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Pressure, green density and strength of thermal battery parts
Electrical and magnetic materials
PROCESSING AND EVALUATION OF COMPOSITE MANGANESE DIOXIDE AND CARBON BASED MATERIALS
PRESSURE, GREEN DENSITY AND STRENGTH OF THERMAL BATTERY PARTS
K.Terashita et al. (Osaka Prefecture University, Sakai, Japan.) J. Jpn Sot. Powder Powder Metal., Vol 45, No 9, 1998, 872-876 and 877-881. (In Japanese.) Studies of processing and properties of MnO,-C composite materials are described. The material is used as anodes in disc shaped Li batteries. A range of process operations were investigated with the object of standardizing the final product to give reliable battery performance.
G.Portal et al. (ASB Aerospatiale Batteries, Bourges, France.) Powder Metall., Vol42, No 1, 1999,34-40. Compressibilities of powders used in making thermal batteries, FeS, cathodes, solid LiCl-KC1 eutectic electrolyte and Li anodes were investigated. Densification was explained using Kawakita and Halldin models. Mechanical properties of were considered. Green compacts strength, which is shown to be sensitive to inter-particle contact area, increased linearly with pressure. EFFFECTS OF BINDER AND DEBINDING PARAMETERS ON RESIDUAL C IN NEODYMIUM-IRON-BORON
T.J.Moon et al. (Korea University, Seoul, Korea.) Powder Metall., Vol 42, No 1? 1999,41-44. Thermal debinding of injection moulded Nd-(Fe,Co)-B compacts was investigated for a range of binders and conditions. Residual C debinding depended on binder type, debinding technique and the molecular weight of the binder. H was the most appropriate atmosphere. Low residual C was favoured by slow heating and high debinding temperature. ANALYSIS OF PARTICLE ALIGNMENT DURING COMPACTION
H.Kodera et al. (Kyoto University, Kyoto, Japan.) J. Jpn Sot. Powder Powder Metal., Vol 45, No 9, 1998, 859-865. (In Japanese.) The behaviour of magnetic powder was modelled during compaction using Magneto-Cosserat-Continuum theory and FEMs to simulate alignment of particles. Relationships between magnetic field direction and different compaction conditions are analysed. The results are compared with those from particle dynamics simulations.
TEMPERATURE DEPENDENCE OF THERMO-ELECTRIC PROPERTIES OF Sic DOPED WITH Si
Y.Okamoto et al. (National Defence Academy, Yokosuka, Japan.) J. Jpn Sot. Powder Powder Metal., Vol 45, No 10, 1998,905-908. (In English.) Thermo-electric properties of Sic doped with Si were measured, with the object of reducing thermal conductivity, which decreases with increase in %Si. A figure of merit is calculated from thermo-electric power and thermal and electrical conductivities and is a maximum at 4O.Owt70Si.
Hard materials and too/ steels MECHANO-CHEMICAL SYNTHESIS NANOCRYSTALLINE TUNGSTEN CARBIDE POWDERS
OF
G.L.Tan, X.J.Wu. (Zhejiang University, Hangzhou, China.) Powder Metall., Vol 41, No 4, 1998,300-302. It is reported that nanocrystalline mixtures of WC, W,C and a non-stoichiometric carbide had been prepared by milling WO,-Mg-graphite powders. Two process steps are identified: reduction of WO, to ctW and synthesis of carbides. After milling for 50 hours at 250 rpm no WO, or C were detected by X-ray diffraction, leaving only carbides and MgO, which was removed by leaching with HCl. The final grain size was 4 to 20 nm.
THERMO-ELECTRIC PROPERTIES OF IRON SILICIDE MADE FROM SPRAY DRIED GRANULA TED POWDERS
CRACKING AND FRACTURE OF INDUSTRIAL DIAMOND PLATES
M.Ueda et al. (Sumitomo Special Metals Ltd, Osaka, Japan.) J. Jpn Sot. Powder Powder Metal., Vol 45, No 9, 1998, 866-871. (In Japanese.) FeSi, powders were produced by pulverization of vacuum melted ingots and granulated by spray drying to determine the feasibility of using the method for bulk powder production. Subsequent PM processing and thermo-electric properties are described.
R.W.Armstrong et al. (University of Maryland, USA.) Int. J. Refractory Metals Hard Mater., Vol 17, No 1-3, 1999, l-10. Deformation and cracking at edges of steel ball indentations in 1 mm thick diamond plates were investigated and followed by three-point bend tests on laser cut samples to study microstructural influences. Elastic moduli were estimated. Bend tests were modelled by
a finite element method. Fracture surfaces were shown to contain evidence of plastic deformation. ELECTRICAL MATERIALS
PROPERTIES
OF HARD
W.S.Williams. (124, Whispering Sands Drive, Sarasota, FL34242, USA.) Int. J. Refractory Metals Hard Mater., Vol 17, No l-3,1999,21-26. It is noted that carbides of some transition metals contain conduction electrons. Physical and mechanical properties, with underlying reasons, are discussed. It is suggested that there may be applications in microelectronics for these carbides, at elevated temperatures, in particular for non-stoichiometric compounds. TERNARY METAL BORON CARBIDES P.Rogl, H.Bittermann. (University of Vienna, Vienna, Austria.) Int. J. Refractory Metals Hard Mater., Vol 17, No l-3,1999,27-32. Ternary boron carbides, (Ti, Zr, Hf, V, WI-B-C, are discussed with regard to phase equilibria and crystallographic structures. Thermodynamic calculations are described and results are shown for partial systems containing metal and B,C, metal carbides and B,C, and metal boride-metal carbide systems. APPLICATION OF SOFT IMPRESSOR TECHNIQUE TO MEASUREMENT OF CREEP IN COVALENT METALS T.K.Harris et al. (University of Hull, Hull, UK.) Int. J. Refractory Metals Hard Mater., Vol 17, No l-3, 1999,33-38. It is reported that a soft indentor technique had been used to investigate indentation creep in single crystal diamond and polycrystalline cutting tools. The indentor was a cubic BN cone of 120” angle and is softer than diamond. The method is shown to yield measurements of mechanical properties at elevated temperatures. Dwell times were varied to change the extent of deformation. Measurable creep only occurred in the single crystals. EFFECT OF TEMPERATURE GRAIN SIZE AND COBALT CONTENT ON HARDNESS OF TUNGSTEN CARBIDE-COBALT
T.V.Milman et al. (Inst. for Problems in Materials Science, Kiev, Ukraine.) Znt. J. Refractory Metals Hard Mater., Vol 17, No l-3,1999,39-44. Vickers hardness was measured on WC-(10 to 24)vol%Co, with grain sizes of 0.5 to 2.3 ym, at -196 to 900°C. A HallPetch relationship was found between grain size and hardness. Up to 600°C the decrease in hardness was governed
MPR February 2000 37
PROCESSING AND EVALUATION OF COMPOSITE MANGANESE DIOXIDE AND CARBON BASED MATERIALS
PRESSURE, GREEN DENSITY AND STRENGTH OF THERMAL BATTERY PARTS
K.Terashita et al. (Osaka Prefecture University, Sakai, Japan.) J. Jpn Sot. Powder Powder Metal., Vol 45, No 9, 1998, 872-876 and 877-881. (In Japanese.) Studies of processing and properties of MnO,-C composite materials are described. The material is used as anodes in disc shaped Li batteries. A range of process operations were investigated with the object of standardizing the final product to give reliable battery performance.
G.Portal et al. (ASB Aerospatiale Batteries, Bourges, France.) Powder Metall., Vol42, No 1, 1999,34-40. Compressibilities of powders used in making thermal batteries, FeS, cathodes, solid LiCl-KC1 eutectic electrolyte and Li anodes were investigated. Densification was explained using Kawakita and Halldin models. Mechanical properties of were considered. Green compacts strength, which is shown to be sensitive to inter-particle contact area, increased linearly with pressure. EFFFECTS OF BINDER AND DEBINDING PARAMETERS ON RESIDUAL C IN NEODYMIUM-IRON-BORON
T.J.Moon et al. (Korea University, Seoul, Korea.) Powder Metall., Vol 42, No 1? 1999,41-44. Thermal debinding of injection moulded Nd-(Fe,Co)-B compacts was investigated for a range of binders and conditions. Residual C debinding depended on binder type, debinding technique and the molecular weight of the binder. H was the most appropriate atmosphere. Low residual C was favoured by slow heating and high debinding temperature. ANALYSIS OF PARTICLE ALIGNMENT DURING COMPACTION
H.Kodera et al. (Kyoto University, Kyoto, Japan.) J. Jpn Sot. Powder Powder Metal., Vol 45, No 9, 1998, 859-865. (In Japanese.) The behaviour of magnetic powder was modelled during compaction using Magneto-Cosserat-Continuum theory and FEMs to simulate alignment of particles. Relationships between magnetic field direction and different compaction conditions are analysed. The results are compared with those from particle dynamics simulations.
TEMPERATURE DEPENDENCE OF THERMO-ELECTRIC PROPERTIES OF Sic DOPED WITH Si
Y.Okamoto et al. (National Defence Academy, Yokosuka, Japan.) J. Jpn Sot. Powder Powder Metal., Vol 45, No 10, 1998,905-908. (In English.) Thermo-electric properties of Sic doped with Si were measured, with the object of reducing thermal conductivity, which decreases with increase in %Si. A figure of merit is calculated from thermo-electric power and thermal and electrical conductivities and is a maximum at 4O.Owt70Si.
Hard materials and too/ steels MECHANO-CHEMICAL SYNTHESIS NANOCRYSTALLINE TUNGSTEN CARBIDE POWDERS
OF
G.L.Tan, X.J.Wu. (Zhejiang University, Hangzhou, China.) Powder Metall., Vol 41, No 4, 1998,300-302. It is reported that nanocrystalline mixtures of WC, W,C and a non-stoichiometric carbide had been prepared by milling WO,-Mg-graphite powders. Two process steps are identified: reduction of WO, to ctW and synthesis of carbides. After milling for 50 hours at 250 rpm no WO, or C were detected by X-ray diffraction, leaving only carbides and MgO, which was removed by leaching with HCl. The final grain size was 4 to 20 nm.
THERMO-ELECTRIC PROPERTIES OF IRON SILICIDE MADE FROM SPRAY DRIED GRANULA TED POWDERS
CRACKING AND FRACTURE OF INDUSTRIAL DIAMOND PLATES
M.Ueda et al. (Sumitomo Special Metals Ltd, Osaka, Japan.) J. Jpn Sot. Powder Powder Metal., Vol 45, No 9, 1998, 866-871. (In Japanese.) FeSi, powders were produced by pulverization of vacuum melted ingots and granulated by spray drying to determine the feasibility of using the method for bulk powder production. Subsequent PM processing and thermo-electric properties are described.
R.W.Armstrong et al. (University of Maryland, USA.) Int. J. Refractory Metals Hard Mater., Vol 17, No 1-3, 1999, l-10. Deformation and cracking at edges of steel ball indentations in 1 mm thick diamond plates were investigated and followed by three-point bend tests on laser cut samples to study microstructural influences. Elastic moduli were estimated. Bend tests were modelled by
a finite element method. Fracture surfaces were shown to contain evidence of plastic deformation. ELECTRICAL MATERIALS
PROPERTIES
OF HARD
W.S.Williams. (124, Whispering Sands Drive, Sarasota, FL34242, USA.) Int. J. Refractory Metals Hard Mater., Vol 17, No l-3,1999,21-26. It is noted that carbides of some transition metals contain conduction electrons. Physical and mechanical properties, with underlying reasons, are discussed. It is suggested that there may be applications in microelectronics for these carbides, at elevated temperatures, in particular for non-stoichiometric compounds. TERNARY METAL BORON CARBIDES P.Rogl, H.Bittermann. (University of Vienna, Vienna, Austria.) Int. J. Refractory Metals Hard Mater., Vol 17, No l-3,1999,27-32. Ternary boron carbides, (Ti, Zr, Hf, V, WI-B-C, are discussed with regard to phase equilibria and crystallographic structures. Thermodynamic calculations are described and results are shown for partial systems containing metal and B,C, metal carbides and B,C, and metal boride-metal carbide systems. APPLICATION OF SOFT IMPRESSOR TECHNIQUE TO MEASUREMENT OF CREEP IN COVALENT METALS T.K.Harris et al. (University of Hull, Hull, UK.) Int. J. Refractory Metals Hard Mater., Vol 17, No l-3, 1999,33-38. It is reported that a soft indentor technique had been used to investigate indentation creep in single crystal diamond and polycrystalline cutting tools. The indentor was a cubic BN cone of 120” angle and is softer than diamond. The method is shown to yield measurements of mechanical properties at elevated temperatures. Dwell times were varied to change the extent of deformation. Measurable creep only occurred in the single crystals. EFFECT OF TEMPERATURE GRAIN SIZE AND COBALT CONTENT ON HARDNESS OF TUNGSTEN CARBIDE-COBALT
T.V.Milman et al. (Inst. for Problems in Materials Science, Kiev, Ukraine.) Znt. J. Refractory Metals Hard Mater., Vol 17, No l-3,1999,39-44. Vickers hardness was measured on WC-(10 to 24)vol%Co, with grain sizes of 0.5 to 2.3 ym, at -196 to 900°C. A HallPetch relationship was found between grain size and hardness. Up to 600°C the decrease in hardness was governed
MPR February 2000 37