Etude des profils de raies de diffraction des rayons X d'une poudre d'hydroxyde de nickel

The 001,100 and 102 X-ray diffraction lines from a powder sample of nickel hydroxide were measured and the data analysed using various measures of breadth. The specimen of Ni(OH)₂ was obtained from the hydrolysis of nickel hydroxide nitrate. Corrections for instrumental and spectral broadening are made by means of the Stokes and LWL methods and also using the variances of the diffraction profiles. The two deconvolution methods are compared and information about the size and shape of the particles is also obtained. From the 001 and 100 lines it is shown that the crystallites approximate to cylindrical plates that are roughly circular or hexagonal in section, with a diameter of 388 Å and a mean height of 66 Å. This result is confirmed by the good agreement between the observed apparent size for the 102 line and the value calculated using the above dimensions. Consideration of the taper parameter in the variance method indicates that the cross section is not uniform in a direction perpendicular to the cylinder axis and the c axis of the unit cell, such as would occur if the ends of the cylinder were not planar.