[en] Electroless nickel-boron coatings are prepared by the liquid phase reduction of nickel salts by a chemical agent without external current source, using a reactive such as sodium borohydride or dimethylamine borane.
The coatings already available on the market, present hardness (>850 hv) and wear characteristics comparable to those of hard chrome in the as deposited state and reach much higher hardness values (more than 11 hv) after heat treatment, while providing exceptional dimensional compliance.
Nevertheless, those coatings are not widely used because the available deposits contain small amounts of toxic heavy metals such as Pb and Tl. Recent developments have allowed to develop new bath formulation, exempt of toxic heavy metals, while keeping or improving the properties of the coating. This makes electroless nickel-boron coatings a strong alternative to hard chrome in several fields of applications.
Research center :
CRIM - Ingénierie des matériaux
Disciplines :
Materials science & engineering Chemistry Physics
Author, co-author :
Vitry, Véronique ; Université de Mons > Faculté Polytechnique > Service de Métallurgie
