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Vibrational compaction of hard deformed powder materials
Powder
production
PROGRESS
IN MATERIALS
J.Bill, F.Aldinger. (Max Planck Inst., Stuttgart, Germany.) Z Metallkunde, Vol 87, No 11, 1996, 827-840. Synthesis of novel materials is reviewed. Nano-scale ceramic powders and new approaches to colloidal processing are considered. Liquid phase sintering of and SiC is discussed. PAl,O:, Investigations of synthesis of precursors for ceramic materials are described
EVALUATION OF FINE POWDER PARTICLE DISPERSIONS ON COMPOSITE POWDER SURFACES K.Terashita et al. (University of Osaka Prefecture, Sakai, Japan.) JJapan Sot. Powder and Powder Metalfur@, Vol 42, No 9, 1995, 986-991. (In Japanese.) Production of composite powders by dry coating 0.2 pm particles on the surface of 12 pm particles is reported. Distribution of the ultrafine particles on the core particles was investigated by X-ray diffraction and scanning electron microscopy with image analysis.
together with thin films, coatings and bulk materials. properties were also studied.
Pressing
PRODUCTION OF ULTRFAFINE AMORPHOUS IRON-PDOSPHORUS POWDERS BY A PLASMA METHOD
SHOCK COMPACTION OF ALUMINIUMMAGNESIUM-SILICON-OXIDE SPHERES
S.M.Huang et al. (Nanjing University, China.) J. Materials Science, Vol 30, No 11, 1995, 291 l-2920. It is reported that ultrafine amorphous Fe-P powders had been made by a plasma technique from cyclopenlyl Fe and PC13. Powders were 40 to 200 nm in size, spherical and contained about 32at%P. Some residual Cl and P enrichment were found in particle surfaces. Mechanism of particle formation is discussed in the light of powder characteristics.
P.Zivanovic et al. (Serbian Academy of Sciences and Arts, Yugoslavia.) J Materials Science, Vol 30, No 11, 1996, 2960-
SYNTHESIS
PREPARATION OF ULTRAFINE NICKEL POWDER BY HYDROTHERMAL REDUCTION OF NICKEL HYDROXIDE HLian. (Academica Sinica, China.) Huagong Yejin, Vol 16, No 4, 1995, 307-310. (In Chinese.) Production of ultrafine Ni powder by hydrothermal reduction of Ni (OH) 2 slurry with an anthraquinone catalyst was described. Influences of process conditions on reaction rate were determined by X-ray diffraction and particle size by scanning electron microscopy. Powders had a mean size of 300 nm and spherical morphology DEVELOPMENT OF AUTOMATED PROCESS FOR MANUFACTURE OF STEEL POWDERS D.Takai, Ylkai. (Kobe Steel Ltd., Takasago, Japan.) .I.Japan Sot. Powder and Powder Metallurm Vol 42, No 9, 1995, 975-981. (In Japanese.) It is reported that a new automated steel powder production facility had suceeded in increasing productivity by a factor of 3 and reducing variability in powder and part characteristics. The atomization based facility is described with aid of flow charts.
38
MPR
July/August
1997
A NEW DIE WALL SYSTEM
2955. It is reported that Al-Mg-8-O powders had been compacted by a projectile, with a velocity of 1655 msec~‘, the dynamic pressure being 8 GW. The compacts were formed from layers of powders in two particle sizes, 100 to 200 pm and 200 to 315 pm. About 10% liquation was found in the larger particles. The Vicker’s microhardness in the consolidated zones was 120 compared with 70 for the powder. The smaller particles did not density due to low tendency to form inter-particle bonds. INFLUENCE OF OPERATING TEMPERATURE ON SHRINK PRESSURE OF PM DIES
FITTING
G.F.Bocchini et al. (Hogan& Italia Sri, Rapallo, Italy.) Powder Metallurm, Vol 39, No 3, 1996, 195-206. Reasons and proceedures for shrink fitting of parts of PM dies are discussed with regard to temperture effects and the calculations involved in enstiring no loss of strength. It is noted that the introduction of warm compaction may result in safety limits being exceeded. A critical analysis of the changes from room temperature to warm compaction is presented. Design data for dies is established the object being to avoid die failure during use. The predictions were tested on a range of materials. BALANCED DIE METHOD POWDER COMPACTION
It is reported that ejection pressures have been reduced by use of a balanced die method of compaction. The approach was to use a thin wall die with a rubber sleeve which is capable of transmitting a radial pressure. Maintainance of a balance between internal compaction pressure and external bolstering pressure reduced ejection pressure almost to zero. Production of compacts 32 mm in diameter by 20 mm long at green densities of 6.49 g.cm-3 was reported for Fe powder at low compaction pressure.
FOR METAL
B.P.Holownia. (Loughborough University of Technology, Loughborough, UK.) Powder Metallurgv, Vol 39, No 3, 1996, 207-209.
LUBRICATION
W.G.Ball et al. (Zinc Corp of America, Ypislanti, Michigan, USA.) Znt. ,I Powder Metallur@, Vol 33, No 1, 1997, 23-30. Development of a dry powder lubricant applicator to apply lubricant to die walls for pressing high density Fe and steel parts from lubricant free powders was reported. The device was adapted from one used in die casting. VIBRATTONAL COMPACTION OF HARD DEFORMED POWDER MATERIALS Ylvlev et al. Poroshkovaya MetallurRiya, No 3/4, 1996, 1 l-15. (In Russian.) Features of densification of hard deformed powder by pulsed pressing are considered. The effectiveness of the process is shown to depend on the magnitude of the applied forces. Experimental and predicted data arc compared. ROLLING OF POWDER COMPOSITES REINFORCED WITH MESH L.H.Vishnykov et al. Poroshkovaya Metallurgiya, No 3/4, 1996, 15-18. (In Russian.) Consolidation of powder, reinforced with mesh, by rolling, was investigated. Relationships between the presence of the mesh, density, strip thickness and rolling parameters were established. BEHAVIOUR OF NON-CIRCULAR PARTICLES DURING COMPACTION A MAGNETIC FIELD
IN
H.Kotera et al. (Kyoto University, Kyoto, Japan.) J.Japan Sot. Powder and Powder MetaUur@, Vol 42, No 9, 1995, 1019-1026. (In Japanese.) Simulation of compaction of non-circular particles in an applied magnetic field is described. It is shown how ellipsoidal ferromagnetic powders are aligned in an easy magnetization direction during isostatic compaction. Aspects of the behaviour of non-circular particles are elucidated.
production
PROGRESS
IN MATERIALS
J.Bill, F.Aldinger. (Max Planck Inst., Stuttgart, Germany.) Z Metallkunde, Vol 87, No 11, 1996, 827-840. Synthesis of novel materials is reviewed. Nano-scale ceramic powders and new approaches to colloidal processing are considered. Liquid phase sintering of and SiC is discussed. PAl,O:, Investigations of synthesis of precursors for ceramic materials are described
EVALUATION OF FINE POWDER PARTICLE DISPERSIONS ON COMPOSITE POWDER SURFACES K.Terashita et al. (University of Osaka Prefecture, Sakai, Japan.) JJapan Sot. Powder and Powder Metalfur@, Vol 42, No 9, 1995, 986-991. (In Japanese.) Production of composite powders by dry coating 0.2 pm particles on the surface of 12 pm particles is reported. Distribution of the ultrafine particles on the core particles was investigated by X-ray diffraction and scanning electron microscopy with image analysis.
together with thin films, coatings and bulk materials. properties were also studied.
Pressing
PRODUCTION OF ULTRFAFINE AMORPHOUS IRON-PDOSPHORUS POWDERS BY A PLASMA METHOD
SHOCK COMPACTION OF ALUMINIUMMAGNESIUM-SILICON-OXIDE SPHERES
S.M.Huang et al. (Nanjing University, China.) J. Materials Science, Vol 30, No 11, 1995, 291 l-2920. It is reported that ultrafine amorphous Fe-P powders had been made by a plasma technique from cyclopenlyl Fe and PC13. Powders were 40 to 200 nm in size, spherical and contained about 32at%P. Some residual Cl and P enrichment were found in particle surfaces. Mechanism of particle formation is discussed in the light of powder characteristics.
P.Zivanovic et al. (Serbian Academy of Sciences and Arts, Yugoslavia.) J Materials Science, Vol 30, No 11, 1996, 2960-
SYNTHESIS
PREPARATION OF ULTRAFINE NICKEL POWDER BY HYDROTHERMAL REDUCTION OF NICKEL HYDROXIDE HLian. (Academica Sinica, China.) Huagong Yejin, Vol 16, No 4, 1995, 307-310. (In Chinese.) Production of ultrafine Ni powder by hydrothermal reduction of Ni (OH) 2 slurry with an anthraquinone catalyst was described. Influences of process conditions on reaction rate were determined by X-ray diffraction and particle size by scanning electron microscopy. Powders had a mean size of 300 nm and spherical morphology DEVELOPMENT OF AUTOMATED PROCESS FOR MANUFACTURE OF STEEL POWDERS D.Takai, Ylkai. (Kobe Steel Ltd., Takasago, Japan.) .I.Japan Sot. Powder and Powder Metallurm Vol 42, No 9, 1995, 975-981. (In Japanese.) It is reported that a new automated steel powder production facility had suceeded in increasing productivity by a factor of 3 and reducing variability in powder and part characteristics. The atomization based facility is described with aid of flow charts.
38
MPR
July/August
1997
A NEW DIE WALL SYSTEM
2955. It is reported that Al-Mg-8-O powders had been compacted by a projectile, with a velocity of 1655 msec~‘, the dynamic pressure being 8 GW. The compacts were formed from layers of powders in two particle sizes, 100 to 200 pm and 200 to 315 pm. About 10% liquation was found in the larger particles. The Vicker’s microhardness in the consolidated zones was 120 compared with 70 for the powder. The smaller particles did not density due to low tendency to form inter-particle bonds. INFLUENCE OF OPERATING TEMPERATURE ON SHRINK PRESSURE OF PM DIES
FITTING
G.F.Bocchini et al. (Hogan& Italia Sri, Rapallo, Italy.) Powder Metallurm, Vol 39, No 3, 1996, 195-206. Reasons and proceedures for shrink fitting of parts of PM dies are discussed with regard to temperture effects and the calculations involved in enstiring no loss of strength. It is noted that the introduction of warm compaction may result in safety limits being exceeded. A critical analysis of the changes from room temperature to warm compaction is presented. Design data for dies is established the object being to avoid die failure during use. The predictions were tested on a range of materials. BALANCED DIE METHOD POWDER COMPACTION
It is reported that ejection pressures have been reduced by use of a balanced die method of compaction. The approach was to use a thin wall die with a rubber sleeve which is capable of transmitting a radial pressure. Maintainance of a balance between internal compaction pressure and external bolstering pressure reduced ejection pressure almost to zero. Production of compacts 32 mm in diameter by 20 mm long at green densities of 6.49 g.cm-3 was reported for Fe powder at low compaction pressure.
FOR METAL
B.P.Holownia. (Loughborough University of Technology, Loughborough, UK.) Powder Metallurgv, Vol 39, No 3, 1996, 207-209.
LUBRICATION
W.G.Ball et al. (Zinc Corp of America, Ypislanti, Michigan, USA.) Znt. ,I Powder Metallur@, Vol 33, No 1, 1997, 23-30. Development of a dry powder lubricant applicator to apply lubricant to die walls for pressing high density Fe and steel parts from lubricant free powders was reported. The device was adapted from one used in die casting. VIBRATTONAL COMPACTION OF HARD DEFORMED POWDER MATERIALS Ylvlev et al. Poroshkovaya MetallurRiya, No 3/4, 1996, 1 l-15. (In Russian.) Features of densification of hard deformed powder by pulsed pressing are considered. The effectiveness of the process is shown to depend on the magnitude of the applied forces. Experimental and predicted data arc compared. ROLLING OF POWDER COMPOSITES REINFORCED WITH MESH L.H.Vishnykov et al. Poroshkovaya Metallurgiya, No 3/4, 1996, 15-18. (In Russian.) Consolidation of powder, reinforced with mesh, by rolling, was investigated. Relationships between the presence of the mesh, density, strip thickness and rolling parameters were established. BEHAVIOUR OF NON-CIRCULAR PARTICLES DURING COMPACTION A MAGNETIC FIELD
IN
H.Kotera et al. (Kyoto University, Kyoto, Japan.) J.Japan Sot. Powder and Powder MetaUur@, Vol 42, No 9, 1995, 1019-1026. (In Japanese.) Simulation of compaction of non-circular particles in an applied magnetic field is described. It is shown how ellipsoidal ferromagnetic powders are aligned in an easy magnetization direction during isostatic compaction. Aspects of the behaviour of non-circular particles are elucidated.