The influence of the solution composition including additives on the structure and composition of electrochemical Ni–B coatings

Abstract

The structure and internal stresses were investigated for d.c.‐plated Ni composite deposits prepared from a low‐concen‐tration Watts electrolyte, with and without additive agents and dispersive B particles. The dispersed phase and additives used in the bath were shown to affect the composition and structure of the electrodeposited composite layer. An increase in the content of B particles in the coating and in the size of [111] nickel crystallites led to increased roughness of Ni‐B coatings. The microhardness of the deposited Ni‐B layers increased as the size of [111] nickel crystallites decreased. The internal stresses of the deposited composite coatings depended to a large degree on the additive in the bath. Ni‐B coatings had a (100) texture, with texture (111) and (311) also frequently occurring. Orientation (100) developed even more strongly than in coatings deposited without additives. This shows that in the presence of 3‐(1‐pyridinio)‐propanesulfonate inner salt (PPS), the development of (110), (111) and (311) orientation is blocked. When the additives were used together, the dimensions of the [111] nickel crystallites in all coatings decreased to the smallest dimension in any of the studied coatings. The results suggest that as the effect of the organic compounds employed the nanostructure of the nickel matrix was developed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)