an excess of said coating composition. The web is passed tightly over a lower slot in a container, which by means of vacuum, is kept filled with the coating composition. A flexible blade is arranged to remove the excess coating composition and to uniformly regulate the final thickness of the coating and said removed excess coating is recirculated to the container for further use.

Abstract: A method and apparatus for applying a coating composition onto a moving web especially a paper web, in which an excess of said coating composition is applied to said web. The web thereafter passes smoothing means to uniformly regulate the final thickness of the coating and simultaneously to remove the excess coating composition. This smoothing operation is performed under an adjustable partial vacuum. The removed excess coating composition is recirculated without being mixed with the coating composition within the application area and is mixed with fresh coating composition before reuse within the process.