Diffractometer measurements on a monolayer of filings: comparison with a thick specimen

An investigation of crystallite sizes in a cold-worked magnesium-indium alloy led to the use of diffractometer specimens composed of a monolayer of filings adhering to a thin film of vaseline on a glass slide. The characteristics of this type of specimen have been further investigated by comparison of diffractometer measurements on nickel filings in the form of monolayer and 1.5 mm thick specimens. Crystallite sizes obtained by Fourier analysis and lattice parameters are in good agreement. The diffraction line intensities are of similar magnitude at high angles but the monolayer specimen intensities decrease at low Bragg angles relative to those from the thick specimen. The effects of specimen transparency to X-rays on line breadths, peak positions and intensities are briefly discussed.