Measurements between 1 50 t o 1 80 k i n the heating

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Unformatted text preview: l i b r a t i o n c o e f f i c i e n t ( E). M ercury and indium s a m p l e s w e r e weighed and h e r m e t i c a l l y sealed in a luminum s a m p l e pans. A n e m p t y s a m p l e pan + l id w e r e used a s t he r e f e r e n c e material for e a c h s c a n . A strip chart r e c o r d e r w a s used t o r e c o r d t h e transition a s a f u n c t i o n of time. N eating/cooling r a t e s of 1 , 2 , 5 a nd 10 K /min w ere used. T h e a r e a of t h e t r a n s i t i o n peak w a s determined by tracing the t r a n s i t i o n peak w i t h a n e l e c t r o n i c pen and digitizing tablet coupled to an Apple IIE computer. T h e cell c a l i b r a t i o n c o e f f i c i e n t ( E) w a s c a l c u l a t e d u s i n g the equation: where: E = c ell c a l i b r a t i o n c o e f f i c i e n t H = h eat of f u s i o n of the s a m p l e m = m ass of t he s a m p l e A = p eak a r e a B = t i m e base s e t t i n g Y = y-axis range setting T h e a v e r a g e v a l u e o f t h e cell c a l i b r a t i o n c o e f f i c i e n t w a s Page - 4 7 - f ound to be 0 . 1 4 4 5 0 . 0 0 8 m W/mV b y a v e r a g i n g the values calculated from heating and c o o l i n g s c a n s of the mercury and indium samples u s i n g e q u a t i o n 4 - 1 2 . T h e value for the cell calibration coefficient a s determined from the heat of fusion of mercury and indium a g r e e s with t h e coefficient determined using the sapphire s t a n d a r d . T h e value of the cell coefficient ( E ) u sed in all subsequent c a l c u l a t i o n s in this thesis is E = 0.147: 0.002 mW/mV. Page - 4 8 - C HAPTER 5 I )SC R ESULTS 5 --1 D SC Procedure T i S p owder x 2 to 0 . 5 ) . L inear heating rates of 5 , 1 0 and Multiple D S C scans were taken o n a ll s amples ( x = 0 Ag 20 K /min w ere used during the heating phase of the scan and rates of 5 a nd 10 K /min w ere used during the cooling phase of the D S C s c a n s . Cooling rates greater that 10 K / m i n w e r e not obtainable due to the cooling efficiency of the apparatus. T h e powdered A g T i S s amples were placed in small aluminum 2 x s ample pans having a volume of about 0 .06 c c . and sealed with an aluminum lid us...
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This note was uploaded on 10/08/2009 for the course CME MAT E 630 taught by Professor Dr. during the Fall '09 term at University of Alberta.

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