From the sample perpendicular to the incident x rays

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Unformatted text preview: surements and plotted as a f unction of the mole fraction of silver ( x) a s determined from weight measurements (Fig. 11). The intensity ratio of S /Ti w as P age -23aF igure 1 1 V erification of the Ag/Ti r atio for group A ( quenched from 800 s amples C) ity using X-ray of t he s ilver L a ity of the titanium K a flourescence. Integrated p eak divided b y the ir1tctyratt:d p eak v ersus the mole fraction s ilver ( x ) in Ag TiS a s dctermintxi by w eighing. x 2 0 0.1 0.2 0.3 0 0.5 0 .4 .6 Mole Fraction of Silver P age - 24c alculated in order to determine the accuracy of the method (since the S /Ti r atio should remain constant for all samples). The accuracy of the latter method for determining the relative amount of a particular element was determined to be 5 15% f rom the S /Ti r atio. The XRF results agree (to within 15%) w ith the mole fraction of silver (X) determined by weighing for 0 < X < 0 . 5 , a nd provides verification of the ratio of Ag to T iS 2 i n the Ag T iS s amples. 2 x X RF Sample Verification 3 -1 ( b ) (GROUP B - q uenched from 1 000 C ) X -ray fluorescence (XRF) spectra were taken of the group B ( quenched from 1 000 C ) A g T iS p owder samples as a check of x 2 the ratio o f A g to T i S 2' T he samples were mounted on graphite blocks and an I SI-DS130 s canning electron microscope equiped with an Ortec E G+G E EDS I 1 X -ray energy detector and analysis system was used to analyze the composition of the A gxTiS2 p owders. The sample was bombarded by energetic electrons which excite the atoms contained within some volume of the sample material. The stock T iS 2 p owder was used as the reference with the S /Ti r atio assumed to be exactly 2 . 0 in order to calibrate the equipment. sulfur K a ( 2.308 K eV), s ilver L a The intensities of the ( 2 . 9 8 4 K eV) a nd titanium K a ( 4.510 K eV) l ines were measured using a 1 5 K eV e lectron beam to excite the sample and ratios of S /Ti a nd A g/Ti c alculated for each of the (group 8 ) A gxTiS2 s amples. The penetration P age - 25d epth of the beam was estimated to be 1 . 5 u m. f rom earlier determinations of...
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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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