摘要:
In rechargeable or primary electrochemical cells, hydrogen may evolve. The invention concerns the use of an auxiliary electrode material comprising manganese dioxide and a catalyst as the oxidant providing for the recombination of pressurized hydrogen, for example, the hydrogen being at pressures ranging from from substantially zero gauge pressure up to the relief pressure of the cell. The cell is a sealed cell having a manganese dioxide cathode, a zinc anode and aqueous electrolyte contacting both anode and cathode. The aqueous electrolyte may be alkaline or it may be ammonium chloride or zinc chloride, or mixtures thereof. The auxiliary electrode material, which may be mixed with the cathode material or be formed into a discrete auxiliary electrode, may optionally comprise a porous substrate, and in any event comprises MnO.sub.2 and a catalyst for the recombination of pressurized hydrogen with the MnO.sub.2. The substrate may be carbon black or graphite; the catalyst may be a metal, metal salt or metal oxide of elements such as lead, nickel, titanium, lanthanum, chromium, vanadium, tantalum and catalytically active alloys thereof. Most particularly, the catalyst may be silver, platinum, silver oxide, or silver dioxide.
摘要:
A screening implement used in repairing or mounting screens comprising a substantially planar substrate having on at least one side a coating of an adhesive having a peel force exceeding 50 grams/cm width as determined in the 180 degree peel adhesion test, a low water sensitivity thereby being suitable for weather or marine exposures, a high thermal stability over a temperature range from -60 to +60 degrees C., and means for creating a bond between said adhesive and a screen, said bond having a durability of not less than 6 months.A method for repairing defective screens whereby a screening implement as described above is affixed to replace a defective section of a screen removed from the screen. The screening implement may be covered by a releasable liner sheet. In use the releasable liner sheet is removed from the screening implement and the screening implement is affixed to a screen by the exposed adhesive.The adhesive screening implement can be made from a continuous strip and custom cut just before application, or can be precut to conform to a variety of designs and sizes.
摘要:
In rechargeable, electrochemical cells, oxygen may evolve on charge, overcharge or any reversal of polarity. The invention concerns an auxiliary, electrochemical, transfer electrode to catalyze the recombination of such oxygen with the anode mass. The auxiliary electrode may comprise a porous carbon bonded with PTFE, or it may comprise a zinc gel having graphite particles and/or metal-plated zinc particles--where the metal that plates the zinc particles may be copper, or may be any of cobalt, cadmium, nickel, or silver. The auxiliary electrode for rectangular electrodes as used in flat plate or jelly roll cells may have the catalytically active material PTFE bonded to the current collector. The cell is generally one having a zinc anode, a metal oxide cathode (usually manganese dioxide), and an aqueous alkaline electrolyte (usually potassium hydroxide) contacting both anode and cathode.
摘要:
A rechargeable alkaline electrochemical cell has a manganese dioxide cathode and a zinc anode. The cathode is mixed with graphite or other conductive carbon and a binder, and is contained by a metallic screen which also serves as an oxygen evolution catalyst. The screen also serves to contain the cathode in place as it tends to expand under use. A diaphram is provided to separate the cathode and anode; an alkaline electrolyte contains the cathode and anode, and the other components of the cell.
摘要:
In rechargeable or primary, electrochemical cells, hydrogen may evolve. The invention concerns the use of an auxiliary electrode material to catalyse the recombination of pressurized hydrogen, for example, the hydrogen being at pressures ranging from 5 to 15 psig up to pressure relief of the cell. The cell is a sealed cell having a metal oxide cathode, a zinc anode and aqueous, alkaline electrolyte contacting both anode and cathode. The auxiliary electrode material, which may be mixed with the cathode material or be formed into a discrete auxiliary electrode, comprises a porous substrate and a catlyst for the absorbtion of pressurized hydrogen by the electrolyte. The substrate may be carbon, graphite or metal. The catalyst may be carbon, catalytically active noble metals, salts and oxides of lead, nickel, titanium, lanthanum, chromium, tantalum and alloys thereof, and the metals or mixtures of carbon with the salts or oxides.
摘要:
Composite current collectors containing coatings of metals, alloys or compounds, selected from the group of Zn, Cd, Hg, Ga, In, Tl, Sn, Pb, As, Sb, Bi and Se on non-metallic, non-conductive or poorly-conductive substrates are disclosed. The composite current collectors can be used in electrochemical cells particularly sealed cells requiring a long storage life. Selected metals, metal alloys or metal compounds are applied to polymer or ceramic substrates by vacuum deposition techniques, extrusion, conductive paints (dispersed as particles in a suitable paint), electroless deposition, cementation; or after suitable metallization by galvanic means (electrodeposition or electrophoresis). Metal compound coatings are reduced to their respective metals by chemical or galvanic means. The current collectors described are particular suitable for use in sealed primary or rechargeable galvanic cells containing mercury-fee and lead-free alkaline zinc electrodes.
摘要:
Composite current collectors containing coatings of metals, alloys or compounds, selected from the group of Zn, Cd, Hg, Ga, In, Tl, Sn, Pb, As, Sb, Bi and Se on non-metallic, non-conductive or poorly-conductive substrates are disclosed. The composite current collectors can be used in electrochemical cells particularly sealed cells requiring a long storage life. Selected metals, metal alloys or metal compounds are applied to polymer or ceramic substrates by vacuum deposition techniques, extrusion, conductive paints (dispersed as particles in a suitable paint), electroless deposition, cementation; or after suitable metallization by galvanic means (electrodeposition or electrophoresis). Metal compound coatings are reduced to their respective metals by chemical or galvanic means. The current collectors described are particular suitable for use in sealed primary or rechargeable galvanic cells containing mercury-fee and lead-free alkaline zinc electrodes.
摘要:
A novel activation/etch method is disclosed for conductive polymer substrates and conductive polymer composite substrates to achieve good adhesion to subsequently applied coatings. The method in a preferred case involves anodically polarizing conductive polymers/polymer composites in aqueous etching solutions.
摘要:
Metal-clad polymer articles containing structural fine-grained and/or amorphous metallic coatings/layers optionally containing solid particulates dispersed therein, are disclosed. The fine-grained and/or amorphous metallic coatings are particularly suited for strong and lightweight articles, precision molds, sporting goods, automotive parts and components exposed to thermal cycling although the CLTE of the metallic layer and the one of the substrate is mismatched. The interface between the metallic layer and the polymer is suitably pretreated to withstand thermal cycling without failure.
摘要:
Metal-coated polymer articles containing structural substantially porosity-free, fine-grained and/or amorphous metallic coatings/layers optionally containing solid particulates dispersed therein on polymer substrates, are disclosed. The substantially porosity-free metallic coatings/layers/patches are applied to polymer or polymer composite substrates to provide, enhance or restore vacuum/pressure integrity and fluid sealing functions. Due to the excellent adhesion between the metallic coating and the polymer article satisfactory thermal cycling performance is achieved. The invention can also be employed as a repair/refurbishment technique. The fine-grained and/or amorphous metallic coatings are particularly suited for strong and lightweight articles, precision molds, sporting goods, aerospace and automotive parts and other components exposed to thermal cycling and stress created by erosion and impact damage.