Viscosities of indium-lead liquid alloys
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A N D J. C. P E R R O N
The v i s c o s i t i e s of i n d i u m - l e a d a l l o y s have b e e n d e t e r m i n e d b y u s i n g the O s t w a l d ' t y p e v i s c o m e t e r . The v a l u e s have b e e n o b t a i n e d b y a r e l a t i v e technique s i n c e the v i s c o m e t e r h a s b e e n c a l i b r a t e d with Indium and l e a d . I s o t h e r m a l v i s c o s i t i e s show that the n e g a t i v e d e v i a t i o n s f r o m i d e a l m i x i n g d e c r e a s e with i n c r e a s e in t e m p e r a t u r e . The r e s u l t s a r e s t u d i e d f r o m the s t a n d - p o i n t of t h e r m o d y n a m i c s . The t e m p e r a t u r e d e p e n d e n c e can be d e s c r i b e d b y A r r h e n t u s r e l a t i o n . The a c t i v a t i o n e n e r g y d e p e n d s on c o n c e n t r a t i o n and is c l o s e to 1.6 k c a l / m o l e . In the s t u d i e d t e m p e r a t u r e r a n g e , it h a s b e e n e s t a b l i s h e d that the d a t a can be f i t t e d with A r r h e n t u s r e l a t i o n and A n d r a d e ' s equation. v i s c o s i t i e s of i n d i u m - l e a d a l l o y s w e r e d e t e r m i n e d in the t e m p e r a t u r e r a n g e 175 to 500~ We have used the c a p i l l a r y - f l o w m e t h o d ; the v t s c o m e t e r was a d a p t e d for u s e in a c l o s e d s y s t e m . This t e c h nique g i v e s the k i n e m a t i c v i s c o s i t i e s and the d y n a m i c v i s c o s i t i e s w e r e c a l c u l a t e d f r o m the d e n s i t y v a l u e s . * ' 2, s In a c a p i l l a r y - f l o w , the r e l a t i o n s h i p b e t w e e n the v i s c o s i t y and the e l a p s e d t i m e when a known v o l u m e of the liquid flows t h r o u g h a v e r t i c a l c a p i l l a r y tube, is given b y P o l s e u i l I e ' s equation. However m a n y c o r r e c t i o n t e r m s m u s t be t a k e n Into account. T h e r e f o r e , the v i s c o m e t e r was c a l i b r a t e d with liquids which have known v i s c o s i t i e s . So, the v i s c o s i t i e s of I n - P b a l l o y s w e r e determined by relative measurements.
s e a l e d up. The c o n t a c t s W,, Wa and Ws w e r e c o n n e c t e d to an e l e c t r i c t i m i n g c i r c u i t . The v i s c o m e t e r was put in a t u b u l a r f u r n a c e in such a way that the c a p i l l a r y
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I. E X P E R I M E N T A L METHOD The c a p i l l a r y - f l o w m e t h o d is t h a t in which the t i m e At t a k e n b y a v o l u m e V of the liquid to flow t h r o u g h a v e r t i c a l c a p i l l a r y tube under a p r e s s u r e d i f f e r e n c e A P i s m e a s u r e d . If A p is due to the m a s s of the liquid in the c a p i l l a r y tube and a s long a s l a m i n a r y flow ts c o n c e r n e d , k i n e m a t i c v i s c o s i t y v i s r e l a t e d to At through the equation. 4
v=AAt--
B
A--T
lcm
Reservoir
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w h e r e A and B a r e the v l s c o m e t e r c o n s t a n t s . T h e s e coefficients were obtained by calibration. The v i s c o m e t
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