Activation energy for the reaction of nickel-carbon melts with alumina
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Table I. Analyses o f the Nickel Powder Mond Type 123, Specific Gravity 2.36
Activation Energy for the Reaction of Nickel-Carbon Melts with Alumina
Constituent
Pct Composition
Carbon Sulfur Iron Nickel
0.061 0.0003 0.005 99.93
B A L A J I V. P A T I L This communication contains the r e s u l t s on the reaction r a t e s and activation e n e r g y for the reaction: A120~(c) + 3 C ( / ) ~ 2 A l ( / ) + 3 C O ( g ) . T h e r e s u l t s w e r e o b t a i n e d by s t u d y i n g t h e c h a n g e i n t h e c a r b o n c o n t e n t s of n i c k e l - c a r b o n m e l t s c o n t a i n e d in a n a l u m i n a crucible at d e s i r e d t e m p e r a t u r e s . E x p e r i m e n t a l . T h e n i c k e l - c a r b o n m e l t was i n d u c t i v e l y h e a t e d u s i n g a s i n g l e p h a s e c o i l (7.5 c m ) p r e p a r e d f r o m 1.6 c m d i a m c o p p e r t u b e . I t c o n s i s t e d o f f o u r t e e n equally s p a c e d t u r n s . T h e m o d e l 7.5 K W 2 C T / L A r a t i o f r e q u e n c y g e n e r a t o r m a n u f a c t u r e d by M c D o w e l l E l e c t r o n i c s , M e t u c h e n , N.J. was used t o supply t h e p o w e r . A platinum-platinum-10 pet r h o d i u m thermoeouple was used t o m e a s u r e a n d c o n t r o l t h e m e l t t e m p e r a ture. T h e a l u m i n a e r u c i b I e w a s c y l i n d r i c a l i n s h a p e , 89 m m h e i g h t x 39 m m OD x 1.5 m m w a i l t h i c k n e s s a n d w a s s u p p l i e d by M o r g a n i t e R e f r a c t o r i e s , I n c . , D u n n , N o r t h Carolina. T h e crucible r e s t e d i n s i d e a p o r o u s a l u m i n a s h i e l d a t o p a east a l u m i n a s u p p o r t , w h i c h in turn r e s t e d on fiberfrax packing. T h e porous a l u m i n a s h i e l d was p r o v i d e d w i t h a b o r o n nitride c o v e r to m i n i m i z e r a d i a t i o n h e a t l o s s f r o m the m e l t . T h i s c o v e r was p r o v i d e d w i t h h o l e s to a c c o m m o d a t e a t h e r m o c o u p l e s h e a t h (5 m m I D x 8 m m O D ) , g a s i n l e t t u b e s a n d s a m p l i n g t u b e s . T h e e n t i r e crucible a s s e m b l y was s e a t e d i n s i d e a v y e o r t u b e , 75 m m O D × 1.5 m m t h i c k x 35 c m l o n g , w i t h a m e t a l b a s e p l a t e a n d w a t e r c o o l e d b r a s s top c o n t a i n i n g h o l e s c o r r e s p o n d i n g t o t h o s e i n t h e b o r o n n i t r i d e c o v e r . A f a s t f l o w of p u r i f i e d n i t r o g e n g a s (99.99 p e t p u r e : 3 p p m m a x i m u m m o i s t u r e ) a t 1200 m b m i n w a s m a i n t a i n e d o v e r t h e m e l t w i t h the h e l p of a v y e o r d i s p e r s i n g t u b e . T h e e n t i r e c r u c i b l e a s s e m b l y a n d the v y c o r e n c l o s u r e w e r e essentialIy at t h e atmospheric p r e s s u r e .~ T h e c a r b o n y l n i c k e l p o w d e r used in t h i s i n v e s t i g a t i o n w a s s u p p l i e d by A l e a n M e t a l P o w d e r s . E l i z a b e t h . N e w J e r s e y . T h e s p e
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