D Nickel D Zirconium oxide
Nickel layers with incorporated zirconia particles of 5 nm crystallite size with a thickness between 5 and 80 ΞΌm were deposited electrochemically on rolled steel substrates. An aqueous electrolyte solution containing nickel sulphate, nickel chloride, and boric acid (Watts bath) was used for the deposition process. The crystallite size distribution, the microstructure, and the texture of the samples were investigated by means of X-ray diffraction methods. The analysis of peak width data has shown that with increasing layer thickness the surface region of the layers which is penetrated by the radiation up to a depth of several ΞΌm exhibits a continuous growth in the crystallite size. Corresponding investigations by scanning electron microscopy of the cross-sections of the layers support this observation. Furthermore, the addition of zirconia particles results in a reduced crystallite size. Pole figure determinations of the nickel Bragg reflections (1 1 1), (2 0 0), and (3 1 1) revealed the presence of a fibre texture parallel to the [1 0 0] lattice direction. The prominence of the texture of the surface region rises with increasing layer thickness. The formation of the texture is strongly reduced by the co-deposition of the zirconia particles.