Journal Archive

Platinum Metals Rev., 1973, 17, (4), 155

NEW PATENTS: October 1973


Hydrogen Diffusion Membranes

n. r. d. c. U.S. Patent 3,713,270

H2 is separated from gas mixtures using membranes made from an alloy of Pd with lanthanides, (not La or Pr), e.g. 8·5%Y–Pd or 10%Ce–Pd.

Spinneret Alloy

comptoir lyon-alemand louyot&cie. French Patent 2,133,178

Spinnerets for synthetic fibre production are made from an alloy of 80.5−90% Au, 10−19.5% Pt and 0−3% of at least one of Rh, Ir, Ru, Os and Re.

Platinum Group Metal Cladding

johnson matthey&co. ltd French Patent 2,142,425

A core of refractory metal is surrounded by an intermediate layer of MgO on which is deposited a Pt group metal.


Organometallic Complexes

studiengesellschaft kohle m.b.h. British Patent 1,315,473

Pt group metal complexes may be produced electrolytically by using a cathode of the requisite metal and an electrolyte containing the complexing agent.


Electrochemical Cells

philip morris inc. British Patent 1,318,713

Electrochemical cells using a fluoride electrolyte have Au or Pt metal cathodes.

Hydrogen Absorption in Electrochemical Cells

union carbide corp. British Patent 1,321,853

Pd is used with MnO2 in a binder to form a device absorbing and oxidising H2.

Electrolysis Electrodes

p.p.g. industries inc. British Patent 1,323,756

Electrolysis electrodes have a Ti or similar metal base plated with a Pt group metal from an organic bath containing a highly ionisable electrolyte. A typical bath contains 0.78g H2PtCl6, 75ml absolute EtOH, 15 ml H2SO4, 20 ml toluene and 20 ml acetone.

Electrolysis Electrode

p.p.g. industries inc. U.S. Patent 3,718,551

The electrolysis of brines is effected with a Ti base electrode coated with a mixture of amorphous TiO2 and Ru or RuO2.

Electrochemical Electrodes

solvay&cie. French Appl. 2,140,074

Electrochemical electrodes are made from a body of Ti or Ti alloy coated with a layer of heat-decomposable compounds of Ir and at least one of Li, B, Be, Mg, Ga and Ge in a liquid vehicle.


Osmium Electrodeposition

international nickel ltd. British Patent 1,322,175

Os is electroplated at a temperature of at least 50°C from a hexachlorosmate bath (preferably (NH4)2OsCl6) containing sulphamic or sulphuric acid to give a pH of 0–4.

Silver-Palladium Plating

allis-chalmers mfg co. U.S. Patent 3,725,219

An article is provided with an Ag strike, plated with Ag from a cyanide bath, plated with Pd from a chloride bath and then the Ag and Pd fused together.


Gas Analysis

esso research&engineering co. British Patent 1,320,954

A gas stream containing a low concentration of hydrocarbons is analysed by passing it over a heated noble metal or noble metal alloy wire whose heating voltage is sequentially varied. A Pt or Pd wire is preferred.

Oxygen Control Cell

babcock&wilcox co. German Offen. 2,242,851

The O2 contents of gases are metered by a cell having porous Pt electrode strips. These may be soldered using Au to thermoelements.


Hydrocarbon Conversion Catalyst

universal oil products co. British Patent 1,323,913

An exceptionally active and resistant catalyst for hydrocarbon conversion contains Pt, Sn and Ge on a support. In one example 0.2% Ge, 0.375% Sn and 0.375% Pt are used on an Al2O3 carrier.

Motor Fuel Production

sun oil co. of pennsylvania U.S. Patent 3,719,586

Light naphtha is reformed, mixed with heavy naphtha and then hydrocracked over a Pd-zeolite catalyst to yield a motor fuel.

Exhaust Gas Catalysts

esso research&engineering co. U.S. Patent 3,719,739

Nitrogen oxides are removed from engine exhaust gases over catalysts consisting of 10−60% Ir and 40−90% Ru, as metals and/or oxides, on a conductive support such as stainless steel or chromium steel.

Conversion Catalyst

f.c. wilhelm U.S. Patent 3,725,304

A Pt-Sn catalyst for hydrocarbon conversion is obtained by impregnating Al2O3 or another support with a trichlorostannate chloroplatinate anionic complex and calcining.

Phthalic Acid Purification

standard oil co. U.S. Patent 3,726,915

The alloying of Cu with Pd on C in a Cu:Pd ratio of less than 0.5:1 enhances the activity of the Pd when used for reduction purposes, especially the selective reduction of formyl benzoic acid in crude phthalic acid.

Hydroforming Catalyst

cie. franÇaise de raffinage French Patent 2,130,881

A new hydrorefining catalyst contains 0.02−2% Pt, 0.02−2% Ir and 0.02−2% Sn on a support.

Ruthenium Impregnation

johnson matthey&co. ltd. French Appl. 2,140,599

A graphite or carbon article is purged with a gaseous fluid and is then impregnated using a solution or suspension of an Ru compound or metallic Ru in a solvent which is then evaporated.

Oxidation–Reduction Catalyst

johnson matthey&co. ltd. German Offen. 2,231,296

A core of inert material such as a ceramic is coated with an intermediate layer containing a rare-earth oxide, and then with a mixture of alloy of Pt, Rh and optionally a base metal. The Rh represents 1−50% and the base metal, if present, 0.01−25% of the total metal. The catalyst can be used for hydrocarbon oxidation and nitrogen oxide reduction reactions.

NOx Removal Catalyst

ford-werke a.g. German Offen. 2,241,582

Nitrogen oxides are removed from I.C.E. exhaust gases over a Pt and/or Pd catalyst which also oxidises CO and unburnt hydrocarbons.

Catalyst for Nitric Acid Production

deutsche gold&silber-scheideanstalt German Offen. 2,145,842

HNO3 is produced from NH3 by oxidation over a fine gauze consisting of 40−75% Pd, 1−8% Rh and/or Ru, remainder Pt.

Catalyst Support

johnson matthey&co. ltd. German Offen. 2,248,811

A support suitable for a Pt catalyst consists of a layer of heat resistant cord made from compressed tube or gauze, which has a substantially uniform thickness and at least one flat surface, attached to a gauze plate.

NOx Removal

ford-werke a.g. German Offen. 2,251,615

Nitrogen oxides are reduced in a first catalyst zone and then the products are passed over an Ru catalyst to remove any NH3 present.

NOx Removal Catalyst

johnson matthey&co. ltd. German Offen. 2,253,070

Nitrogen oxides are removed from exhaust gases over a catalytic mixture of 5−75% Ru, 0−30% base metal and remainder (not less than 5%) Pt on a suitable support. Examples of base metals which may be present are Co, Ni, V, Fe, Cr and Re. This is equivalent to Dutch Appl. 72.14540.

Oxidation–Reduction Catalyst

johnson matthey&co. ltd. German Offen. 2,256,195

An oxidation-reduction catalyst consists of an alloy or mixture of 5−55% Ru, 1−20% Rh, 0−20% base metal and remainder Pt. This is equivalent to Dutch Appl. 72.15560.

Oxidation–Reduction Catalyst

johnson matthey&co. ltd. German Offen. 2,257,228

An oxidation-reduction catalyst, e.g. for treating I.C.E. exhaust gases, consists of an inert carrier such as zircon-mullite carrying a mixture of Pt and Rh, the Rh representing up to 20% of the total metal. This is equivalent to Dutch Appl. 72.15719.

Catalytic Exhaust Gas Treatment

kali-chemie a.g. German Offen. 2,158,877

Exhaust gas is mixed with air and treated in a first oxidising bed with a mixture of Rh and Ir or Pd on a support.


Ethylene Dicarboxylic Acid

denki kagaku kogyo k.k. British Patent 1,323,619

Acetylene and CO are reacted to give ethylene dicarboxylic acid in the presence of a Pd salt of a strong acid, an amino acid and a solvent.

Polynuclear Aromatic Compounds

gulf research&development co. U.S. Patent 3,728,409

Polyphenyls and related compounds are produced by condensation in the presence of a Pt group metal salt and a strong acid. For example C6H6, PdOAc and H2SO4 in the presence of O2 give a mixture of biphenyl and terphenyl.


Nucleating Medium

hughes aircraft co. British Patent 1,314,238

Pd p -toluene sulphonate is a suitable nucleation-inducing compound in a nucleating medium for photographic purposes.

Flame Retardants for Elastomers

general electric co. U.S. Patent 3,711,520

The fire resistance of a silicone elastomer stock is improved by adding Pt or Pt compounds and a Group II metal oxide. In an example the Pt source added is a reaction product of chloroplatinic acid and a tetravinyl tetramethyl cyclotetrasiloxane.

Photoreducible Palladium Compounds

eastman kodak co. U.S. Patent 3,719,490

Physical development of Ag latent images is catalysed by light sensitive Pd compounds able to generate metal nuclei. These compounds have the formula (PdLx)yAz. Where L is a halogen, carboxylic acid, aryl, N, As, Sb or P ligand, A is H, anion or metal cation, x is 0–4, y is 1–4 and z is 0–2, e.g. potassium palladium oxalate.

Rhodium in Silver Halide Emulsions

eastman kodak co. U.S. Patent 3,720,516

Ag halide grains are precipitated in the presence of a Rh salt and a Mn stabiliser.


Platinum in Optical Glass Filters

v.e.b. jenaer glaswerk schott&gen. British Patent 1,317,395

About 0.0001–0.01 at.% Pt is added to glass for optical filters to provide centres for crystallites.

Platinum-based Alloys

johnson matthey&co. ltd British Patent 1,318,201

Alloys suitable for making articles which come into contact with molten glass, especially spinnerets, contain 15−25% Rh, 1−4% Au and the balance Pt. A diagram specifies the range.


Electrolytic Capacitor

plessey co. ltd. British Patent 1,317,494

A capacitor has a cathode of inert material coated on the face wetted by the electrolyte with a Pt group metal paint. A ceramic paint containing Pt and Ir or Au and Pd is suggested.

Thick Film Resistors

r.c.a. corp. British Patent 1,320,625

The resistivity of screen printed resistors produced using Ag-Pd is adjusted by allowing a certain dwell time at room temperature between printing and firing.

Intermetallic Contact

r.c.a. corp. British Patent 1,321,034

An intermetallic contact is produced in an opening on a semiconductor by applying a metal such as Pt, Pd or Rh which is able to alloy with the semiconductor.

Semiconductor Devices

western electric co. inc. British Patent 1,323,828

Avalanche breakdown is avoided by using a Pt Schottky barrier with extensive overhang.

Semiconductor Interconnections

r.c.a. corp. U.S. Patent 3,714,521

W semiconductor interconnections are coated with Pt where leads are to be attached.

Cathode Construction

general electric co. U.S. Patent 3,717,503

The electron emission of a cathode is increased selectively by placing a control grid above the cathode and evaporating Os or Ir through the openings on to the cathode.

Magnetic Recording Medium

fuji photo film co. ltd. U.S. Patent 3,717,504

A magnetic recording medium has a magnetisable surface layer coated with thin Ni and Rh layers.

Palladium Circuits in Alumina

american lava corp. U.S. Patent 3,723,176

A green sheet is produced from prefired Al2O3. This is screen printed with a circuit using a Pd ink. The circuit is covered with more Al2O3 and contacts provided. The second layer of Al2O3 is also screen printed with a Pd ink and the whole unit fired.

Platinised Fuse

westinghouse electric corp. U.S. Patent 3,727,091

An electric lamp containing halogen has a Pt-coated Ni or nichrome fuse wire.

Integrated Circuits

interelectric a.g. German Offen. 2,135,488

Pt group metal plating is used to reinforce thinner regions of integrated circuits.


Resistance Thermometer Element

johnson matthey&co. ltd. German Offen. 2,256,203

A temperature-sensitive element is made from a layer of glass containing conducting particles attached to a non-conducting support. Au, Ag, Pt metals, Fe, Ni, Co and Cu may form the particles. This is equivalent to Dutch Appl. 72.15561.

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