SUMMARY
The subject of the paper is an analysis of the role of the buffering and complexing compounds (BCC) applied in electroless Ni-P deposition baths, with two BCC additives. The process behaviour and the mechanism of action for the most important baths with two BCC additives are reviewed in the introduction part of the paper. The experimental part of paper presents the investigation of electroless Ni-P deposition from acidic (pH = 3 - 6) and alkaline baths (pH = 7,5 - 9,5), containing nickel sulphate and sodium hypophosphite, with added some BCC. Special attention was paid to citrate and glycine as main BCC. It was concluded that the Ni-P deposition rate was mainly influenced by citrate content or by pH in glycine-containing baths. Inorganic additives increased deposition rate in citrate baths. The deposited Ni-P coatings contained over 10% of P, glycine as BCC decreased this content up to 2%.
Keywords
Electroless deposition, Ni-P, beffers.
4 Politechnika Warszawska
5 Instytut Mechaniki Precyzyjnej, Warszawa
