- Email: [email protected]
Production of ultrafine iron-nickel-boron powders by reduction with boro-hydride
PM
POWDER P R O D U C T I O N PURIFICATION OF MOLYBDI~NUM POWDERS AND OXIDES BY M ~ G N E T I C SEPARATION
G S. B u r n k a n o v et al. (Academy of Sciences CIS Vysokochistyie Veshchestva, No 2, 1991, 133-138_ (In Russian). The use of h i g h g r a d i e n t m a g n e t i c separation to purify powders of Mo metal, oxides and salts is described. It is r e p o r t e d t h a t i m p u r i t y inclusions containing Fe a n d Si are efficiently removed a n d t h a t t h e s e make up half of the magnetic fraction. The balance of the magnetic portion removed c o n t a i n s A1, Cut, Mg, Ti a n d o t h e r impurities. PRODUCTION OF PARTLY ALLOYED IRON POWDERS
V.B. Akimenko et al, (Central Scientific Research Inst for Ferrous Metallurgy), Stal No 1, 1991, (In Russian). The p r o d u c t i o n of partly prealloyed Fe powders, in which particles of t h e alloy elements are sintered onto t h e surface of the Fe particles, is described. Addition of Ni, Cu a n d Mo are considered. The effects of temperature on diffusion-reduction a n n e a l i n g , t h e c o m p a t i b i l i t y of t h e p o w d e r s , s t r e n g t h of t h e c o m p a c t s , m i c r o s t r u c t u r e s a n d d i s t r i b u t i o n of t h e alloy elements are illustrated and discussed. PREPARATION OF FINE CARBIDE POWDERS BY VAPOUR PHASE REACTION
S-S, Kim, H-S, Kim, (InHa Uni Incheon, Korea). J. Korean Inst. of Metals, Vol 29, No 7, 1991, 659-664, (In Korean). The p r o d u c t i o n of fine WC powder by v a p o u r p h a s e reaction between WC16, C3H s a n d H2, in t h e range 700 to 1200°C is described. The effects of process conditions on particles size a n d m o r p h o l o g y were investigated. At temperatures above l l 0 0 ° C only WC is produced. At 1200°C t h e particles are spherical a n d 0.02 ~m in size. P a r t i c l e a n d c r y s t a l l i t e sizes are r e p o r t e d to d e c r e a s e w i t h i n c r e a s e in reaction t e m p e r a t u r e . PREPARATION OF FINE CARBIDE POWDERS BY VAPOUR PHASE REACTION
S-S, Kim, H-S, Kim, (InHa Uni, lncheon,
LITERATURE
REVIEW
Korea), J. Korean Inst. of Metals, Vol 29, No 7, 1991, 659-664. (In Korean). The p r o d u c t i o n of fine WC powder by v a p o u r p h a s e reaction between WC16, C2H4 a n d H2, in t h e range 800 to 1300°C is described, X-ray diffraction a n d electron microscopy were used to characterize the effects of process variables on yield and particle size and morphology. The p r o p o r t i o n of WC in t h e p r o d u c t is r e p o r t e d to increase with t e m p e r a t u r e up to 95% at ll00°C. At l l 0 0 ° C t h e particles are spherical in s h a p e a n d a b o u t 0.007 p m in size. The particles size was found to be i n v e r s e l y p r o p o r t i o n a l to t h e r e a c t i o n t e m p e r a t u r e a n d t h e size of p a r t i c l e a g g r e g a t e s to i n c r e a s e l i n e a r l y w i t h temperature. E F F E C T OF ASPIRATION P R E S S U R E ON GAS NOZZLE G E O M E T R Y AND SPRAYING C O N D I T I O N IN CONFINED GAS ATOMIZATION
H.C. Lee et at, (Seoul National Uni, Seoul, Korea). J. Korean Inst, of Metals, Vol 29, No 7, 1991, 680-687, (In Korean). The use of gas atomization for p r o d u c t i o n of powder a n d bulk m e t a l at cooling r a t e s of 102 to 103°C/sec is discussed. The p a p e r describes a study of t h e effects of process parameters, m e t a l a n d gas flow and aspiration pressure. Aspiration p r e s s u r e was m e a s u r e d as a function of atomization geometry. A model for e s t i m a t i o n of operating regine which i n t e r r e l a t e s t h e p r o c e s s p a r a m e t e r s is introduced. PRODUCTION OF ULTRAFINE IRONNICKEL-BORON POWDERS BY REDUCTION WITH BORO-HYDRIDE
Z. Hu e t al, ( N a n j i n g U n i , C h ] n a ) . J. Applied Physics, Vol 70, No 1, 436-438. The p r o d u c t i o n of ultrafine powders of Fe-B, Ni-B a n d Fe-Ni-B by reaction between metal ions in aqueous solution with borohydride is described. The p r o p o r t i o n of Fe a n d Ni in t h e t e r n a r y powder could be varied by changing t h e ratio of Fe a n d Ni ions in t h e solution b u t t h e c o n c e n t r a t i o n of B r e m a i n e d c o n s t a n t w h e n the borohydride c o n t e n t was low. The powders are shown to be mainly a m o r p h o u s a n d t h e particle morphology was irregular. Particle sizes were in t h e range 3 0 _ 5 nm_ High resolution electron microscopy showed t h a t t h e particles were partially crystalline to a d e p t h of 5 n m a n d t h e core to be fully amorphous.
PREPARATION OF BULK QUASICRYSTALLINE SAMPLES
Z. C h e n et al, ( C e n t r a l S o u t h Uni of Technology, China), J. Central South Uni of Technology, China, Vol 21, No 1, 1991, 46-51. (In chinese). A method, using r a p i d solidification, for the p r o d u c t i o n of quasicrystalline A1 alloy powders, containing a single isocahedral phase, is described. The isocahedral p h a s e is found in A1-Mn, A1-Cr a n d A1-Mn-Cr p o w d e r s w h e n t h e c o o l i n g r a t e is c o n t r o l l e d . T h e i s o c a h e d r a l p h a s e is retained w h e n t h e powders are explosively c o m p a c t e d a n d t h e p r o p e r t i e s of t h e compacts are given. CLASSIFICATION OF T U N G S T E N POWDER FOR IMPROVEMENTS IN EMISSIVITY OF BARIATED T U N G S T E N ELECTRODES
H.Li et al, (Central South Uni of Technology, C h i n a ) , J. Central South Uni of Technology, China, Vol 21, No l, 1991, 52-58, (In Chinese). A fluidizing t e c h n i q u e was used for t h e p r e p a r a t i o n of W powder. It is r e p o r t e d t h a t t h e m e t h o d avoids agglomeration of t h e W particles a n d t h u s keeps t h e powder more uniformly sized a n d more suitable for t h e p r o d u c t i o n of b a r i a t e d W c a t h o d e s for e l e c t r o n i c s a p p l i c a t i o n . It is s u g g e s t e d t h a t t h e m e t h o d could be applied to o t h e r metal powders. TECHNOLOGY AND FACILITIES FOR THE PRODUCTION OF ULTRAFINE POWDERS
S.B. Lasday, (Ultrafine Powder Technolgoy, Ayer, Maine, USA), Industrial Heating, Vol 58, No 6, 1991, 17-19. The p a p e r gives a n a c c o u n t of t h e t e c h n o l o g y a n d a d e s c r i p t i o n of t h e facilities for t h e p r o d u c t i o n of a range of ultrafine metal powders using tandem atomization. The process is r e p o r t e d to give h i g h e r y i e l d s a n d p o w d e r s w i t h improved properties. The d e v e l o p m e n t of t a n d e m a t o m i z a t i o n is outlined. PRODUCTION OF TITANIUM ALLOY POWDERS BY ROTATING ELECTRODE PROCESS
IC Isohishi et al, (Nippon Steel Welding Products a n d Engineering, J a p a n ) , J. Iron and Steel Inst. Japan, Vol 76, No 12, 1990, 2108-2115, (In J a p a n e s e ) . The a p p l i c a t i o n of REP a n d p l a s m a REP to the p r o d u c t i o n of Ti-6A]-4V, Ti-Ni, Ti-Fe
MPR May 1992 79
POWDER P R O D U C T I O N PURIFICATION OF MOLYBDI~NUM POWDERS AND OXIDES BY M ~ G N E T I C SEPARATION
G S. B u r n k a n o v et al. (Academy of Sciences CIS Vysokochistyie Veshchestva, No 2, 1991, 133-138_ (In Russian). The use of h i g h g r a d i e n t m a g n e t i c separation to purify powders of Mo metal, oxides and salts is described. It is r e p o r t e d t h a t i m p u r i t y inclusions containing Fe a n d Si are efficiently removed a n d t h a t t h e s e make up half of the magnetic fraction. The balance of the magnetic portion removed c o n t a i n s A1, Cut, Mg, Ti a n d o t h e r impurities. PRODUCTION OF PARTLY ALLOYED IRON POWDERS
V.B. Akimenko et al, (Central Scientific Research Inst for Ferrous Metallurgy), Stal No 1, 1991, (In Russian). The p r o d u c t i o n of partly prealloyed Fe powders, in which particles of t h e alloy elements are sintered onto t h e surface of the Fe particles, is described. Addition of Ni, Cu a n d Mo are considered. The effects of temperature on diffusion-reduction a n n e a l i n g , t h e c o m p a t i b i l i t y of t h e p o w d e r s , s t r e n g t h of t h e c o m p a c t s , m i c r o s t r u c t u r e s a n d d i s t r i b u t i o n of t h e alloy elements are illustrated and discussed. PREPARATION OF FINE CARBIDE POWDERS BY VAPOUR PHASE REACTION
S-S, Kim, H-S, Kim, (InHa Uni Incheon, Korea). J. Korean Inst. of Metals, Vol 29, No 7, 1991, 659-664, (In Korean). The p r o d u c t i o n of fine WC powder by v a p o u r p h a s e reaction between WC16, C3H s a n d H2, in t h e range 700 to 1200°C is described. The effects of process conditions on particles size a n d m o r p h o l o g y were investigated. At temperatures above l l 0 0 ° C only WC is produced. At 1200°C t h e particles are spherical a n d 0.02 ~m in size. P a r t i c l e a n d c r y s t a l l i t e sizes are r e p o r t e d to d e c r e a s e w i t h i n c r e a s e in reaction t e m p e r a t u r e . PREPARATION OF FINE CARBIDE POWDERS BY VAPOUR PHASE REACTION
S-S, Kim, H-S, Kim, (InHa Uni, lncheon,
LITERATURE
REVIEW
Korea), J. Korean Inst. of Metals, Vol 29, No 7, 1991, 659-664. (In Korean). The p r o d u c t i o n of fine WC powder by v a p o u r p h a s e reaction between WC16, C2H4 a n d H2, in t h e range 800 to 1300°C is described, X-ray diffraction a n d electron microscopy were used to characterize the effects of process variables on yield and particle size and morphology. The p r o p o r t i o n of WC in t h e p r o d u c t is r e p o r t e d to increase with t e m p e r a t u r e up to 95% at ll00°C. At l l 0 0 ° C t h e particles are spherical in s h a p e a n d a b o u t 0.007 p m in size. The particles size was found to be i n v e r s e l y p r o p o r t i o n a l to t h e r e a c t i o n t e m p e r a t u r e a n d t h e size of p a r t i c l e a g g r e g a t e s to i n c r e a s e l i n e a r l y w i t h temperature. E F F E C T OF ASPIRATION P R E S S U R E ON GAS NOZZLE G E O M E T R Y AND SPRAYING C O N D I T I O N IN CONFINED GAS ATOMIZATION
H.C. Lee et at, (Seoul National Uni, Seoul, Korea). J. Korean Inst, of Metals, Vol 29, No 7, 1991, 680-687, (In Korean). The use of gas atomization for p r o d u c t i o n of powder a n d bulk m e t a l at cooling r a t e s of 102 to 103°C/sec is discussed. The p a p e r describes a study of t h e effects of process parameters, m e t a l a n d gas flow and aspiration pressure. Aspiration p r e s s u r e was m e a s u r e d as a function of atomization geometry. A model for e s t i m a t i o n of operating regine which i n t e r r e l a t e s t h e p r o c e s s p a r a m e t e r s is introduced. PRODUCTION OF ULTRAFINE IRONNICKEL-BORON POWDERS BY REDUCTION WITH BORO-HYDRIDE
Z. Hu e t al, ( N a n j i n g U n i , C h ] n a ) . J. Applied Physics, Vol 70, No 1, 436-438. The p r o d u c t i o n of ultrafine powders of Fe-B, Ni-B a n d Fe-Ni-B by reaction between metal ions in aqueous solution with borohydride is described. The p r o p o r t i o n of Fe a n d Ni in t h e t e r n a r y powder could be varied by changing t h e ratio of Fe a n d Ni ions in t h e solution b u t t h e c o n c e n t r a t i o n of B r e m a i n e d c o n s t a n t w h e n the borohydride c o n t e n t was low. The powders are shown to be mainly a m o r p h o u s a n d t h e particle morphology was irregular. Particle sizes were in t h e range 3 0 _ 5 nm_ High resolution electron microscopy showed t h a t t h e particles were partially crystalline to a d e p t h of 5 n m a n d t h e core to be fully amorphous.
PREPARATION OF BULK QUASICRYSTALLINE SAMPLES
Z. C h e n et al, ( C e n t r a l S o u t h Uni of Technology, China), J. Central South Uni of Technology, China, Vol 21, No 1, 1991, 46-51. (In chinese). A method, using r a p i d solidification, for the p r o d u c t i o n of quasicrystalline A1 alloy powders, containing a single isocahedral phase, is described. The isocahedral p h a s e is found in A1-Mn, A1-Cr a n d A1-Mn-Cr p o w d e r s w h e n t h e c o o l i n g r a t e is c o n t r o l l e d . T h e i s o c a h e d r a l p h a s e is retained w h e n t h e powders are explosively c o m p a c t e d a n d t h e p r o p e r t i e s of t h e compacts are given. CLASSIFICATION OF T U N G S T E N POWDER FOR IMPROVEMENTS IN EMISSIVITY OF BARIATED T U N G S T E N ELECTRODES
H.Li et al, (Central South Uni of Technology, C h i n a ) , J. Central South Uni of Technology, China, Vol 21, No l, 1991, 52-58, (In Chinese). A fluidizing t e c h n i q u e was used for t h e p r e p a r a t i o n of W powder. It is r e p o r t e d t h a t t h e m e t h o d avoids agglomeration of t h e W particles a n d t h u s keeps t h e powder more uniformly sized a n d more suitable for t h e p r o d u c t i o n of b a r i a t e d W c a t h o d e s for e l e c t r o n i c s a p p l i c a t i o n . It is s u g g e s t e d t h a t t h e m e t h o d could be applied to o t h e r metal powders. TECHNOLOGY AND FACILITIES FOR THE PRODUCTION OF ULTRAFINE POWDERS
S.B. Lasday, (Ultrafine Powder Technolgoy, Ayer, Maine, USA), Industrial Heating, Vol 58, No 6, 1991, 17-19. The p a p e r gives a n a c c o u n t of t h e t e c h n o l o g y a n d a d e s c r i p t i o n of t h e facilities for t h e p r o d u c t i o n of a range of ultrafine metal powders using tandem atomization. The process is r e p o r t e d to give h i g h e r y i e l d s a n d p o w d e r s w i t h improved properties. The d e v e l o p m e n t of t a n d e m a t o m i z a t i o n is outlined. PRODUCTION OF TITANIUM ALLOY POWDERS BY ROTATING ELECTRODE PROCESS
IC Isohishi et al, (Nippon Steel Welding Products a n d Engineering, J a p a n ) , J. Iron and Steel Inst. Japan, Vol 76, No 12, 1990, 2108-2115, (In J a p a n e s e ) . The a p p l i c a t i o n of REP a n d p l a s m a REP to the p r o d u c t i o n of Ti-6A]-4V, Ti-Ni, Ti-Fe
MPR May 1992 79