Theoretical calculation of the solubility of hydrogen in liquid metals
- PDF / 521,363 Bytes
- 5 Pages / 612 x 792 pts (letter) Page_size
- 33 Downloads / 264 Views
The solubility of hydrogen in liquid pure Fe, Co, Ni, and Cu is calculated in terms of a hard sphere version (the scaled particle theory) of the Percus-Yevick equation for the liquid state. The hard sphere radius of a metal atom is estimated from the packing density for the liquid structure factor which has been reported to fit satisfactory with the observed diffraction data for the liquid metals. For a hydrogen atom dissolved in the metals, the hard sphere radius is derived as a function of the screening distance. Good agreement is obtained between theoreticallyCalculated Sieverts' constants for the metals and experimental observations. A n u m b e r of p r e c i s e l a b o r a t o r y d e t e r m i n a t i o n s of the s o l u b i l i t y of h y d r o g e n in i r o n , cobalt, nickel, and t h e i r alloy m e l t s have a l r e a d y b e e n c a r r i e d out, and r e l i a b l e v a l u e s for the s t a n d a r d f r e e e n e r g y of h y d r o g e n s o l u tion have b e e n e s t a b l i s h e d , x-s T h e o r e t i c a l i n t e r p r e t a t i o n of gas s o l u b i l i t y is l i m i t e d b e c a u s e of u n c e r t a i n t i e s r e g a r d i n g m o l e c u l a r and e l e c t r o n i c s t r u c t u r e s of m o l t e n m e t a l s . Saito 4 has a p p r o a c h e d the s u b j e c t in t e r m s of q u a s i c h e m i c a l a p p r o x i m a t i o n s , and has p r e s e n t e d a n e x p l a n a t i o n of the p h y s ical s i g n i f i c a n c e of the i n t e r a c t i o n p a r a m e t e r of h y d r o gen d i s s o l v e d in i r o n alloy m e l t s . Although this is a n i n t e r e s t i n g approach which m a y be a p p r o p r i a t e to p r e dict the effect of alloying e l e m e n t s on the s o l u b i l i t y of h y d r o g e n , it m u s t be noted that the p a r a m e t e r (a p r o d uct of a p a i r i n t e r a c t i o n e n e r g y and the n u m b e r of n e a r est n e i g h b o r a t o m s ) c h a r a c t e r i s t i c in the t h e o r y was d e t e r m i n e d e m p i r i c a l l y by u s i n g e x p e r i m e n t a l l y d e t e r m i n e d f r e e e n e r g y changes for the s o l u t i o n of h y d r o g e n in a p u r e i r o n m e l t . The a i m of the p r e s e n t s t u d y is to c o n s i d e r h y d r o g e n liquid m e t a l solutions to be m i x t u r e s of n e u t r a l p s e u d o a t o m s 5 c o m p o s e d of s c r e e n e d p r o t o n s and s c r e e n e d m e t a l i o n s , and to p r e d i c t the s o l u b i l i t y of hydrogen in the m e l t s in t e r m s of the s c a l e d p a r t i c l e t h e o r y e'7 which has b e e n shown to be e q u i v a l e n t to a h a r d s p h e r e v e r sion of the P e r c u s - Y e v i c k equation for the liquid state.a' s
THEORETICAL CONSIDERATION The C h e m i c a l P o t e n t i a l of H y d r o g e n in a Liquid Metal If it is p o s s i b l e to a s s i g n in s o m e context a s p h e r i c a l d e s c r i p t i o n to the h y d r o g e n a t o m in a liquid m e t a l , s o lution of a h y d r o g e n atom in the
Data Loading...
