The new method of double dil ution can be used to
a nalyse quantitatively all the phases of a multiphase system
wit hout the need to construct calibration curves, and with as few
as 2 or 3 mixtures prepa red for X-ray diffraction. A specific
weight of the powdered specimen which is to be analysed, is
mixed with a fixed proportion of internal standard. The standard
can be any crysta ll ine compou nd with a prefe rably symmetrical
StruclUre, not present in the original specimen. The other part to
be mixed is a combi nation of finely ground pure phases or
materials of known purity. Area under the diffracted peaks or
integra ted inte nsi ty h measured. At least twO X-ray samples of
known and different proportions shou ld be employed.
Intcnsily ratiO, Y axis, is plotted against weight ratio, X axis,
so that a linea r plol for combina tion of 2 peaks from each phase
and standard is plaited. Required phase is read from the
in tercept of the abscfssu. Mathematics of lilt:: m4!thod Is ctlscussc<1
with a n example of determining alumina, mullite. q uartz a nd
silicon in a ceramic test piece containing glassy phase