https://pureadmin.qub.ac.uk/ws/files/126683921/Edited_sudagar_R1.pdf

Electroless nickel, alloy, composite and nano coatings – A critical review

Light alloys are more and more widely used, notably in aeronautics and the car industry. To improve their superficial properties, they can be covered with a hard and wear resistant protective layer. In this article, we examine the possibility of depositing a thick autocatalytic electroless Ni–B plating on aluminium alloys. We propose an alkaline bath containing sodium borohydride as the reducing agent. The deposition rate is held constant by a regular replenishment of the Ni–B bath allowing a rate of about 25 μm/h. The Knoop microhardness of the Ni–B deposits after the bath reaches about 750 hk100. Appropriate heat treatment can increase the deposit microhardness up to more than 1000 hk100 but must be applied with regard to the substrate properties. The study of these heat treatments will be published in a further paper.

Autocatalytic electroless nickel-boron plating on light alloys

Electroless Ni–P coatings provide high hardness and excellent resistance to wear and abrasion The present work aims to study the formation of electroless Ni–P graded coatings, with varying nickel and phosphorus contents of the individual layers and to evaluate their corrosion resistance by polarization and electrochemical impedance spectroscopic studies The possibility of preparing electroless Ni–P graded coatings by sequential immersion in three different plating baths is discussed The study reveals that electroless Ni–P graded coatings offer better corrosion resistance than non-graded Ni–P coatings

Deposition of electroless Ni–P graded coatings and evaluation of their corrosion resistance

Vacuum heat treatment of electroless Ni–B coatings

A process for manufacturing an optical data storage disk stamper includes the steps of providing a chemically vapor-deposited, silicon carbide substrate having a toughness of about 4.5 MPaXm, a roughness of about 1 nm, and a flatness of about 6 νm and depositing a negative photoresist on a surface of the substrate. The substrate has a diameter greater than about 120 mm and a thickness greater than about one mm. The negative photoresist then is exposed with a laser to form a negative, data pattern in the photoresist. The photoresist is developed, and the ceramic substrate is ion machined to form the data pattern, in the substrate, such that a spiral track of ridges and lands is formed wherein each ridge has a height of about in a range of 20 to 200 nm. After the data pattern has been ion machined into the substrate, the developed photoresist is stripped from the substrate.

Process for manufacturing optical data storage disk stamper

/pdf/electroless-nickel-plating-3uioijeuka.pdf

Donald W. Baudrand

Papers

Electroless Nickel Plating