Methods for preparing nickel plating solutions containing nickel(+2) 1-hydroxyethane-1,1-di-phosphonate complexes

The purpose of the work is to review the methods known from the literature and to propose the new methods for preparing the nickel electroplating and nickel electroless plating solutions containing nickel(+2) complexes with 1-hydroxyethane-1,1-diphosphonic acid CH 3 C(OH)(PO 3 H 2 )2 of various proton and stoichiometric composition which allow to obtain high quality nickel coatings. The classification of preparing methods on the basis of chemical reactions nature is given. The advantages and the limitations of each method are discussed. The starting materials are water soluble and water insoluble nickel(+2) salts, nickel(+2) 1-hydroxyethane-1,1-diphosphonates, 1-hydroxyethane-1,1-diphosphonic acid, sodium or potassium 1-hydroxyethane-1,1-diphosphonates. The conclusion is that the methods which base on the use of nickel(+2) bis(1-hydroxyethane-1,1-diphosphonate(1-)) tetrahydrate are the most versatile and convenient. The examples of the preparation of 1-hydroxyethane-1,1-diphosphonate solutions for nickel plating without other substances or with the second ligand (ammonia, ethylenediamine, triethanolamine and others) are given.