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Platinum Metals Rev., 1977, 21, (2), 64

Abstracts of current literature on the platinum metals and their alloys

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PROPERTIES

The Wetting of High Temperature Oxides by Molten Platinum and Its Work of Adhesion

e. l. lubinin, s. g. gushchin, a. i. timofeev and l. v. uzberg, Izv. Vysshikh Ucheb. Zaved., Tsvetnaya Metal., 1976, 19, (5), 151–152

Studies of the wetting of BeO, MgO, Y2O3 and ZrO2+20% Y2O3 by molten Pt were carried out in He atmosphere at temperatures ranging from the melting point of Pt up to 2100°C, using the sessile drop method. It is shown that BeO is least wetted by Pt. The wetting angle θ of Pt on BeO changes from 120 to 110° at 1800−2000°C, and the work of adhesion changes from 800 to 1100 MJ/m2 in this temperature range. The wetting angles on MgO and Y2O3 were 92 and 88° respectively and were found practically constant with temperature. The value of θ on ZrO2 +20% Y2O3 decreases with increasing temperature from 85 to 60° and the work of adhesion increases from 1950 to 2400 MJ/m2.

Effect of Carbon and Water on Wetting and Reactions of B2O3-containing Glasses on Platinum

g. a. holmquist and j. a. pask, J. Am. Ceram. Soc., 1976, 59, (9–10), 384–386

The wetting characteristics of molten B2O3 and B2O3-containing glasses on Pt were studied using the sessile drop method, at 700−1000°C under ambient pressures of 10−4 torr to 1 atm. It is shown that in atmospheres free of carbonaceous gases, the contact angle for all glasses on Pt was small and independent of pressure and temperature. Adsorption of C at the metal surface increased the contact angle. Absorption of H2O vapour by the glasses resulted in a reaction at the solid/liquid interface, spreading of the glass and adherence.

Adsorption of H2 and CO on Clean and Oxidised (110) Pt

r. w. mccabe and l. d. schmidt, Surface Sci., 1976, 60, (1), 85–98

Studies of binding states and sticking coefficients of CO and H2 on clean and oxide covered (110) planes of Pt were made using flash desorption mass spectrometry and Auger electron spectroscopy. The results show that both adsorbates have higher binding energies on the oxide than on the clean surface. Initial sticking coefficients for CO were 1.0 and 0.85 and for H2 0.15 and 0.28 on clean and oxidised surfaces respectively.

Interaction of Hydrogen with Pt(111): The Role of Atomic Steps

k. christmann and g. ertl, Surface Sci., 1976, 60, (2), 365–384

The interaction of H2 with stepped Pt(S)–9(111) × (111) surface was studied using LEED, AES, ELS, thermal desorption and work function techniques. It was found that the saturation coverage with dissociatively adsorbed H2 at 120K is near unity. The presence of steps increased the initial sticking coefficient by a factor of four to a value of 0.34. The activity for H2−D2 exchange reaction was enhanced by an order of magnitude. A model in which two different types of adsorbed H atoms are associated with the atomic steps is proposed.

Ductile-Brittle Transition in Metallic Glasses

h. s. chen, Mater. Sci. Engng., 1976, 26, (1), 79–82

Studies of the ductile-brittle behaviour in (M1−xNx)0·75P0·16B0·06Al0·03 alloy with M, N = Fe, Co, Ni, Cr and Mo show that the Fe, Co, Mo and Cr metallic glasses are very brittle in comparison with the Ni, Pd and Pt based glasses. It is suggested that the incomplete d -shell orbitals of the Fe, Co, Cr and Mo atoms lead to higher resistance to shear strains and brittle behaviour. The Ni, Pd and Pt glasses by filling the d -shell of the transition metals ensure a relatively low shear modulus and ductile behaviour.

Strengths and Stiffnesses of Metallic Glasses

l. a. davis, c.–p. chou, l. e. tanner and r. ray, Scripta Metall., 1976, 10, (10), 937–940

The elastic and plastic properties of a number of metallic glasses including Pd80Si20, Pd77·5 Cu6Si16·5 and Pd40Ni40P20 were studied and a simple correlation of the strengths and stiffnesses of these glasses was observed. The correlation between the strengths and stiffnesses is given in terms of the Vickers hardness, Young’s modulus, density and the velocity of extensional mode ultrasonic waves.

The Motions of Hydrogen Impurities in α-Palladium Hydride

w. drexel, a. murani, d. tocchetti, w. kley, i. sosnowska and d. k. ross, J. Phys. Chem. Solids, 1976, 37, (12), 1135–1139

Studies of the intensity distribution of inelastically scattered thermal and hot neutron on H impurities in α-palladium hydride were made as a function of concentration, temperature, momentum transfer and different annealing procedures. The results show that at higher concentrations and with insufficient annealing treatment clusters of H atoms are formed even in the α-phase, producing a local lattice distortion.

Superconductivity in the Pd1−xMxHc (M is Noble Metal) and PdByHc Alloy Systems

a. w. szafrański, t. skośkiewicz and b. baranowski, Phys. Status Solidi A, Appl. Res., 1976, 37, (2), K163–K164

The dependence of the transition temperature T c on the H2 content in several Pd-Cu and Pd-Ag alloys and on the H + B content in several Pd-B alloys was studied. The results show that the increase of H2 concentration causes an increase of T c and that the higher the Cu, Ag or B concentration the lower is the c-value corresponding to the appearance of superconductivity. The presence of noble metal (and also B) atoms in the Pd alloy considerably reduces the solubility of H2.

Metallic Glasses

h. s. chen, Mater. Sci. Engng., 1976, 25, 59–69

A review of the physical properties of metallic glasses including Pd-Au-Si, Pd-Cu-Si, Pd-Si, Pd-Ni-P and Pt-Ni-P, is presented. The formation, stability and glass transition as well as structure, structure relaxation and crystallisation are discussed. The mechanical behaviour and magnetic properties are summarised. Acoustic and electron transport properties are described.

The β→α Phase Transformation in Palladium-Hydrogen Alloys

h. c. jamieson, g. c. weatherly and f. d. manchester, J. Less-Common Metals, 1976, 50, (1), 85–102

A room temperature study has been made of the β→α phase transformation in thin foils of annealed β-palladium hydride using electron microscopy and diffraction techniques. Initially coherent precipitation of α was observed close to the surface of the foil while the transformation proceeds in a discontinuous manner accompanied by the formation of a high dislocation density and microcracks in the α phase. It is thought that the rate of transformation is controlled by the formation of molecular H2 at the foil surface.

The Internal Friction and Elastic Modulus of Amorphous Pd-Si and Fe-P-C Alloys

t. soshiroda, m. koiwa and t. masumoto, J. Non-Cryst. Solids, 1976, 22, (1), 173–187

Internal friction of an amorphous Pd-Si alloy was measured from room temperature to ∼550°C using a specially designed micro-tension pendulum. It is shown that the internal friction of the amorphous alloy increases steeply with temperature. A wide range of distribution in activation energies was observed. The shear modulus was found to increase by ∼30% upon crystallisation.

The Influence of Adsorbed Carbon on the Condensation of Molecular NaCl on Ir and Pt

yu. a. gel’man, yu. n. lyubitov, v. i. mikhailov, v. f. vinogradov and a. a. chernov, Kristallografiya, 1976, 21, (6), 1175–1177

Studies of the nucleation and growth of NaCl crystals on Ir and Pt show that the condensation rate on clean substrates is considerably higher than that on substrates covered with adsorbed C. This is attributed to a lower energy of adsorption of the NaCl on the C covered surfaces of Pt or Ir.

Thermal Expansion Measurements Near the Antiferromagnetic Phase Transitions in K2ReCl6 and K2IrCl6

h. w. willemsen, r. l. armstrong and p. m. meincke, J. Low Temp. Phys., 1977, 26, (1/2), 299–309

The linear thermal expansion coefficient measurements for K2IrCl6 and K2ReCl6 show anomalous behaviour near the antiferrromagnetic phase transition. The results show that the contribution of the next-nearest-neighbour exchange interaction to the thermal strain is of opposite sign for the two compounds.

Studies of the Phase Composition and Electrical Transport Properties of the RuO2-TiO2 System

yu. e. roginskaya, b. sh. galyamov, v. m. lebedev, i. d. belova and yu. n. benevtsev, Zh. Neorg.Khim., 1977, 22, (2), 499–504

X-ray studies of the RuO2-TiO2 phase diagram at 900, 1200 and 1350°C show that there are two regions of limited solubility, one near the TiO2 and another near the RuO2. In the remaining concentration range there exist two rutile phases which are solid solutions of TiO2 in RuO2 and RuO2 in TiO2. The dependence of electrical conductivity and thermal e.m.f. of the Ti1−xRuxO2 (x=1−6 mole%) solid solutions on the composition, temperature and partial pressure of O2 is discussed. The defect structure in the crystal lattice of these solid solutions is presented.

CHEMICAL COMPOUNDS

An Analytical Study of Platinum Silicide Formation

j. b. bindell, j. w. colby, d. r. wonsidler, j. m. poate, d. k. conley and t. c. tisone, Thin Solid Films, 1976, 37, (3), 441–452

AES, secondary ion mass spectroscopy and electron probe microanalysis were used to study the kinetics of Pt silicide formation and the surface effects were found to relate to O2 and Al contamination of the films. The contaminants moved with the Pt-Pt silicide interface during subsequent annealing, while additional oxidation occurred at the surface due to some very small amount of O2 in the annealing ambient.

Crystal Structure of Pd16S7

p. matković, m. el-boragy and k. schubert, J. Less-Common Metals, 1976, 50, (2), 165–176

Crystallographic studies of the Pd-S system show that the phase Pd16S7 has a cubic body-centred structure with 46 atoms in the cubic cell and is related to the γ-brass structure. The phases Pd4S, Pd3S.h, Pd16S7, PdS and PdS2 were interpreted as energetically favourable in terms of the two-electron correlation model.

ELECTROCHEMISTRY

The Effect of Anions on Hydrogen Chemisorption and Oxide Formation on Pt in Aqueous Acids

p. n. ross, J. Electroanal. Chem. Interfacial Electrochem., 1977, 76, (1), 139–145

A potentiodynamic cyclic voltammetry method was used to study the component processes of H chemisorption on Pt and Pt oxide formation in H2SO4, HClO4 and HF aqueous acids. Processes of H adsorption/desorption and Pt oxide formation occurred only in H2SO4 and not in HClO4 or HF, and thus represent anion interference with the faradaic reactions. The strong H species were observed in 1M HF + 10−3M H2SO4.

Effect of the Addition of Ruthenium Trichloride on Oxygen Overvoltage at a Platinum Anode in Aqueous Acidic Solution

c. iwakura, a. asada and h. tamura, Denki Kagaku, 1976, 44, (10), 639–645

The effect of the addition of RuCl3 on O2 over-voltage was studied at a Pt anode in aqueous acidic solution using cyclic voltammetry, potential-time curves and by determination of evolved O2 gas. The RuCl3 addition noticeably decreased the overvoltage for the anodic evolution of O2 at low anodic potentials which was attributed to the presence of Ru species as active sites, incorporated in the oxide film of the Pt anode. The results at relatively high anodic potentials showed that RuCl3 additions slowed down the O2 evolution, due to simultaneous oxidation of the Ru species.

Reduction of Nitric Oxide at a Platinum Cathode in an Acidic Solution

l. j. j. janssen, m. m. j. pieterse and e. barendrecht, Electrochim. Acta, 1977, 22, (1), 27–30

Studies of the reduction of NO were carried out at a Pt electrode in 4M H2SO4 using the measurement of potential/current relations and by the determination of the current efficiencies for N2O, NH3, hydrazine and H2 formation at fixed potentials from 0 to −400mV. The results showed that in the potential range of the first wave (> −30mV) NO was reduced only to N2O. In the second wave (from −50 to −250mV), NO was reduced to hydroxylamine, NH3 and NO2.

Electrochemical Study of Palladium Powder Catalysts

t. mallát, é. polyánszky and j. petró, J. Catalysis, 1976, 44, (3), 345–351

The potentiodynamic polarisation method was used for electrochemical studies of the Pd-H system. The Pd catalyst prepared by reducing H2PdCl4 solution was used in a powder form and the amount and nature of H2 sorbed on the catalyst was studied in various electrolytes. It is shown that the shape of the potentiodynamic curves and the number of hydrogen maxima depend on the age of the catalyst and on the electrolyte. The ratio of adsorbed and dissolved H2 was affected by the catalyst preparation method.

The Anodic Dissolution of Noble Metals in Relation to Their Solid State Cohesion

a. k. vijh and g. bélanger, Corrosion Sci., 1976, 16, (11), 869–872

Studies of the rates of anodic dissolution for Rh, Pd, Ir, Pt and Au at a given value of the anodic dissolution overpotential η show that these rates in 1M H2SO4 are inversely related to the metal-metal bond energies of the noble metals.

Effect of Working Electrode Substrate on the Deposition of Iron in Molten LiF-BeF2-ThF4 (72-16-12 mole %)

d. l. manning and g. mamantov, High Temp. Sci., 1976, 8, (3), 219–224

Studies of the Fe(II) reduction at Ir, Au and pyrolytic graphite electrodes were carried out using voltammetric and chronopotentiometric methods and LiF-BeF2-ThF4 as a solvent. It is shown that the Fe2+ is reversibly reduced to a soluble form at Au and to an insoluble form at pyrolytic graphite. The Fe2+ reduction at Ir gives both soluble and insoluble products depending on the temperature. Diffusion coefficient and activation energy values are derived.

ELECTRODEPOSITION AND SURFACE COATINGS

Electrodeposited Noble Metal Coatings from the Present Day Point of View

h. grossmann, Galvanotechnik, 1977, 68, (1), 48–53

A review of the current methods of plating Pt group metals and Au for decorative purposes is presented.

Increase of the Corrosion Resistance of Electrolytic Chromium Coatings by Modification with Palladium

n. d. tomashov, g. p. chernova, and t. a. fedoseeva, Zashchita Metal., 1976, 12, (1), 3–6

Studies of the corrosion resistance and the electrochemical behaviour of electrodeposited coatings of Cr modified with 1−3% Pd were carried out. The results show that these coatings are considerably more corrosion resistant in 20% H2SO4 and 5% and 10% HCl solutions than the unmodified coatings.

HETEROGENEOUS CATALYSIS

New Hydrogenation Catalysts with Platinum Deposited on Polyamide-66. IV. Comparison of the Activities of Different Catalysts in the Hydrogenation of Styrene

j.–r. bernard, c. hoang–van and s. j. teichner, J. Chim. Phys., 1976, 73, (7–8), 799–802

Spectroscopic studies of the catalytic activity of the Pt/polyamide–66 catalyst made during the hydrogenation of styrene into ethylbenzene at 100°C showed that the activity of the catalyst did not depend on the total Pt content but was proportional to the amount of Pt at surface of the nylon. The influence of the preparation of the catalyst, of the solvent and of the nature of the Pt compound on its catalytic activity was discussed.

Catalytic Reforming of Benzine Fractions on Polymetallic Catalysts

g. n. maslyanskii, b. b. zharkov, a. p. fedorov, t. m. klimenko, r. n. shapiro and r. f. pannikova Khim. Tekhnol. Topliv Masel, 1977, (1), 16–20

The catalytic reforming of benzine was carried out over polymetallic 0.6 wt.% Pt/Al2O3 and 0.35 wt.% Pt/Al2O3 catalysts at pressures of 15–35 atm. The results show that high benzene and toluene outputs are obtained during reforming over the 0.35 wt.% Pt/Al2O3 catalyst. The lowering of the working pressure down to 14 atm led to a further increase of the hydrocarbon output.

Relative Importance of Thermal and Chemical Deactivation of Noble Metal Automotive Oxidation Catalysts

r. a. dalla betta, r. c. mccune and j. w. sprys, Ind. Engng. Chem., Prod. Res. Dev., 1976, 15, (3), 169–172

The deactivation of a series of monolithic Pt/Al2O3 and Pt+Pd/Al2O3 catalysts was studied after operation in vehicles for 50,000 miles. It is shown by transmission electron microscopy that the metal particles grew from ∼60Å to 1000Å. The CO chemisorption techniques show that the available metal area decreased to 3 × 10−4 m2/g. The thermal sintering causes loss of 95% of the original metal area and poisons deactivate 95% of the remaining metal area.

Sulphur Storage on Automotive Catalysts

k. c. taylor, Ind. Engng. Chem., Prod. Res. Dev., 1976, 15, (4), 264–268

Studies of the Pt-Pd/Al2O3 pellets catalyst activity for SO2 oxidation were made in a catalytic reactor. It was found that the catalyst composition, support characteristics and catalyst pretreatment influence the catalytic oxidation of SO2, but the main influence is due to S storage on pelleted catalysts. It is suggested that S storage may provide an effective means of lowering H2SO4 emissions.

The Kinetics of Hydrogen Peroxide Decomposition on Platinum Adsorption Catalysts

z. v. luk’yanova, t. g. martynyuk, v. i. shekhobalova and t. a. pospelova, Zh. Fiz. Khim., 1976, 50, (11), 2837–2840

Kinetic studies of H2O2 decomposition on Pt/SiO2, Pt/Al2O3 and Pt/SiO2-Al2O3 adsorption catalysts and on Pt black show that the reaction order is ∼0.6 and it does not depend on the nature of the carrier. Deactivation of the catalysts during decomposition changes the order as well as the rate constant of the reaction. The apparent activation energy was determined to be 9−11 kcal/mole for all the catalysts.

Platinum-Rhenium-Alumina Catalysts. III. Catalytic Properties

c. betizeau, g. leclercq, r. maurel, c. bolivar, h. charcosset, r. frety and l. tournayan, J. Catalysis, 1976, 45, (2), 179–188

Studies of the activity of Pt-Re/α-Al2O3 and Pt-Re/γ-Al2O3 catalysts in five different reactions showed that the activity is not the sum of the activities of Pt and Re. The activity vs. composition curves have one or two maxima in benzene hydrogenation, benzene-deuterium exchange, cyclopentane and butane hydrogenolysis. The rate of 1,1,3-trimethyl cyclohexane dehydrogenation was found to decrease with increase of Re.

A Study of the Chemisorption of Nitric Oxide on PdY Zeolite. Evidence for a Room Temperature Oxidative Dissolution of Pd Crystallites

m. che, j. f. dutel, p. gallezot and m. primet, J. Phys. Chem., 1976, 80, (21), 2371–2381

Studies of NO adsorption on a PdY zeolite in oxidised and reduced forms were carried out using i.r. and E.P.R. spectroscopies. It is shown that NO can be reduced in N2O and the Pd can be reoxidised to such an extent that all the metal atoms are redispersed as cations on the support. These results are of practical interest for the elimination of NO in automobile exhaust and are important in the problem of catalysts ageing.

On the Catalytic Reduction of Nitric Oxide in the Presence of Oxygen

r. sigg and e. wicke, Z. Phys. Chem., Neue Folge, 1976, 103, (1–4), 181–192

Studies of the reduction of NO by H2 and CO over a number of Pd, Ag and Fe mixed catalysts supported on γ-Al2O3 showed that the three-component catalyst Pd/Ag/Fe had a remarkable selectivity for the NO reduction by H2 and CO even at O2 concentrations of 2% at the inlet. The relatively low excess temperatures of the Pd/Ag/Fe catalyst indicated a reduced selectivity of the CO oxidation by O2 as compared to the other catalysts.

Study of Adsorption Properties of a Pd/Al2O3 Catalyst

v. a. haidin, g. d. zakumbaeva and d. v. sokol’skii, Zh. Fiz. Khim., 1977, 51, (1), 183–187

Studies of the H2 sorption and specific adsorption of Zn and Cd cations on 0.05g Pd/Al2O3 catalyst were carried out using 1N H2SO4, H2O and NH4OH solvents. It is shown that the quantity of adsorbed cations depends on their concentration in the solution and on the nature of the solvent. The effect of temperature on the amounts of sorbed H2 and adsorbed cations is discussed.

Organic Hydrogen Getters

r. l. courtney and l. a. harrah, J. Mater. Sci., 1977, 12, (1), 175–186

A 5% Pd-CaCO3 catalyst in combination with an unsaturated dimerised phenyl propargyl ether-DPPE was developed for gettering H2 irreversibly from closed systems via a chemical reaction. The activation energy for H2 uptake was found to be 9.4 kcal/mole at 22−55°C. The getter material can be used as a powder or be packaged in a bag through which H2 can permeate. The getter is shown to be non-explosive and non-pyrophoric.

Electrochemical Study of Palladium-Copper Catalysts

t. mallát, j. petró, é. polyánszky and t. máthé, Acta. Chim. Acad. Sci. Hung., 1976, 90, (4), 333–344

The correlations between the H2 sorption and catalytic activity of Pd-Cu powder catalysts with 0, 10, 20, 30, or 40 at.% Cu were studied using galvanostatic and potentiodynamic methods in 1N NaOH and 1N H2SO4 respectively. The catalysts activities were measured in liquidphase hydrogenation at 25°C and 1 atm. The quantitative decrease of the dissolved H2 was observed on 0−20 at.% Cu-Pd catalysts while for 20−40 at.% Cu-Pd catalysts, the decrease was primarily in the adsorbed H2.

The Effect of Thermal Treatment on the Catalytic Activity of Skeleton Iridium in the Acetone Reduction

o. g. novozhilova, a. i. pletyushkina, a. d. semenova and g. d. vovchenko, Vest. Moskov. Univ. Ser. II, Khim., 1976, 17, (5), 615–617

Studies of the catalytic activity of a skeleton Ir electrode catalyst in the acetone reduction show that thermal treatment of the catalyst in a H2 atmosphere at 100−600°C has no significant effect on the adsorption and hydrogenation of acetone.

The Catalytic Activity of Rh, Ru and Ir Blacks, Deposited on Pt Supports, in the Processes of Reduction and Electroreduction of Maleic Acid

d. g. naryshkin and i. v. kudryashov, Zh. Fiz. Khim., 1976, 50, (9), 2315–2319

The catalytic activities of Pt supported Rh, Ru and Ir black electrodes were studied in the electroreduction and hydrogenation of maleic acid. The results show that the catalytic activity changes in the following order Rh> Ir> Ru.

The Kinetics and Mechanism of Carbon Monoxide Hydrogenation over Silica-Supported Ruthenium-Copper Catalysts

g. c. bond and b. d. turnham, J. Catalysis, 1976, 45, (2), 128–136

Studies of the activity of Ru-Cu/SiO2 catalysts for CO hydrogenation at 530−670K show that the activity decreases with increasing Cu content, while the activation energy remains constant at 21 kcal/mole. The catalyst containing 1% Ru and 0.32% Cu initially produces less ethane and propane than does the pure Ru catalyst.

Ruthenium Zeolite Hydrogenation Catalysts

b. coughlan, s. narayanan, w. a. mccann and w. m. carroll, Chem. and Ind., 1977, (3), 125–127

The catalytic activities of Ru L, A, X, Y and mordenite zeolites, catalysts with widely different cation densities, cation binding energies, pore structure and molecular sieve properties were studied in the hydrogenation of benzene. The results show that a Ru-L zeolite in which the Ru metal is highly dispersed is an excellent hydrogenation catalyst. Good activities were also observed for Ru zeolites X, Y and mordenite in which the metal is not so well dispersed.

HOMOGENEOUS CATALYSIS

The Isotopic Exchange of Benzofurans with Heavy Water in the Presence of Potassium Tetrachloroplatinate

e. a. karakhanov, a. g. delov, l. v. popov and e. a. viktorova, Vest. Moskov. Univ. Ser. II, Khim., 1976, 17, (5), 595–597

Studies of H-D exchange between heavy water and benzofurans were carried out at 120°C in the presence of homogeneous K2PtCl4 as a catalyst. The difference in reactivity of benzofuran and its alkyl derivatives was discussed in terms of a homogeneous dissociative π-complex mechanism.

Transition Metal Catalysed Rearrangements of Small Ring Organic Molecules

k. c. bishop, Chem. Rev., 1976, 76, (4), 461–486

The literature on the molecular rearrangements, catalysed by transition metals, in organic molecules with three- and four-membered rings is critically surveyed. (132 Refs.)

CHEMICAL TECHNOLOGY

Enhanced Low Temperature Sintering of Tungsten

r. m. german and z. a. munir, Metal. Trans., 1976, 7A, (12), 1873–1877

The influence of Pd, Pt, Fe, Co, Ni and Cu additions on the sintering of a fine W powder was studied using the isothermal and constant heating rate experiments at 900−1400°C. The results show that Pd is the best activator for the densification of W, followed by Ni, Co, Pt and Fe. A considerable acceleration of the sintering process is obtained when four atomic monolayers of Pd are present on the W powder surface. Near-theoretical densities are achieved at temperatures as low as 1200°C.

ELECTRICAL AND ELECTRONIC ENGINEERING

Differences between Platinum- and Gold-doped Silicon Power Devices

m. d. miller, I.E.E.E. Trans. Electron Devices, 1976, ED-23, (12), 1279–1283

The effects of Au and Pt diffusions on the properties of Pt- and Au-doped p+-n junctions were studied. It was found that there are substantial differences between the energy levels introduced by these impurities. Pt shows improved high-temperature properties and turn-on performance and is better for devices which are switched on rapidly.

Materials Selection in Hybrid Product Design

r. d. gold, Solid State Technol., 1977, 20, (1), 31–35 and 57

The Pd-Ag conductor paste was found to be economical and reliable as a solderable conductor when used with a Sn-free Pb-Ag-In solder, in the manufacture of power hybrid voltage regulators.

MEDICAL USES

Anti-tumour Agents Synthesised from K2PtCl4 and Polymeric or Cyclic Phosphazenes

h. r. allcock, r. w. allen and j. p. o’brien, J. Chem. Soc., Chem. Commun., 1976, (18), 717–718

Complexes between a square-planar Pt unit, K2PtCl4, and polymers such as the phosphazenes [NP(NHMe)2]4, [NP(NHMe)2]4 or [NPMe2]4 were obtained. These complexes of the type [H2N4P4R8]2+[PtCl4]2− show significant antitumour behaviour in preliminary testing.

An Explanation for the Efficacy of Attack by Platinum Blue Drugs on Biopolymers

c. c. f. blake, s. j. oatley and r. j. p. williams, J. Chem. Soc., Chem. Commun., 1976, (24), 1043–1044

Platinum halides and amides can react to form platinum blues, useful anti-tumour agents which are used as stains for biological specimens. Studies made of the interaction of these polymeric compounds with protein crystals have suggested a possible mode of action.

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