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Synthesis of ultrafine composite nickel-titanium carbide powders
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POWDER PRODUCTION PRODUCTION OF TIN POWDERS BY ULTRASONIC ATOMIZATION A N D SOLID STATE TRANSFORMATION
A_D. Styrkas and R.A. Oganyan, (Academy of Sciences, Moscow, Russia), Powder Metall., Vol 35, No 2, 1992, 117-119. The use of ultrasonic atomization to produce powders with a high proportion of f i n e s is d e s c r i b e d . The p o w d e r was thermally cycled to low temperatures to allow the white Sn/grey Sn reaction to break up the particles. Lower levels of c o n t a m i n a t i o n t h a n for m e c h a n i c a l l y comminuted powders are reported and the specific surface is double that of atomized and four times that of atomized and milled powders. PARTICLE SIZE M E A S U R E M E N T USING NON-INVASIVE DIELECTRIC SENSORS
S.I.R. Simons and R.A~ Williams, (UMIST, Manchester, UK), Powder Technology, Vol 73, No 1, 1992, 85-90. A non-invasive technique for particle size determination, based on measurements of capacitance, is described. Results are compared with m e a s u r e m e n t s m a d e by conventional methods. SYNTHESIS OF ULTRAFINE COMPOSITE NICKEL-TITANIUM CARBIDE POWDERS
S. Ohno et al, (National Research Inst for Metals, TokYo, Japan), J Japan Soc Powder and Powder Metallurgy, Vol 39, No 3, 1992, 221-226. (In Japanese). The production of ultrafine composite Ni-TiC powders by reactive plasma metal reaction is described. The process involves arc melting, evaporation and deposition of the alloys in a mixture of H and Ar at 0.1 M P a . S t r u c t u r e , composition, morphology and sintering characteristics were assessed. The powders are reported to contain Ni, TiC and Ni~Ti. PREPARATION OF MONOSIZED TITANIUM OXIDE POWDERS
M. ¥okota and M. Naka, (Osaka University, Osaka, Japan), J Japan Soe Powder and Powder Metallurgy, Vol 38, No 3, 1992, 235238. (In Japanese). The production of uniformly sized TiO2 by p r e c i p i t a t i o n of T i ( O H ) 4 f r o m Ti sulphate solution by urea and ultrasonic vibration is described. The Ti(OH)4 was
50 MPR March 1993
LITERATURE
REVIEW
calcined to yield TIO22. The particle size is reported to be reduced by the use of ultrasonic vibration. PRODUCTION OF MOLYBDENUM AND T U N G S T E N POWDERS BY SPARK DISCHARGE IN WATER OR OIL
A. Saito et al, (Ritsumeikan University, Kyoto, Japan), J Japan Soc Powder and Powder Metallurgy, Vol 39, No 7, 1992, 542545. (In Japanese). It is that Mo and W powders had been produced by spark discharge in de-ionized water or silicone oil using rotating disk and wire electrodes. In water the Mo particles were s p h e r i c a l or i r r e g u l a r and were c o n t a m i n a t e d w i t h MoO3 a n d t h e W particles were spherical and contained WaO particles. In oil, spherical Mo or W particles were formed contaminated with Mo2C or W3C and SiC.
PRESSING MULTIPLATEN SYSTEMS FOR MECHANICAL P R E S S E S
G. Krumpholz, (Dorst-Maschinen und Anlagenbau, Kochel am See, Germany), Powder Metall Int, Vol 24, No 1, 1992, 303-304. The technology of co-axial pressing on m u l t i p l a t e n presses is d i s c u s s e d w i t h reference to powder transfer, compaction and de-moulding. Economic and quality aspects are considered. COMPACTION MECHANISMS FOR ULTRAFINE SILICON CARBIDE POWDERS
R. Vassen and D. StSver, (Forschungszent r u m Jfilich, Jfilich, Germany), Powder Technology, Vol 72, No 3, 1992, 223226.Cold uniaxial compacting of ultrafine SiC powders containing excess Si was investigated at pressures 102 to l0 s MPa. A wide range of green density was covered the initial powder density being 0.7 to 1%. Density was correlated with compaction pressure and a parameter, dependent on powder particle size and die materials, is deduced. A mechanism is proposed. D E F E C T HEALING DURING SINTERHIP
A_ Frisch, (Max Planck Inst, Stuttgart, Germany), Z fiir Metallkunde, Vol 83, No 1, 1992, 3-10. The process of sinterHIP is discussed a n d r e f e r e n c e is m a d e to e n h a n c e d
densification by a liquid phase and the formation of macropores by separation of grains and liquid phase. Elimination of artificially formed spherical pores in W-Ni was studied, use being m a d e of load dilatometry. Defect healing m e c h a n i s m s are compared with visco-elastic models. Phase separation is shown to occur mainly in coarse grained materials or where there is grain growth during HIP. Pore healing is d i s c u s s e d w i t h r e f e r e n c e to h e a l i n g diagrams which indicate mechanisms for different pore sizes u n d e r specific HIP conditions.
SlNTERING UNCONVENTIONAL M E T H O D S OF SINTERING IN POWDER METALLURGYJ.
Lezanski, (Inst. Gorniczo-Hutnicza, Krakow, Poland), Metall Proszkow, Vol 25, No 2, 1992, 54-66. (In Polish). Unconventional methods of sintering are reviewed. Two categories are identified, sintering with and without pressure. The first group includes activated sintering, liquid phase sintering and infiltration and the second, repressing, CIP and HIP, consolidation by a t m o s p h e r i c pressure, injection moulding, spray forming and deformation by extrusion, rolling, etc.
FUNDAMENTALS SPECIFIC SURFACE AND PARTICLE SIZES OF CARBONYL IRON POWDER
Y.K. K u z m i n a et al, P o r o s h k o v a y a Metallurgiya, No 9, 1991, 94-98. (In Russian). A device for the measurement of the mean diameter of carbonyl Fe particles, based on gas filtration through a layer of powder, is described. Good agreement with microscopic m e t h o d s is reported. It is suggested that the method is suitable for the study of specific surface, particle size and for quality control.
PRODUCTS" Aluminium E F F E C T S OF ALUMINA FIBRE CONTENT ON P R O P E R T I E S OF ALUMINIUM ALLOY METAL MATRIX COMPOSITE
KW. Kaczmzar and I~U. Kainer, (Technical University, Clausthal-Zellerfeld, Germany),
POWDER PRODUCTION PRODUCTION OF TIN POWDERS BY ULTRASONIC ATOMIZATION A N D SOLID STATE TRANSFORMATION
A_D. Styrkas and R.A. Oganyan, (Academy of Sciences, Moscow, Russia), Powder Metall., Vol 35, No 2, 1992, 117-119. The use of ultrasonic atomization to produce powders with a high proportion of f i n e s is d e s c r i b e d . The p o w d e r was thermally cycled to low temperatures to allow the white Sn/grey Sn reaction to break up the particles. Lower levels of c o n t a m i n a t i o n t h a n for m e c h a n i c a l l y comminuted powders are reported and the specific surface is double that of atomized and four times that of atomized and milled powders. PARTICLE SIZE M E A S U R E M E N T USING NON-INVASIVE DIELECTRIC SENSORS
S.I.R. Simons and R.A~ Williams, (UMIST, Manchester, UK), Powder Technology, Vol 73, No 1, 1992, 85-90. A non-invasive technique for particle size determination, based on measurements of capacitance, is described. Results are compared with m e a s u r e m e n t s m a d e by conventional methods. SYNTHESIS OF ULTRAFINE COMPOSITE NICKEL-TITANIUM CARBIDE POWDERS
S. Ohno et al, (National Research Inst for Metals, TokYo, Japan), J Japan Soc Powder and Powder Metallurgy, Vol 39, No 3, 1992, 221-226. (In Japanese). The production of ultrafine composite Ni-TiC powders by reactive plasma metal reaction is described. The process involves arc melting, evaporation and deposition of the alloys in a mixture of H and Ar at 0.1 M P a . S t r u c t u r e , composition, morphology and sintering characteristics were assessed. The powders are reported to contain Ni, TiC and Ni~Ti. PREPARATION OF MONOSIZED TITANIUM OXIDE POWDERS
M. ¥okota and M. Naka, (Osaka University, Osaka, Japan), J Japan Soe Powder and Powder Metallurgy, Vol 38, No 3, 1992, 235238. (In Japanese). The production of uniformly sized TiO2 by p r e c i p i t a t i o n of T i ( O H ) 4 f r o m Ti sulphate solution by urea and ultrasonic vibration is described. The Ti(OH)4 was
50 MPR March 1993
LITERATURE
REVIEW
calcined to yield TIO22. The particle size is reported to be reduced by the use of ultrasonic vibration. PRODUCTION OF MOLYBDENUM AND T U N G S T E N POWDERS BY SPARK DISCHARGE IN WATER OR OIL
A. Saito et al, (Ritsumeikan University, Kyoto, Japan), J Japan Soc Powder and Powder Metallurgy, Vol 39, No 7, 1992, 542545. (In Japanese). It is that Mo and W powders had been produced by spark discharge in de-ionized water or silicone oil using rotating disk and wire electrodes. In water the Mo particles were s p h e r i c a l or i r r e g u l a r and were c o n t a m i n a t e d w i t h MoO3 a n d t h e W particles were spherical and contained WaO particles. In oil, spherical Mo or W particles were formed contaminated with Mo2C or W3C and SiC.
PRESSING MULTIPLATEN SYSTEMS FOR MECHANICAL P R E S S E S
G. Krumpholz, (Dorst-Maschinen und Anlagenbau, Kochel am See, Germany), Powder Metall Int, Vol 24, No 1, 1992, 303-304. The technology of co-axial pressing on m u l t i p l a t e n presses is d i s c u s s e d w i t h reference to powder transfer, compaction and de-moulding. Economic and quality aspects are considered. COMPACTION MECHANISMS FOR ULTRAFINE SILICON CARBIDE POWDERS
R. Vassen and D. StSver, (Forschungszent r u m Jfilich, Jfilich, Germany), Powder Technology, Vol 72, No 3, 1992, 223226.Cold uniaxial compacting of ultrafine SiC powders containing excess Si was investigated at pressures 102 to l0 s MPa. A wide range of green density was covered the initial powder density being 0.7 to 1%. Density was correlated with compaction pressure and a parameter, dependent on powder particle size and die materials, is deduced. A mechanism is proposed. D E F E C T HEALING DURING SINTERHIP
A_ Frisch, (Max Planck Inst, Stuttgart, Germany), Z fiir Metallkunde, Vol 83, No 1, 1992, 3-10. The process of sinterHIP is discussed a n d r e f e r e n c e is m a d e to e n h a n c e d
densification by a liquid phase and the formation of macropores by separation of grains and liquid phase. Elimination of artificially formed spherical pores in W-Ni was studied, use being m a d e of load dilatometry. Defect healing m e c h a n i s m s are compared with visco-elastic models. Phase separation is shown to occur mainly in coarse grained materials or where there is grain growth during HIP. Pore healing is d i s c u s s e d w i t h r e f e r e n c e to h e a l i n g diagrams which indicate mechanisms for different pore sizes u n d e r specific HIP conditions.
SlNTERING UNCONVENTIONAL M E T H O D S OF SINTERING IN POWDER METALLURGYJ.
Lezanski, (Inst. Gorniczo-Hutnicza, Krakow, Poland), Metall Proszkow, Vol 25, No 2, 1992, 54-66. (In Polish). Unconventional methods of sintering are reviewed. Two categories are identified, sintering with and without pressure. The first group includes activated sintering, liquid phase sintering and infiltration and the second, repressing, CIP and HIP, consolidation by a t m o s p h e r i c pressure, injection moulding, spray forming and deformation by extrusion, rolling, etc.
FUNDAMENTALS SPECIFIC SURFACE AND PARTICLE SIZES OF CARBONYL IRON POWDER
Y.K. K u z m i n a et al, P o r o s h k o v a y a Metallurgiya, No 9, 1991, 94-98. (In Russian). A device for the measurement of the mean diameter of carbonyl Fe particles, based on gas filtration through a layer of powder, is described. Good agreement with microscopic m e t h o d s is reported. It is suggested that the method is suitable for the study of specific surface, particle size and for quality control.
PRODUCTS" Aluminium E F F E C T S OF ALUMINA FIBRE CONTENT ON P R O P E R T I E S OF ALUMINIUM ALLOY METAL MATRIX COMPOSITE
KW. Kaczmzar and I~U. Kainer, (Technical University, Clausthal-Zellerfeld, Germany),