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Crystal structure of acicular fine barium ferrite particles
Production of Co-ferrite particles from PFeOOH and PCo(OH),, by a solgel method, is described. NaOH is added to a suspension of PFeOOH and PCo(OH), containing small amounts of FeCl, and CoCl,, which was then heated at 40°C for 30 minutes and 80°C for a week to grow the Co ferrite particles, ELECTRICAL CONTACTS MADE FROM SILVER STANNATE-BISMUTH OXIDE K.Durst et a/. (Inst. Metali Niezelaznych, Gliwice, Poland.) Rudy Metale, Vo143, No 4. 1998, 185190. (In Polish.) Production, properties and applications of AgSnO,-Bi,,O, electrical contact materials are deschbed. It is shown that this material is a good substitute for the toxic Ag-Cd0 alloys. ELECTRICAL PROPERTIES OF MECHANICALLY ALLOYED RHENIUMSILICON ALLOY POWDER K.Minami ct cd. (Kinki University in Kyushu, Iizuka. Japan.) J. Jpn Sot. Powder Powder Metall., Vol 44, No 7, 1997, 658-660. (In Japanese. 1 Re-Si powders were ball milled in inert gas. The powders were mostly amorphized. X-ray diffraction showed the formation of ReSi, and Re,Si,. Consolidated alloys showed semi-conducting properties from ambient temperatures up to 200°C. CRYSTAL STRUCTURE OF ACICULAR FINE BARIUM FERRITE PARTICLES
MAGNETIC PROPERTIES OF SINTERED IRON-CHROMIUMMOLYRDENUM-SILICONPHOSPHORUS ALLOY
reinterpreted in the sent understanding.
T&to et al. (Daido Inst. of Technology, Nagoya, Japan.) J. Jpn Sot. Powder Powder Metall., Vol 44, No 7, 1997, 678685. (In Japanese.) It is reported that the addition of P to Fe-18%Cr-2%Mo-2CSi sintered magnets improves the magnetic properties. The optimum amounts were O.l5%P and 0.2clrP for DC and AC applications respectively. These are attributed to increase in grain size and decrease in porosity for DC and the formation of phosphide phase for AC.
Hard materials steels
and tool
PRODUCTION OF DIAMOND IMPREGNATED CUTTING TOOLS J.D.Dwan. (Inst. of Technology Tallaght, Dublin, Ireland.) Powder Metall., Vol41, No 2, 1998, 84-86. Production of diamond impregnated cutting t,ool materials by PM is outlined. The importance of process variables and their effect on service life is reviewed. Applications are described. DIAMOND GRINDING AND MACHINING OF METAL MATRIX COMPOSITE ENGINEERING COMPONENTS
K.Kakizaki. N.Hiratsuka. (Saitama University, Urawa, Japan.1 J. Jpn Sot. Powder Powder Metall., Vol 44, No 7, 1997,663-667. (In Japanese.) Acicular Ba ferrite, doped with Co and Ti was prepared by sintering. X-ray diffraction and electron microscopy showed that Co and Ti were incorporated in the Ba ferrite. The acicular particles were 1.0 pm by 0.09 JLrn, an aspect ration of 11:l.
M.W.Cook. (De Beers Industrial Diamond (UK) Ltd, Ascot, UK.) Powder Metall., Vol41, No 2, 19988789. It is noted that problems in machining metal matrix composites, due to presence of hard and brittle phases, can be overcome by use of superhard cutting tools. Polycrystalline diamond tools are suitable but tool and cutting conditions must be optimized to prevent rapid tool wear. Case studies are reviewed with regard to economic use of superhard tooling.
EFFECTS OF MECHANICAL ALLOYING ON MAGNETIC PROPERTIES OF SOFT NICKEL-ZINC FERRITE
lntermetallic
N.Oda et 01. (Fukuoka Inst. of Technology, Fukuoka, Japan.) J. Jpn Sot. Powder Powder Metall., Vol 44, NO 7,1997,668-673. (In Japanese. 1 Effects ofMA on magnetic properties of soft Ni-Zn ferrite were investigated. Raw materials were oxides of Ni, Zn and Fe. Spine1 synthesis started on heating at 300°C. MA materials showed increased permeability. This is attributed to lower density and numerous micropores. It is suggested that an improved material could be made if porosity could be reduced.
MECHANICAL ALUMINIDE
materials
PROPERTIES
OF IRON
I.Baker, P.R.Munroe. (University of New South Wales, Sydney. Australia.) Int. Materials Rev., Vol 42, No 5, 1997, 181205. Use of FeAl for structural applications in hostile environments at moderate temperatures is discussed. Vacancy retention after heat treatment and environmental embrittlement was not previously considered but has recently been taken into account. This allows a more complete understanding of the behaviour of FeAl. Older data is
light
of the
pre-
OXIDATION OF GLASS COATED LEAD TELLURIDE L.Chen et al. (Tohoku University, Sendai, Japan. 1 J Jpn Sot. Powder Powder Metall., Qol 44, No 7, 1997, 653. 657. (In Japanese. I It is reported that a glass coating improves the oxidation resistance of PbTe. Oxidation of coated and uncoated PbTe was investigated at 425 to 625°C under partial pressures of 0, from 10 Pa to 0.1 MPa. There was weight loss at low 0, pressures and high temperatures and weight gain at high 0, pressures and low temperatures. This is explained in terms of formation of Pb-Te-0 compounds.
Mechanical
alloying
SYNTHESIS OF LITHIUM-CARBON INTERCALATION COMPOUNDS BY MECHANICAL ALLOYING K.Nagano et al (Nagoya University, Nagoya, Japan.1 ?J. Jpn Sot. Powder Powder Metall., Vol 44, No 7, 1997, 706715. (In Japanese.) Formation of Li-C compounds by mechanical alloying of elemental Li and graphite powders was investigated. The milled powder was gold-like in colour. It is shown that the Li is taken into the layered structure of the graphite. The composition corresponds to LiC,j,, where the stable compound is LiC,;. A possible structure is proposed.
Metal
injection
moulding
HIGH PRESSURE WATER ATOMIZATION OF POWDER FOR METAL INJECTION MOULDING (Pacific K.Nakabayashi. Y.Tanaka, Metals Co Ltd, Kawaragi, Japan.) Powder Metall., Vol41, No 1,1998,47-50. Dependence of growth in use of MIM on availability of suitable powder and the cost are noted. It is reported that the use of high pressure water atomization for production of powder for MIM is being promoted and that this powder is suitable. The powders have low 0 content and high tap density. The technology to produce a range of ferrous powders is described. COMPARISON OF METAL INJECTION MOULDING OF ELEMENTAL AND ALLOYED COPPER-NICKEL POWDERS N.Wada et al. (Ritsumeikan University, Kusatsu, Japan.) J. Jpn Sot. Powder Powder Metall.. Vol 44, No 7, 1997, 596603. (In English. 1
MPR January 1999 37
MAGNETIC PROPERTIES OF SINTERED IRON-CHROMIUMMOLYRDENUM-SILICONPHOSPHORUS ALLOY
reinterpreted in the sent understanding.
T&to et al. (Daido Inst. of Technology, Nagoya, Japan.) J. Jpn Sot. Powder Powder Metall., Vol 44, No 7, 1997, 678685. (In Japanese.) It is reported that the addition of P to Fe-18%Cr-2%Mo-2CSi sintered magnets improves the magnetic properties. The optimum amounts were O.l5%P and 0.2clrP for DC and AC applications respectively. These are attributed to increase in grain size and decrease in porosity for DC and the formation of phosphide phase for AC.
Hard materials steels
and tool
PRODUCTION OF DIAMOND IMPREGNATED CUTTING TOOLS J.D.Dwan. (Inst. of Technology Tallaght, Dublin, Ireland.) Powder Metall., Vol41, No 2, 1998, 84-86. Production of diamond impregnated cutting t,ool materials by PM is outlined. The importance of process variables and their effect on service life is reviewed. Applications are described. DIAMOND GRINDING AND MACHINING OF METAL MATRIX COMPOSITE ENGINEERING COMPONENTS
K.Kakizaki. N.Hiratsuka. (Saitama University, Urawa, Japan.1 J. Jpn Sot. Powder Powder Metall., Vol 44, No 7, 1997,663-667. (In Japanese.) Acicular Ba ferrite, doped with Co and Ti was prepared by sintering. X-ray diffraction and electron microscopy showed that Co and Ti were incorporated in the Ba ferrite. The acicular particles were 1.0 pm by 0.09 JLrn, an aspect ration of 11:l.
M.W.Cook. (De Beers Industrial Diamond (UK) Ltd, Ascot, UK.) Powder Metall., Vol41, No 2, 19988789. It is noted that problems in machining metal matrix composites, due to presence of hard and brittle phases, can be overcome by use of superhard cutting tools. Polycrystalline diamond tools are suitable but tool and cutting conditions must be optimized to prevent rapid tool wear. Case studies are reviewed with regard to economic use of superhard tooling.
EFFECTS OF MECHANICAL ALLOYING ON MAGNETIC PROPERTIES OF SOFT NICKEL-ZINC FERRITE
lntermetallic
N.Oda et 01. (Fukuoka Inst. of Technology, Fukuoka, Japan.) J. Jpn Sot. Powder Powder Metall., Vol 44, NO 7,1997,668-673. (In Japanese. 1 Effects ofMA on magnetic properties of soft Ni-Zn ferrite were investigated. Raw materials were oxides of Ni, Zn and Fe. Spine1 synthesis started on heating at 300°C. MA materials showed increased permeability. This is attributed to lower density and numerous micropores. It is suggested that an improved material could be made if porosity could be reduced.
MECHANICAL ALUMINIDE
materials
PROPERTIES
OF IRON
I.Baker, P.R.Munroe. (University of New South Wales, Sydney. Australia.) Int. Materials Rev., Vol 42, No 5, 1997, 181205. Use of FeAl for structural applications in hostile environments at moderate temperatures is discussed. Vacancy retention after heat treatment and environmental embrittlement was not previously considered but has recently been taken into account. This allows a more complete understanding of the behaviour of FeAl. Older data is
light
of the
pre-
OXIDATION OF GLASS COATED LEAD TELLURIDE L.Chen et al. (Tohoku University, Sendai, Japan. 1 J Jpn Sot. Powder Powder Metall., Qol 44, No 7, 1997, 653. 657. (In Japanese. I It is reported that a glass coating improves the oxidation resistance of PbTe. Oxidation of coated and uncoated PbTe was investigated at 425 to 625°C under partial pressures of 0, from 10 Pa to 0.1 MPa. There was weight loss at low 0, pressures and high temperatures and weight gain at high 0, pressures and low temperatures. This is explained in terms of formation of Pb-Te-0 compounds.
Mechanical
alloying
SYNTHESIS OF LITHIUM-CARBON INTERCALATION COMPOUNDS BY MECHANICAL ALLOYING K.Nagano et al (Nagoya University, Nagoya, Japan.1 ?J. Jpn Sot. Powder Powder Metall., Vol 44, No 7, 1997, 706715. (In Japanese.) Formation of Li-C compounds by mechanical alloying of elemental Li and graphite powders was investigated. The milled powder was gold-like in colour. It is shown that the Li is taken into the layered structure of the graphite. The composition corresponds to LiC,j,, where the stable compound is LiC,;. A possible structure is proposed.
Metal
injection
moulding
HIGH PRESSURE WATER ATOMIZATION OF POWDER FOR METAL INJECTION MOULDING (Pacific K.Nakabayashi. Y.Tanaka, Metals Co Ltd, Kawaragi, Japan.) Powder Metall., Vol41, No 1,1998,47-50. Dependence of growth in use of MIM on availability of suitable powder and the cost are noted. It is reported that the use of high pressure water atomization for production of powder for MIM is being promoted and that this powder is suitable. The powders have low 0 content and high tap density. The technology to produce a range of ferrous powders is described. COMPARISON OF METAL INJECTION MOULDING OF ELEMENTAL AND ALLOYED COPPER-NICKEL POWDERS N.Wada et al. (Ritsumeikan University, Kusatsu, Japan.) J. Jpn Sot. Powder Powder Metall.. Vol 44, No 7, 1997, 596603. (In English. 1
MPR January 1999 37