|
Electroless nickel is a broad term that incorporates a diverse mix of technology ranging from nickel boron and ternary alloys to highly functional composites. Nickel phosphorus deposits find the most use in the markets the plating industry serves. ==Technology overview== Electroless nickel (EN) deposits are typically classified as functional coatings and historically have found use in applications that require protection from either corrosion or wear and in some cases, both. Because of the unique deposit properties and uniformity of the resultant film, many other applications have emerged that continue to capitalize on the chameleon-like nature of electroless nickel. The majority of EN films used commercially are deposited from solutions formulated with sodium hypophosphite as the reducing agent.〔(Electroless Nickel Plating - A Guide )〕 This results in nickel films that are alloyed with phosphorus in ranges between 1 and 12 weight percent. The mechanical properties of NiP (ENP) deposits can be further enhanced not only by the co-deposition of inert particles such as teflon, silicon carbide or boron nitride but also by alloying with a third element, forming a ternary alloy of NiPX, where X can be copper, tungsten, molybdenum or tin depending on the particular formulation. Electroless nickel boron (NiB) alloys are also well cited in the literature,〔http://www.thomasnet.com/southern-california/plating-electroless-nickel-boron-nitride-95923496-1.html〕 although they are less commercially viable than the NiP alloys. The films are generated using either sodium borohydride or dimethylaminoborane as the reducing agent and can range in boron content from 1–5 weight percent. NiB films are typically used in the electronics industry where low-resistivity coatings are required and also find use in industrial applications when extreme wear and increased coating hardness is specified. Electroless nickel is no different than its electroplated counterparts in that it is only as strong as the weakest link in the process cycle. More clearly stated, successful electroless nickel plating requires both strict adherence to bath operating guidelines and optimal surface preparation. A well formulated electroless nickel process will not overcome improper surface preparation. Conversely, applying the wrong electroless nickel will short-circuit success even when the substrate is wonderfully prepared. The following links are critical: *Proper surface preparation *Choice of electroless nickel *Conformance to operating guidelines. Failing to recognize the interconnection between these three basic items will ultimately lead to failure of the plating, hopefully before the component reaches the field. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Electroless nickel」の詳細全文を読む スポンサード リンク
|