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Hydrogen reduction of ammonium paratugstate (APT) into tungsten blue oxide (TBO)
POWDER PRODUCTION H Y D R O G E N R E D U C T I O N OF AMMONIUM PARATUGSTATE (APT) INTO T U N G S T E N B L U E O X I D E ( T B O )
J.W.van Put., T.W.Zegers, (Dellt UniversiW of Technology. Delft, The Netherlands,) Int. J.
Refractory Metals and Hard Materials, Vol 10, No 3, 1991, 115 122. The literature relating to ~he reduction of APT into TBO, at 300 lo 600 C is c r i t i c a l l y reviewed. A m m o n i a c o n t e n t , oxygen index, specific surface area and Fischer mean particle size are discussed and reported to be typical characteristics of TBO.
H Y D R O G E N R E D U C T I O N OF AMMONIUM PARATUNGSTATE (APT) INTO T U N G S T E N B L U E O X I D E ( T B O )
J.W.van Pul et al. Int. J. Refractory Metals and Hard Materials, Vol 10, No 3, 1991, 123 131. An investigation into the effects of changes in process p a r a m e l e r s for the II reduction of APT on the properties of TBO is described. Reduction time, temperature, it flow rate and yield of p o w d e r are considered as t h e s e influence a m m o n i a content, oxygen index and specific surface area of the TBO. II was not found possible to change the Fishcher mean particle size significantly by c h a n g e in one of t h e operating conditions.
PRODUCTION AND C H A R A C T E R I S A T I O N OF HYDROGENREDUCED SUBMICRON TUNGSTEN P O W D E R S -- PART I
W.D.Schubert, E.Lassner. (Technical University of Vienna, Vienna, Austria.) Int. J.
Refractory Metals and Hard Materials, Vol 10, No 3, 1991, 133 141. The production and characterisation of fine W powders is discussed with particular reference to state of the art techniques.
RECOVERY OF T A N T A L U M A N D N I O B I U M FROM S O L U T I O N S A F T E R CRYSTALLISATION OF A M M O N I U M PARATUNGSTATE (APT)
T.Zhengji, (Cemented Carbide Industry Co., Zhuzhou, ttunan, China.) Int. J. Refractory Metals and Hard Materials, 10, No 3, 1991, 143-146.
The production of Ta and Nb from t h e residual solutions after crystallisation a n d removal of APT is described. The process involves and the addition of NaDH a n d heating with agitation at 100°C which precipitates Na niobates and tantalates. The precipitate is t r e a t e d with HC1, dried and calcined to yield Nb and Ta oxides.
P R O P E R T I E S OF S T E E L P R O D U C E D BY DISCHARGE BETWEEN STEEL ELECTRODES AND ELECTROLYTE
R.A.Valiev et al. Poroshkovaya Metallurgiya, No 6, 1991, 4 6. (In Russian.) The process of making powder by low temperature plasma discharge between steel electrodes and an aqueous electrolyte is d e s c r i b e d . The e f f e c t s o f p r o c e s s c o n d i t i o n s on t h e d i s p e r s i v i t y a n d composition of the powders are stated. The presence of Fe304 in the powders is reported.
E L E C T R O P R E C I P I T A T I O N OF U L T R A F I N E IRON-COBALT ALLOY P O W D E R S
E.P.Zhelibo et al. Poroshkovaya Metallurgiya, No 6, 1991, 35-40. (In Russian.) The electrolylic p r o d u c t i o n of Fe-Co alloy powders in a complex electrolyte is described. Process conditions and variations are considered. The Co c o n t e n t of the powder is reported to increase with i n c r e a s e s in t h e Co c o n t e n t of t h e electrolyte. Co r i c h p o w d e r s are characterised by increased dispersion and higher values of magnetic induction and coercive force.
T R E A T M E N T OF WASTE T U N G S T E N HARD ALLOYS BY T H E ZINC M E T H O D
V.A_Cristyaova, V.A.Popov, Tsvet, Met., No 2, 1991, 47-48. (In Russian.) The application of the Zn m e t h o d for the t r e a t m e n t of W bearing waste materials is discussed. The m e t h o d is based on the reaction between Zn and Co in c e m e n t e d carbides and investigation of the effects of Co c o n t e n t a n d WC p a n i c l e size is described.
N E W P R O C E S S E S FOR T H E M A N U F A C T U R E OF PM ALUMINIUM PRODUCTS
V.G.Gopienko et al, Tswet. Met., No 2, 1991, 56-60. (In Russian.)
Techniques for the atomization of A1 and A1 alloys are reviewed. Gas and w a t e r atomization and rapid solidification are considered. Use of mechanical comminution and ultrasonic vibration in the atomization process are discussed.
P R O D U C T I O N OF T I T A N I U M A N D T I T A N I U M A L U M I N I D E P O W D E R S BY C A L C I O T H E R M I C R E D U C T I O N OF OXIDES
R. Suzuki et al. (Kyoto UniversiW, Japan.) Zairyo to Purosesu, Vol 2, No 2, 1991, 322 323, (In Japanese.) Ti, Ti3Al and TiA1 powders were m a d e by calciothermic reduction of Ti and Al oxides at 900 ° to 1000°C, Ca(OH)2 was removed by leaching with HC1 or acetic acid for the c o m p o u n d s . C o n c e n t r a t i o n of r e s i d u a l oxides in the powders are stated.
P R O C E S S I N G OF U L T R A F I N E P O W D E R S BY E L E C T R O N BEAM EVAPORATION
ICl.Lawson, D2.Stephenson, (Cranfield Institute of Technology, Bedfordshire, England.) J. Materials Science, Letters, Vol 10, No 12, 1991, 699-700. It is r e p o r t e d t h a t u l t r a f i n e m e t a l powders below 100 nm in size have been produced by a t h r e e - b e a m high p r e s s u r e electron beam technique in which there is a high degree of gas scattering. Variation in p a r t i c l e m o r p h o l o g y of Ni p o w d e r is described.
P R E S E N T STATE OF M A N U F A C T U R E OF A M O R P H O U S PM M A T E R I A L S
M.Miskovieova et al. (Ustave Exptl. Metal, 8AV, Kosice, Poland.) Pokroky Pra,skove Metalurgie, No 1-2, 1991, 34-49. (In Polish.) The production of a m o r p h o u s powder metallic materials is reviewed with respect to i m p r o v e m e n t s in p r o p e r t i e s w h i c h accrue from their use. Fre, Al, Ni, Ti, Nb and Si are considered for use in machinery, aerospace and electro-technical applications.
P R O G R E S S I V E T E C H N O L O G I E S IN POWDER M E T A L L U R G Y
M.Miskovicova et al. (Ustav exptl, Metal, SAV, Kosice, Poland.) Pokroky Praskove Metalurgie, No 1-2, 1991, 50-66. (In Polish.)
MPR June 1992 47
J.W.van Put., T.W.Zegers, (Dellt UniversiW of Technology. Delft, The Netherlands,) Int. J.
Refractory Metals and Hard Materials, Vol 10, No 3, 1991, 115 122. The literature relating to ~he reduction of APT into TBO, at 300 lo 600 C is c r i t i c a l l y reviewed. A m m o n i a c o n t e n t , oxygen index, specific surface area and Fischer mean particle size are discussed and reported to be typical characteristics of TBO.
H Y D R O G E N R E D U C T I O N OF AMMONIUM PARATUNGSTATE (APT) INTO T U N G S T E N B L U E O X I D E ( T B O )
J.W.van Pul et al. Int. J. Refractory Metals and Hard Materials, Vol 10, No 3, 1991, 123 131. An investigation into the effects of changes in process p a r a m e l e r s for the II reduction of APT on the properties of TBO is described. Reduction time, temperature, it flow rate and yield of p o w d e r are considered as t h e s e influence a m m o n i a content, oxygen index and specific surface area of the TBO. II was not found possible to change the Fishcher mean particle size significantly by c h a n g e in one of t h e operating conditions.
PRODUCTION AND C H A R A C T E R I S A T I O N OF HYDROGENREDUCED SUBMICRON TUNGSTEN P O W D E R S -- PART I
W.D.Schubert, E.Lassner. (Technical University of Vienna, Vienna, Austria.) Int. J.
Refractory Metals and Hard Materials, Vol 10, No 3, 1991, 133 141. The production and characterisation of fine W powders is discussed with particular reference to state of the art techniques.
RECOVERY OF T A N T A L U M A N D N I O B I U M FROM S O L U T I O N S A F T E R CRYSTALLISATION OF A M M O N I U M PARATUNGSTATE (APT)
T.Zhengji, (Cemented Carbide Industry Co., Zhuzhou, ttunan, China.) Int. J. Refractory Metals and Hard Materials, 10, No 3, 1991, 143-146.
The production of Ta and Nb from t h e residual solutions after crystallisation a n d removal of APT is described. The process involves and the addition of NaDH a n d heating with agitation at 100°C which precipitates Na niobates and tantalates. The precipitate is t r e a t e d with HC1, dried and calcined to yield Nb and Ta oxides.
P R O P E R T I E S OF S T E E L P R O D U C E D BY DISCHARGE BETWEEN STEEL ELECTRODES AND ELECTROLYTE
R.A.Valiev et al. Poroshkovaya Metallurgiya, No 6, 1991, 4 6. (In Russian.) The process of making powder by low temperature plasma discharge between steel electrodes and an aqueous electrolyte is d e s c r i b e d . The e f f e c t s o f p r o c e s s c o n d i t i o n s on t h e d i s p e r s i v i t y a n d composition of the powders are stated. The presence of Fe304 in the powders is reported.
E L E C T R O P R E C I P I T A T I O N OF U L T R A F I N E IRON-COBALT ALLOY P O W D E R S
E.P.Zhelibo et al. Poroshkovaya Metallurgiya, No 6, 1991, 35-40. (In Russian.) The electrolylic p r o d u c t i o n of Fe-Co alloy powders in a complex electrolyte is described. Process conditions and variations are considered. The Co c o n t e n t of the powder is reported to increase with i n c r e a s e s in t h e Co c o n t e n t of t h e electrolyte. Co r i c h p o w d e r s are characterised by increased dispersion and higher values of magnetic induction and coercive force.
T R E A T M E N T OF WASTE T U N G S T E N HARD ALLOYS BY T H E ZINC M E T H O D
V.A_Cristyaova, V.A.Popov, Tsvet, Met., No 2, 1991, 47-48. (In Russian.) The application of the Zn m e t h o d for the t r e a t m e n t of W bearing waste materials is discussed. The m e t h o d is based on the reaction between Zn and Co in c e m e n t e d carbides and investigation of the effects of Co c o n t e n t a n d WC p a n i c l e size is described.
N E W P R O C E S S E S FOR T H E M A N U F A C T U R E OF PM ALUMINIUM PRODUCTS
V.G.Gopienko et al, Tswet. Met., No 2, 1991, 56-60. (In Russian.)
Techniques for the atomization of A1 and A1 alloys are reviewed. Gas and w a t e r atomization and rapid solidification are considered. Use of mechanical comminution and ultrasonic vibration in the atomization process are discussed.
P R O D U C T I O N OF T I T A N I U M A N D T I T A N I U M A L U M I N I D E P O W D E R S BY C A L C I O T H E R M I C R E D U C T I O N OF OXIDES
R. Suzuki et al. (Kyoto UniversiW, Japan.) Zairyo to Purosesu, Vol 2, No 2, 1991, 322 323, (In Japanese.) Ti, Ti3Al and TiA1 powders were m a d e by calciothermic reduction of Ti and Al oxides at 900 ° to 1000°C, Ca(OH)2 was removed by leaching with HC1 or acetic acid for the c o m p o u n d s . C o n c e n t r a t i o n of r e s i d u a l oxides in the powders are stated.
P R O C E S S I N G OF U L T R A F I N E P O W D E R S BY E L E C T R O N BEAM EVAPORATION
ICl.Lawson, D2.Stephenson, (Cranfield Institute of Technology, Bedfordshire, England.) J. Materials Science, Letters, Vol 10, No 12, 1991, 699-700. It is r e p o r t e d t h a t u l t r a f i n e m e t a l powders below 100 nm in size have been produced by a t h r e e - b e a m high p r e s s u r e electron beam technique in which there is a high degree of gas scattering. Variation in p a r t i c l e m o r p h o l o g y of Ni p o w d e r is described.
P R E S E N T STATE OF M A N U F A C T U R E OF A M O R P H O U S PM M A T E R I A L S
M.Miskovieova et al. (Ustave Exptl. Metal, 8AV, Kosice, Poland.) Pokroky Pra,skove Metalurgie, No 1-2, 1991, 34-49. (In Polish.) The production of a m o r p h o u s powder metallic materials is reviewed with respect to i m p r o v e m e n t s in p r o p e r t i e s w h i c h accrue from their use. Fre, Al, Ni, Ti, Nb and Si are considered for use in machinery, aerospace and electro-technical applications.
P R O G R E S S I V E T E C H N O L O G I E S IN POWDER M E T A L L U R G Y
M.Miskovicova et al. (Ustav exptl, Metal, SAV, Kosice, Poland.) Pokroky Praskove Metalurgie, No 1-2, 1991, 50-66. (In Polish.)
MPR June 1992 47