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Journal Archive

Platinum Metals Rev., 1977, 21, (3), 105

NEW PATENTS: July 1977



Electroconductive, Corrosion Resistant Silicon Alloys

p.p.g. industries inc. British Patent 1,466,455

A Si alloy has an electroconductivity greater than 100/Ωcm and consists of 0.2−2% of a dopant selected from N, P, B and Al, 1−<50% of a transition metal such as Ru, Rh, Os, Ir, Pt, Pd, Ag or Au, balance Si. The alloy has a structure in the form of a predominant, discontinuous, Si rich phase, continuous rivulets of a transition metal silicide rich phase surrounding the Si rich phase, and discrete nodules of a phase rich in the dopant material.

Re-orientation of Grain Stabilised Platinum

johnson matthey & co. ltd. U.S. Patent 4,002,503

The mechanical properties of a previously hardened Pt-Rh alloy which includes dispersed phase Zr oxide as a strengthening element are improved by cold working the composition at a temperature below that at which recrystallisation occurs and then annealing. The recrystallisation which occurs during annealing results in an elongated grain structure highly oriented in the direction of working.

High Temperature-stable Metal Powder

johnson matthey & co. ltd. German Offen. 2,630, 062

A metal powder which does not agglomerate or sinter at or around the melting point of the metal consists of a refractory substrate such as Al2O3, SiO2 or Si carbide coated with a Pt group metal, Au or Ag.


Osmium Tetroxide Complexes

johnson matthey & co. ltd. German Offen. 2,630,823

Complexes may be formed from OsO4 and compounds with a heterocyclic ring having one or two N atoms, such as phthalazine, and used for the fixing and/or dyeing of cells. The treated cells may then be examined by electron microscopy.


Bipolar Cell

solvay et cie. s.a. British Patent 1,469,832

A bipolar diaphragm-type multicompartment cell consisting of a stack of bipolar elements has the anode structure of the elements of the cell formed of Ti with a coating including one or more Pt group metals or oxides.

Platinum-Iridium Catalytic Anode

general electric co. U.S. Patent 3,992,271

A catalytic anode, for use in a gas generation apparatus, used for concentrating O2 or generating O2 and H2 by electrolysis, employs a Pt-Ir alloy, with an Ir content of 5−50%, as a catalyst.

Noble Metal Electrodes for a Combustible Sensor

westinghouse electric corp. U.S. Patent 4,005,001

An apparatus for determining the presence of predetermined combustible constituents such as methane, H2 and CO, in an excess O2 gas mixture is a solid electrolyte electrochemical cell which has one electrode made from Pt, Pd or Rh and the other from Ag or Au.


Particle Detection

w. l. fite et al British Patent 1,465,751

A particle of dust or a macromolecule of 1000 AMU or greater is induced to strike a heated surface of Pt, Ir, Re or Rh, to cause the release of electrons or ions as a detached burst, and a detector is located so as to sense the electrical charge of the burst. This induces in the detector an electrical pulse, the magnitude of which is related to the particle size.

Ceramic Gas Sensor

ford motor co. ltd. British Patent 1,467,735

The partial pressure of O2 in an ICE exhaust gas, is sensed by a device which has a porous, sintered ceramic body of particles of a 99.5% pure transition metal oxide, a pair of Pt electrodes and electrical means connected to the electrodes for responding to the inter-electrode resistance. They include a Pt-Rh alloy resistance wire and a Au-Pd-Pt and Au-Pd combination thermocouple.

Ignition Device

johnson matthey & co. ltd. German Offen. 2,630,749

An ignition device generates sparks between two electrodes projecting from or mounted on insulating or semiconducting surfaces. The active surfaces consist predominantly of Co or Ni alloyed or composited with one or more metals from the group consisting of Ru, Rh, Pd, Ir, Pt, Au or Ag.


Brazing Alloys Containing Noble Metals

v. p. kosteruk et al U.S. Patent 3,998,632

A brazing spelter composition for joining high melting carbides, ceramics, etc., to each other or to high melting alloys consists of 2−30% Cu, Au and/or Ag, 2−21% Al, B, Sc, Y, lanthanides, C, Si, Ge, Ti, Zr, V, Nb, Ta, P, Cr, Mo, W, Mn, Tc, Re, Os, Co, Ni, Rh, Ir and/or Pt, and the balance Hf.


Amorphous Platinum Metal Particles

british petroleum co. ltd. British Patent 1,470,034

A new form of Pt consists of amorphous Pt metal particles which do not produce the X-ray diffraction pattern characteristic of crystalline Pt. The particles are produced by depositing Pt on a support, oxidising it at a temperature of at least 300°C and then reducing it at a similar temperature in H2.

Hydrazine Decomposition Catalyst

kali-chemie a.g. British Patent 1,470,260

A catalyst for the spontaneous decomposition of hydrazine and its derivatives, especially for space propulsion systems, is obtained by impregnating active Al2O3 with an Ir compound and optionally an Os compound at least four times. After each impregnation the damp product is dried at 100−300°C in an inert atmosphere before finally the compound is reduced to metal at a temperature of 180−300°C in H2.

Helium Cooled Nuclear Reactors

u.k. atomic energy authority British Patent 1,470,795

The reactor has further (recycling) circuitry in addition to a closed loop main coolant circuit, which includes a Pt catalyst for oxidising the H2 content of the coolant gas.

Storage Battery Catalysts

robert bosch g.m.b.h. British Patent 1,471,307

A recombination catalyst for gases generated in a secondary cell consists of bodies of Pd or C, or the like, sheathed in PTFE so that they are able to float in the battery electrolyte.

Platinum Metal Conversion Catalysts

exxon research & engineering co. U.S. Patent 3,993,598

The preparation of two novel catalysts for the catalytic hydro-conversion of hydrocarbon material contained in heavy crudes and residuals is described. The method consists of dispersing a compound of a Group VIB and/or Group VIII, such as Pt, Pd, Ir, Os, Ru, Rh, etc., and an Al halide salt in an aqueous or alcoholic medium, maintaining the temperature at 30−100°F, adding olefin oxide and maintaining the pH at 5–8, raising the temperature so as to form a cogel, ageing the cogel, separating, washing, drying and calcining the cogel and impregnating the resulting catalyst with a Group IVA metal oxide.

Catalyst Support Assembly

matthey bishop inc. U.S. Patent 3,993,600

A catalyst support structure, for use with woven gauzes of Pt metal or Pt/Rh alloy, in catalytic convertors, consists of a number of woven screens stacked together, the screens being composed of an alloy of 4−6% Al, 20−30% Ni, 0.25−1.0% Cr and the balance Fe.

Platinum Group Exhaust Gas Purification

e. i. du pont de nemours & co. U.S. Patent 4,001,143

The catalyst is prepared by impregnating Al2O3 with a solution which contains at least one Pt group metal which will be present in a concentration of 0.001−5.0% on the support, at least one lanthanide in an atomic amount of 1–1000 times that of the Pt group metal and at least one Group IA or IIA metal compound in an atomic amount of 0.25–4 times that of the Pt group metal, drying and heating at least 800°C for 1 h.

Platinum Group Catalyst for a Battery

japan storage battery co. ltd. U.S. Patent 4,002,496

A catalyst produced by impregnating a Pt group metal, such as Pd, into granules obtained by sintering and forming active Al2O3, is used in a battery which contains an aqueous electrolyte.

Noble Metal Catalyst for Cleaning Air Which Contains Carbon Monoxide

kanebo ltd. U.S. Patent 4,003,979

Polluted air containing CO is cleaned by passing it through an adsorbent filter and through a noble metal catalyst layer. The catalyst preferably consists of Pd on active C with 20−50% H2O.

Purification of Exhaust Gases

institut francais du petrole French Appl. 2,298,688

The exhaust gas, together with air, is passed over a catalyst bed, the air being introduced in variable quantities during the passage of the gas over the catalyst bed. The amount of air introduced depends on the quantity of the exhaust gas produced by the engine. The catalyst consists of the oxide(s) of Pt, Rh, Cu, Ag, Zn, V, Cr, Mo, W and Mn on a refractory support.


Colloidal Platinum Catalyst

prototech co. U.S. Patent 3,992,331

An improved catalyst, for various uses, especially under high temperature conditions, is prepared by applying a compound of formula H3Pt(SO3)2 OH to a substrate, thermally decomposing the acid in air and then reducing it to form metallic Pt particles having an average particle size in the range 15−25Å.

Ruthenium, Iridium and Rhodium Hydrogenation Catalyst

firestone tyre & rubber co. U.S. Patent 3,993,855

Selective hydrogenation of unsaturated hydrocarbon polymers is catalysed by the complexes RhCl(PPh3)3, RhClCO(PPh3)2, RhHCO(PPh3)3, RuHCl(PPh3)3 and IrH3(PPh3)3.

Asymmetric Hydrogenation Catalyst

monsanto co. Dutch Appls. 76.09339–40

Asymmetric hydrogenation, especially of acetamidophenyl propane enantiomorphs, is catalysed by a Rh, Ru or Ir optically active bisphosphine complex, such as a Rh fluoroborate complex of a di(anisylphenylphosphino)ethane.

Hydroformylation Catalyst

johnson matthey & co. ltd. Russian Patent 503,503

The hydroformylation of olefins e.g., propylene to alcohols and aldehydes is catalysed by a neutral Rh complex, specifically hydrocarbonyl tris-(triphenylphosphine)Rh, RhH(CO)(PPh3)3, in the presence of an excess of triphenylphosphine.


Flow-Through Type Fuel Cells

kanebo ltd. British Patent 1,467,147

The cell consists of a cathode, an anode and an electrochemical separator. At least one of the electrodes consists of a layer of a woven or knitted fabric formed from organic high polymer fibres of 1–30 μ m diameter, each fibre having a 0.1–10 μ m thick metal layer on its surface and an electrocatalyst on the metal layer. The metal is Ti, Cr, Rh, Pd, Ru, Pt, Ag, Au etc., and the electrocatalyst is Pt, Pd, Rh, Ir, Ni, Cu and Ag.


Recovery of Small Particles of Precious Metals

e. o. anders U.S. Patent 3,998,629

Small particles of Pt or Au are recovered from a slurry by feeding the slurry on to a layer of Hg which is flowing down along a conical, downwardly converging inner wall of a housing. The housing is rotated about the vertical axis of the wall at a speed which reduces particles to settle out or amalgamate with the Hg. The particles are subsequently separated out and recovered.

Regeneration of Platinum Group Hydrogenation Catalysts

e. i. du pont de nemours & co. U.S. Patent 3,998,936

A Pt group hydrogenation catalyst, used in the manufacture of peroxide from an alkylanthraquinone, is regenerated by contacting it, in the presence of the working solution and in the absence of H2, with either an O2 containing gas or H2O2.

Palladium Additive for Metallisation Activation Bath

langbein-pfanhauser werke a.g. U.S. Patent 4,001,470

An activation bath for use in the chemical coating of synthetic resin bodies with Ni or Cu contains 0.1–20 g gelatin or gum arabic, 1–5 g tartaric or citric acid, 1–5 g H2SO4 or HCl, 0.1–5.0 g Pd sulphate, 1–20 g maleic or 1–6 g fumaric acid and H2O to a volume of 1 l.

Palladium Treatment of Electroconductive Non-Woven Fabrics

hoechst a.g. U.S. Patent 4,002,779

The fabrics are manufactured by cleaning a non-woven polar fabric with a polar organic solvent, sensitising the fibre surfaces of the fabric with an aqueous HCl solution of stannous chloride, rinsing with H2O, activating the surface of the fibres with an aqueous HCl solution of PdCl2.

Pressed Metal Powder Coins

metallwerk plansec a.g. German Offen. 2,633,323

The counterfeiting of coins is made more difficult by pressing coins from a powder mixture which is not homogeneous and/or which contains “tracers” such as Mo, Ta or Th oxide. Pt alloys can be used to produce homogeneous coins containing such a tracer.


Glass Fibre Spinneret Mounting

pilkington brothers ltd. British Patent 1,471,306

Glass is supplied from a forehearth through a duct and an apertured cover plate before reaching a bushing. This arrangement keeps the duct hot and reduces spun fibre breakage. The cover plate and duct are preferably made of the same material as the bushing, a Pt-Rh alloy.


Manufacturing Microwave Devices

general electric co. ltd. British Patent 1,464,511

A microwave device has a component of ferrite material in which are embedded Pt group metal conductors produced by laying the conductors in grooves in the ferrite body and plasmaspraying ferrite onto the conductors.

Compression Bond Assembly for a Planar Semiconductor Device

westinghouse electric corp. British Patent 1,465,328

Thermal and electrical contact is obtained between a first mounting electrode contact and a first semiconductor region using a planar electrically and thermally conductive preform of Pt and/or Ir or their alloys.

Schottky Barrier Field Effect Transistor

u.s. secretary of the air force U.S. Patent 3,999,281

In the manufacture of the transistor Pt is deposited only at the bottom of the groove of a single high resolution mask. This obviates the need for an additional photo-masking step or the necessity of subsequent removal of Pt from other surfaces of the wafer.

Silver Electrical Conductor Compositions

e. i. du pont de nemours & co. U.S. Patent 4,001,146

Compositions for making electrical conductor patterns on a non-conductive substrate consist of a metal powder and 1−5% glass-free inorganic binder. The binder is made up of Bi oxide and Cu and/or Pb oxides, and optionally MnB2 and/or MnO2. The metal powder is either Ag or a mixture of Ag with Pt, Pd, Au or an alloy of Cu with one or more of Pt, Pd, Au and Ag.


Paint-On Thermocouple

u.s. secretary of the navy U.S. Patent 4,004,948

A paint-on thermocouple is made of thin films of a finely divided mixture of Pt, Ag and Au and the alloy constant is painted on to the surface to be tested.

Resistance for a Resistance Thermometer

w. c. heraeus g.m.b.h. German Offen. 2,527,739

A resistance for temperature measuring purposes consists of 0.1–10 μ m of Pt deposited on an oxidic support, such as Al2O3.