Soft magnetic materials for alternating current applications

PM IN ROAD T R A N S P O R T l).J. Mouht, (Ford Motor Co. Ltd, Basildon, I!K). The p a p e r trace(t the d e v e l o p m e n t of t h e use of I'M in t h e p r o d u c t i o n of a u t o m o t i v e paris. It w a s noted thai lhere are regional differences in usage. Nnrth American cars have about 10 kg of PM p a r t s a n d for Eurol)e a n d J a p a n the figures are 5.5 a n d 4 kg r e s p e c l i v e l y . PM l r a n s m i s s i o n c o m p o n e n t s d o m i n a t e in Ainerican cars but in J a p a n greater u s e is m a d e of PM li)r engine parts. PM p a r t s in use were listed. A t t e n t i o n was drawn to t h r e e factors of i m p o r t a n c e to t h e buyer of PM p a r t s for a u t o m o t i v e use, i.e. quality, lechnology a n d cost a n d t h e s e were discussed. POWDER M A T E R I A L S IN A E R O S P A C E G.W. M e e t h a m a n d I).R. Mayo, (British Aerosl)ace, Preston, UK). The requirements for aerospace m a t e r i a l s for c u r r e n t a n d f u t u r e use were d i s c u s s e d in t e r m s of I b m p r o p e r t i e s , stiffness, strength, lightness and the ability to w i t h s t a n d elevated t e m p e r a t u r e s . C o n s i d e r a t i o n w a s given to A1 alloys, notably ALLi alloys, Mg alh)ys a n d organic c o m p o s i t e s . T h e d e v e l o p m e n t of PM m a t e r i a l s with improved p r o p e r t i e s arising li'om t h e use of rapid solidification a n d m e c h a n i c a l alloying was outlined a n d alloys with novel c o m p o s i t i o n s were considered. The application o f PM m a t e r i a l s , particularly in gas turbines, was discussed. T R E N D S FOR PM C O M P O N E N T S IN AUTOMOTIVE A P P L I C A T I O N S G. T u r n e r a n d P.R. Mdis, ( J a g u a r Cars Ltd, Coventry, IRK). Possible f u t u r e d e v e l o p m e n t s in t h e application of PM p a r t s in a u t o m o t i v e u s e were d i s c u s s e d with reference to novel c o m p o s i t i o n s , control a n d utilization of p o r o s i t y for I u b r i c a t i o n p u r p o s e s a n d s i n t e r forging. PM C O M P O N E N T U S A G E IN TRANSPORTATION APPLICATIONS IN ITALY E. Mosca, (Assinter, Turin, Italy). The c o m p o n e n t s p r o d u c e d in Italy, by use of PM, for a u t o m o t i v e u s e were outlined and c o m m e n t s were m a d e c o n c e r n i n g q u a n t i t i e s produced. The use of PM to m a k e f u r t h e r c o m p o n e n t s was d i s c u s s e d w i t h r e g a r d to t o o l i n g a n d c o n t r o l of compaction.

P R O C E S S I N G OF S I N T E R E D S T A I N L E S S S T E E L PARTS P. Beiss, (Sintermetallwerk Krebs6ge, Radervormwald, G e r m a n y ) . The p r o c e s s i n g of s t a i n l e s s steel parts, with high density, m a d e from prealloyed powders, w a s discussed. C o n t a m i n a t i o n by N, from s i n t e r i n g a t m o s p h e r e s , w a s s h o w n to r e d u c e r e e o m p a c t i b i l i t y on d o u b l e pressing. The i m p o r t a n c e of r e d u c t i o n of Cr oxides, to a t t a i n high ductility, w a s e m p h a s i z e d . The use of t h e salt s p r a y t e s t to a s s e s s corrosion r e s i s t a n c e w a s discussed. It was showna thai an e n d u r a n c e of at least t e n clays e x p o s u r e w a s r e q u i r e d for a u t o m o t i v e use a n d t h a t m a n y s i n t e r e d g r a d e s do not m e e t this. An investigation into t h e effects of process p a r a m e t e r s on salt spray endurance was described. S a t i s i i m t o ~ results were r e p o r t e d to be o b t a i n e d by selection of c o m p o s i t i o n a n d d a t a c o n c e r n i n g t h e e f f e c t s of a l l o y e l e m e n t s were presented. STUDY OF PM P R O C E S S I N G OF T1 A N D M50 H S S F O R A E R O E N G I N E BEARING APPLICATION Y. Bienvenu et al, (Armines, Evry, France). A p r o g r e s s report on t h e d e v e l o p m e n t of PM T1 a n d M50 HSS for u s e as aero engine b e a r i n g s was p r e s e n t e d . The objective of t h e s t u d y was s t a t e d to be t h e o p t i m i z a t i o n of p r o c e s s i n g conditions. It w a s s h o w n t h a t for M50 a n d HIP at 1120°C a n d 100 MPa for 2 h o u r s leads to a fine carbide particle size (1 g m a n d grain size (5 to 35 }am). The T1 alloy could be v a c u u m s i n t e r e d to n e a r full density and further densified by c o n t a i n e r l e s s HIP or h o t work, c a r b i d e particle sizes 2 to 5 g m a n d grain size 20 to 30 Bm being observed. MIM P R O D U C T S IN T H E TRANSPORTATION INDUSTRY G.R. Loosemore a n d A. Hayward, (Royal O r d n a n c e Speciality Metals Ltd, Wolverh a m p t o n , UK). The MIM p r o c e s s w a s described with a n a t t e n t i o n being given to t h e i m p o r t a n c e of correct debinding. A p p l i c a t i o n s a n d t h e m a r k e t for MIM p a r t s were d i s c u s s e d a n d e x a m p l e s of MIM c o m p o n e n t s were given. E X P E R I E N C E WITH C E R A M I C S IN GAS T U R B I N E S G.W. M e e t h a m . The a p p l i c a t i o n of ceramic materials, with a n d w i t h o u t fibre or p a r t i c l e

r e i n f o r c e m e n t to high t e m p e r a t u r e g a s turbine components, was discussed. D e v e l o p m e n t work on t h e s e m a t e r i a l s w a s described. The lack of defect t o l e r a n c e was r e p o r t e d to be t h e m a i n faclor limiting t h e u s e of m o n o l i t h i c ceramics. It was predicted t h a t c e r a m i c fibre r e i n f o r c e d c e r a m i c s would find a p p l i c a t i o n s in gas turbines. COMPETITION BETWEEN FERRITE AND IRON-NEODYMIUM-BORON M A G N E T S FOR AUTOMOTIVE U S E B. S c h e l b a n d A. Nisch, ( B T M a g n e t Technologic, Herne, G e r m a n y ) . A c o m p a r i s o n w a s m a d e between ferrite materials and Fe-Nd-B for use as permanent magnets for automotive electric motor applicalions. The l i m i t a t i o n s to u s e of Fe-Nd-B m a g n e t s were r e p o r t e d to be high (:osl, low Curie t e m p e r a t u r e a n d poor corrosion properties. Motors c o n t a i n i n g t h e two types of m a g n e t were c o m p a r e d as to cost efficieneT, noise a n d design. It w a s c o n c l u d e d t h a t t h e ferrite m a t e r i a l would c o n t i n u e to be t h e preferred m a t e r i a l for m o s t a u t o m o t i v e applications. E x a m p l e s were given. SOFT M A G N E T I C M A T E R I A L S FOR A L T E R N A T I N G C U R R E N T APPLICATIONS P. J a n s s o n , (H6gan/is AB, tt6gan/is, Sure den). The use of PM to p r o d u c e magnetically soft Fe-based c o m p o n e n t s w a s d i s c u s s e d w i t h r e g a r d to t h e e f f e c t s of p r o c e s s variables on t h e properties. The ability of PM to m a k e c o m p o s i t i o n s , s u c h as Fe0.8%P, which are beyond t h e capability of e a s t / w r o u g h t m e t a l l u r g y lo p r o d u c e , is e m p h a s i z e d . The e f f e c t s of p r o c e s s variables on m a g n e t i c p r o p e r t i e s of Fe-SiP a n d Fe Sn P were p r e s e n t e d . E x a m p l e s d e m o n s t r a t i n g t h e a d v a n t a g e s of PM materials for solution of specific application or cost p r o b l e m s were given. POWDER M A T E R I A L S IN B A T T E R I E S A P P L I E D TO T R A N S P O R T APPLICATIONS R.A. Grace, (Salt Nife, t l a m p t o n , UK). The a p p l i c a t i o n s of PM m a t e r i a l s in p r i m a r y a n d r e c h a r g e a b l e b a t t e r i e s for use in t r a n s p o r t were reviewed with regard to t h e functions, i n t e r m i t t e n l or c o n t i n u o u s use, of t h e batteries. The use of PM in m a k i n g electrodes a n d eleelrode s t r u c t u r e s were described. High m a t e r i a l purity w a s said to be essential. Some electrode

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