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Unformatted text preview: ing the Dupont sample press. Samples weighing between 10 m g . and 40 m g . were sealed in the sample
pans. Weights of pristine T i S 2 p owder approximately equal to the weights of the sample were sealed in identical sample
pans and used as reference materials for the thermal
analysis. T h e samples and reference material were weighed and hermetically sealed in aluminum pans in order t o prevent
contamination. Pure T i S 2 w as used for the reference material i n order to maximize the sensitivity of the measurements to
the effects due to the silver intercalated in the sample.
T h e DSC program used for investigating the order-disorder
transition of the silver in the
A ppendix I Ag x TiS 2 i s outlined in P a g e - 495.2 S pecific Heat Measurements of Pure T i S 2 T h e stock T iS2 p owder w as used a s a sample material with
an empty sample pan and lid used as the reference in a search
for any possible transitions in t he T i S 2 i tself. D a t a were t aken over the temperature range o f 1 00 K t o 5 00 K . T h e only obvious reproclucib.le t ransition o ccurred a t 4 4 9 2 2 K d uring
the heating phase and 4 4 2 f 2 K d uring the cooling phase.
T h e hysteresis in the transition temperature between the
heating and cooling runs indicate that the transition may be
first order in nature. Todd and C oughlin (66) f ound a much broader transition involving no isothermal heat absorption
but a m aximum in the heat capacity near 4 2 0 K w ith t h e peak
slowly decreasing to z e r o in the range 4 70 5 20 K , - i ndicating that the transition is second order in n a t u r e .
X-ray patterns were taken of the pure T i S 2 s amples at 3 00 K , 4 5 0 K , a nd 5 50 K i n order to determine if any structural changes w e r e associated with the transition
observed in the thermal analysis of the T i S 2 A nalysis of
' the D ebye S cherrer X-ray data of the pure T i S 2 p owders at the latter temperatures ( 3 0 0 K , 4 50 K , a nd 5 50 K ) r evealed no
significant changes in the T i S 2 s tructure other than the expected small expansion of the lattice parameters at the
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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.
- Fall '09