Skip to main content

ELECTRODEPOSITED MULTI LAYERS OF TRANSITION (PRECIOUS) METALS

Objective


Co-Pt(P) natural multilayers of very high coercivity, both for thin films (>5kOe) and for thick coatings (2kOe), were obtained. These are the electrodeposited films of the highest coercivity ever obtained, and their application for magnetic layers of computer hard disks or for permanent micro-magnets was investigated, by realising sample disks and thick electrodeposited layers. Similar layers with high Pt content were investigated as layers to improve the hot corrosion resistance.
Co/Cu multilayers, with sublayer of nanometer thickness, were realised with the single and double bath technique, obtaining layers showing the giant magnetoresistive effect. The Co/Cu layers obtained with the single plating bath showed superior stability at high temperature (up to 350°C), minor coercivity and strong magnetoresistance sensitivity; they showed interesting possibilities for magnetic sensors and magnetic recording heads.
Ag/Cu multilayers of high resistivity change with temperature were obtained with the single plating bath technique, with possible application as thermal sensors. Au/Co multilayers were electrodeposited from a single bath, decreasing the internal stresses with additions improving the layering definition. Decreasing the sublayer thickness friction coefficient decreases and wear resistance increases.
Ni-P/Sn multilayers with very high wear and corrosion resistance, combining the high hardness of the Ni-P sublayer with the good lubricating properties of the Sn sublayer, were electrodeposited with the double bath technique. The maximum corrosion resistance is obtained when the Sn sublayer thickness is very small and passivation results from compounds obtained from the oxidized P and Sn.
The research will investigate the ElectroChemical Deposition (ECD) of compositionally modulated multilayers (CMM) of transition metals, containing precious metals. CMM of high coherency and layer thickness uniformity can be obtained by ECD; perfection depends on bath composition and deposition conditions.

Major research tasks are : (i) design and study of prototype equipments for ECD-CMM electrodeposition in a single bath, containing all the metals to be deposited, and in dual baths, with deposition of sublayers in the separate baths; (ii) electrodeposition and determination of the optimum conditions to obtain microlayered alloys, with precious metals as nanolayers; (iii) development of models for layers interaction and CMM electrocrystallization, in order to understand ECD-CMM structure, layer growth and to increase the layer perfection; (iv) determination of ECD-CMM structural, magnetic, optical, thermal, transport and mechanical properties, and of their wear and corrosion resistance; (v) evaluation of ECD-CMM potentiality for industrial application in the field of : magnetic recording, electronic devices, electric contacts, hot corrosion and erosion resistant coatings.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

POLYTECHNIC OF MILAN
Address
Piazza Leonardo Da Vinci 32
20133 Milano
Italy

Participants (3)

FACULDADE DE CIENCIAS - UNIV DO PORTO
Portugal
Address
Pra‡a Gomes Teixeira
4000 Porto
Forschungsinstitut für Edelmetalle und Metallchemie
Germany
Address
Katharinenstraße 17
73525 Schwäbisch Gmünd
KUL
Belgium
Address
De Croylaan 2
3001 Leuven