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Characterization of silver and silver-palladium powders produced by wire explosion
PM
TRIBOLOGICAL PROPERTIES OF RAPIDLY SOLIDIFIED TERNARY ALUMINIUM-SILICON ALLOYS
K. Kondoh, Y. Takeda, ( S u m i t o m o Electric Industries Ltd, Itami City, J a p a n ) . The tribological properties of hypereutectic A1-Si alloys were discussed a n d a t t e m p t s to improve wear a n d seizure resistance were described. Use was m a d e of a step-wise loading w e a r t e s t rig. The additions of t r a n s i t i o n e l e m e n t s a n d use of rapidly solidified powders were r e p o r t e d to greatly improve seizure resistance. FINE POWDERS AND COATINGS OF ALUMINIUM ALLOY COMPOSITES MADE BY PLASMA SPRAYING
K.& Khor et al (Nanyang Technological University, Singapore). An investigation of t h e properties of A1Li a n d A1-Ti sprayed powders a n d coatings were described. An Ai-Li/SiC composite was shown to give fusion of b o t h c o m p o n e n t s resulting in a single composite particle. The microstructures were shown to be featureless, dendritic, cellular or m a r t e n s i t i c d e p e n d i n g on conditions. E F F E C T S OF ALLOY COMPOSITION AND ALLOYING METHOD ON SINTERED ALUMINIUM ALLOYS
S. Miura et al (Showa Denko Kk, Tokyo, Japan). T h e p r o p e r t i e s of PM alloys w e r e d i s c u s s e d w i t h r e s p e c t to t h e l i m i t e d ductility imposed by t h e presence of Al308 particles r e m a i n i n g from t h e oxides film on AI powder. The d e v e l o p m e n t of a PM A1-SiMg-Cu/SiC alloy w i t h good m e c h a n i c a l properties was reported. The Mg:Si ratio w a s correlated with m e c h a n i c a l properties. A r a n g e of p r o d u c t i o n u n i t p r o c e s s e s including powder blending and master alloy m e t h o d s were studied.
N e w powders MATERIAL WITH STABLE DIMENSIONAL CHANGES I N D E P E N D E N T OF INTERNAL DENSITY VARIATIONS
C. Lindberg et al (HSganfis AB, H5ganfis, Sweden). I n t e r n a l variations in green density a n d r e s u l t a n t variations in shrinkage d u r i n g sintering were discussed with respect to t h e difficulty in a t t a i n i n g good d i m e n s i o n a l tolerances in complex s h a p e d components. It was r e p o r t e d t h a t a new material subject to lower d i m e n s i o n a l changes h a d been developed. PRODUCTION OF ELECTROLYTIC IRON POWDER FROM SPONGE IRON F I N E S
R.R. Dash et al (National Metallurgical Laboratory, J a m s h e d p u r , India).
40 MPR January 1994
LITERATURE
REVIEW
It was r e p o r t e d t h a t electrolytic Fe powders h a d been p r o d u c e d from sponge Fe used as t h e a n o d e in a ferrous chloride electrolyte. The mechanical properties of t h e c o n s o l i d a t e d p o w d e r were used to indicate the p o t e n t i a l of t h e powder for t h e p r o d u c t i o n of p a r t s w i t h a d e q u a t e mechanical properties. P R O P E R T I E S OF S E G R E G A T I O N F R E E POWDERS
H. Suzuki et al (Kobe Steel Ltd, Hyogo, Japan). A new b l e n d i n g t e c h n i q u e w h i c h gave reduced segregation in m i x e d powders was described. The a d d i t i o n of a n o r g a n i c binder was reported to prevent segregation of g r a p h i t e by b i n d i n g t h e alloy a d d i t i o n s to t h e steel or Fe powder. Ejection pressures were also said to be reduced. POWDERS FOR HIGH PERFORMANCE STEELS
C. Lingberg et al (HSgangts, Sweden). New a p p l i c a t i o n s for PM steels were discussed with reference to p a r t design, materials p r o p e r t i e s a n d t h e a t t a i n m e n t of close d i m e n s i o n a l tolerances. The p a p e r described newly developed steels w h i c h combined high strength with close d i m e n s i o n a l tolerance. The steels were b a s e d on p a r t i a l l y or fully p r e a l l o y e d p o w d e r s a n d t e n s i l e s t r e n g t h s u p to 900 MPa were reported.
such as MoS2. The characteristics of t h e materials containing t h e coated powders were superior to those m a d e with u n c o a t e d l u b r i c a n t powders. MAGNETIC P R O P E R T I E S OF CHROMIUM A N D MANGANESE POWDERS
A.A. Shatov et al (Steel a n d Alloys Institute, Moscow, Russia). The m a g n e t i c p r o p e r t i e s of Mn a n d Cr powders m a d e by ball milling electrolytic Mn or Cr w e r e d e s c r i b e d . The v a l u e s of susceptibility o b t a i n e d were s h o w n to be due to t h e presence of Fe from t h e balls used a n d Fe from t h e stainless steel mill. CHARACTERIZATION OF SILVER AND SILVER-PALLADIUM POWDERS P R O D U C E D BY WIRE EXPLOSION
)L Kato et al (Kyushi University, Fukuoka, Japan). An investigation of Ag a n d Ag-30% Pd powders, m a d e by wire explosion, was d e s c r i b e d . Two t y p e s of p a r t i c l e w e r e found. Larger particles, several p m in size, were formed by solidification of droplets a n d ultrafine particles formed from vapour. C r y s t a l l i t e sizes w e r e 80 t o 190 nm. The Ag-Pd alloy was shown to be a solid solution.
Hot and cold isostatic pressing
MECHANICAL P R O P E R T I E S OF S I N T E R E D PARTS MADE FROM N E W LOW ALLOY PREALLOYED POWDERS
HOT ISOSTATIC P R E S S I N G OF PLASMA SPRAYED TITANIUM ALUMINIDE COATINGS
M. Yoshida et al (Kobe Steel Ltd Hyogo, Japan). The p a p e r described t h e m e c h a n i c a l properties of a 1% Mo-05% Ni PM steel m a d e from a novel prealloyed powder. The r e p o r t e d properties were, sintered density 7.46gm/cm 3, tensile s t r e n g t h 833 MPa a n d fatigue limit 530 MPa. The powder was said to have high compressibility.
I~A_ Khor et al (Nanyang Technological University, Singapore). HIP was r e p o r t e d to have been used to densify coatings o f TiA1. E l e c t r o n microscopy with analytical facilities was used to characterize the structures. I m p r o v e m e n t s in m e c h a n i c a l p r o p e r t i e s were r e p o r t e d . The grain sizes s h o w e d significant variations and pores were shown to be reduced in size.
E F F E C T S OF PARTICLE SIZE AND SHAPE ON CHARACTERISTICS OF LOW CHLORINE TITANIUM POWDERS
R. M u r a y a m a et al (Toho T i t a n i u m Co Ltd, Osaka, J a p a n ) . It was r e p o r t e d t h a t a Ti powder with a very low C1 c o n t e n t h a d been produced. Powder characteristics were described a n d correlated with particle size and morphology. APPLICATIONS OF METAL COATED COMPOSITE POWDERS FOR PM MATERIALS
C.Y. Narusawa, (Nippon Mining Co Ltd, Tokyo, J a p a n ) . It was r e p o r t e d t h a t m e t a l coatings h a d been applied to powders of solid lubricants,
HOT ISOSTATIC P R E S S I N G AND P R O P E R T I E S OF SILICON CARBIDEALUMINIUM NITRIDE MATERIALS
J-F. Li et al (Tohoku University, Sendal, Japan). It was r e p o r t e d t h a t HIP a t 200 MPa a n d 1950°C densified SiC to only 93%. Full density was a t t a i n e d in presence of a d d e d A1N at a lower t e m p e r a t u r e if t h e powder m i x t u r e was specially prepared. The SiCA1N s h o w e d improved mechanical properties. APPLICATION OF HOT ISOSTATIC P R E S S I N G TO PREPARATION OF SINTERED STEELS
J. Karwan-Baczewska et al (University of Mining a n d Metallurgy, Crakow, Poland).
TRIBOLOGICAL PROPERTIES OF RAPIDLY SOLIDIFIED TERNARY ALUMINIUM-SILICON ALLOYS
K. Kondoh, Y. Takeda, ( S u m i t o m o Electric Industries Ltd, Itami City, J a p a n ) . The tribological properties of hypereutectic A1-Si alloys were discussed a n d a t t e m p t s to improve wear a n d seizure resistance were described. Use was m a d e of a step-wise loading w e a r t e s t rig. The additions of t r a n s i t i o n e l e m e n t s a n d use of rapidly solidified powders were r e p o r t e d to greatly improve seizure resistance. FINE POWDERS AND COATINGS OF ALUMINIUM ALLOY COMPOSITES MADE BY PLASMA SPRAYING
K.& Khor et al (Nanyang Technological University, Singapore). An investigation of t h e properties of A1Li a n d A1-Ti sprayed powders a n d coatings were described. An Ai-Li/SiC composite was shown to give fusion of b o t h c o m p o n e n t s resulting in a single composite particle. The microstructures were shown to be featureless, dendritic, cellular or m a r t e n s i t i c d e p e n d i n g on conditions. E F F E C T S OF ALLOY COMPOSITION AND ALLOYING METHOD ON SINTERED ALUMINIUM ALLOYS
S. Miura et al (Showa Denko Kk, Tokyo, Japan). T h e p r o p e r t i e s of PM alloys w e r e d i s c u s s e d w i t h r e s p e c t to t h e l i m i t e d ductility imposed by t h e presence of Al308 particles r e m a i n i n g from t h e oxides film on AI powder. The d e v e l o p m e n t of a PM A1-SiMg-Cu/SiC alloy w i t h good m e c h a n i c a l properties was reported. The Mg:Si ratio w a s correlated with m e c h a n i c a l properties. A r a n g e of p r o d u c t i o n u n i t p r o c e s s e s including powder blending and master alloy m e t h o d s were studied.
N e w powders MATERIAL WITH STABLE DIMENSIONAL CHANGES I N D E P E N D E N T OF INTERNAL DENSITY VARIATIONS
C. Lindberg et al (HSganfis AB, H5ganfis, Sweden). I n t e r n a l variations in green density a n d r e s u l t a n t variations in shrinkage d u r i n g sintering were discussed with respect to t h e difficulty in a t t a i n i n g good d i m e n s i o n a l tolerances in complex s h a p e d components. It was r e p o r t e d t h a t a new material subject to lower d i m e n s i o n a l changes h a d been developed. PRODUCTION OF ELECTROLYTIC IRON POWDER FROM SPONGE IRON F I N E S
R.R. Dash et al (National Metallurgical Laboratory, J a m s h e d p u r , India).
40 MPR January 1994
LITERATURE
REVIEW
It was r e p o r t e d t h a t electrolytic Fe powders h a d been p r o d u c e d from sponge Fe used as t h e a n o d e in a ferrous chloride electrolyte. The mechanical properties of t h e c o n s o l i d a t e d p o w d e r were used to indicate the p o t e n t i a l of t h e powder for t h e p r o d u c t i o n of p a r t s w i t h a d e q u a t e mechanical properties. P R O P E R T I E S OF S E G R E G A T I O N F R E E POWDERS
H. Suzuki et al (Kobe Steel Ltd, Hyogo, Japan). A new b l e n d i n g t e c h n i q u e w h i c h gave reduced segregation in m i x e d powders was described. The a d d i t i o n of a n o r g a n i c binder was reported to prevent segregation of g r a p h i t e by b i n d i n g t h e alloy a d d i t i o n s to t h e steel or Fe powder. Ejection pressures were also said to be reduced. POWDERS FOR HIGH PERFORMANCE STEELS
C. Lingberg et al (HSgangts, Sweden). New a p p l i c a t i o n s for PM steels were discussed with reference to p a r t design, materials p r o p e r t i e s a n d t h e a t t a i n m e n t of close d i m e n s i o n a l tolerances. The p a p e r described newly developed steels w h i c h combined high strength with close d i m e n s i o n a l tolerance. The steels were b a s e d on p a r t i a l l y or fully p r e a l l o y e d p o w d e r s a n d t e n s i l e s t r e n g t h s u p to 900 MPa were reported.
such as MoS2. The characteristics of t h e materials containing t h e coated powders were superior to those m a d e with u n c o a t e d l u b r i c a n t powders. MAGNETIC P R O P E R T I E S OF CHROMIUM A N D MANGANESE POWDERS
A.A. Shatov et al (Steel a n d Alloys Institute, Moscow, Russia). The m a g n e t i c p r o p e r t i e s of Mn a n d Cr powders m a d e by ball milling electrolytic Mn or Cr w e r e d e s c r i b e d . The v a l u e s of susceptibility o b t a i n e d were s h o w n to be due to t h e presence of Fe from t h e balls used a n d Fe from t h e stainless steel mill. CHARACTERIZATION OF SILVER AND SILVER-PALLADIUM POWDERS P R O D U C E D BY WIRE EXPLOSION
)L Kato et al (Kyushi University, Fukuoka, Japan). An investigation of Ag a n d Ag-30% Pd powders, m a d e by wire explosion, was d e s c r i b e d . Two t y p e s of p a r t i c l e w e r e found. Larger particles, several p m in size, were formed by solidification of droplets a n d ultrafine particles formed from vapour. C r y s t a l l i t e sizes w e r e 80 t o 190 nm. The Ag-Pd alloy was shown to be a solid solution.
Hot and cold isostatic pressing
MECHANICAL P R O P E R T I E S OF S I N T E R E D PARTS MADE FROM N E W LOW ALLOY PREALLOYED POWDERS
HOT ISOSTATIC P R E S S I N G OF PLASMA SPRAYED TITANIUM ALUMINIDE COATINGS
M. Yoshida et al (Kobe Steel Ltd Hyogo, Japan). The p a p e r described t h e m e c h a n i c a l properties of a 1% Mo-05% Ni PM steel m a d e from a novel prealloyed powder. The r e p o r t e d properties were, sintered density 7.46gm/cm 3, tensile s t r e n g t h 833 MPa a n d fatigue limit 530 MPa. The powder was said to have high compressibility.
I~A_ Khor et al (Nanyang Technological University, Singapore). HIP was r e p o r t e d to have been used to densify coatings o f TiA1. E l e c t r o n microscopy with analytical facilities was used to characterize the structures. I m p r o v e m e n t s in m e c h a n i c a l p r o p e r t i e s were r e p o r t e d . The grain sizes s h o w e d significant variations and pores were shown to be reduced in size.
E F F E C T S OF PARTICLE SIZE AND SHAPE ON CHARACTERISTICS OF LOW CHLORINE TITANIUM POWDERS
R. M u r a y a m a et al (Toho T i t a n i u m Co Ltd, Osaka, J a p a n ) . It was r e p o r t e d t h a t a Ti powder with a very low C1 c o n t e n t h a d been produced. Powder characteristics were described a n d correlated with particle size and morphology. APPLICATIONS OF METAL COATED COMPOSITE POWDERS FOR PM MATERIALS
C.Y. Narusawa, (Nippon Mining Co Ltd, Tokyo, J a p a n ) . It was r e p o r t e d t h a t m e t a l coatings h a d been applied to powders of solid lubricants,
HOT ISOSTATIC P R E S S I N G AND P R O P E R T I E S OF SILICON CARBIDEALUMINIUM NITRIDE MATERIALS
J-F. Li et al (Tohoku University, Sendal, Japan). It was r e p o r t e d t h a t HIP a t 200 MPa a n d 1950°C densified SiC to only 93%. Full density was a t t a i n e d in presence of a d d e d A1N at a lower t e m p e r a t u r e if t h e powder m i x t u r e was specially prepared. The SiCA1N s h o w e d improved mechanical properties. APPLICATION OF HOT ISOSTATIC P R E S S I N G TO PREPARATION OF SINTERED STEELS
J. Karwan-Baczewska et al (University of Mining a n d Metallurgy, Crakow, Poland).