Dresden 2003 – wissenschaftliches Programm
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M: Metallphysik
M 27: Nanoskalige Materialien II
M 27.1: Vortrag
Dienstag, 25. März 2003, 16:30–16:45, IFW D
NANOPARTICLE-STRENGTHENED Ni FILMS PREPARED BY DC AND PULSED DC ELECTROPLATING — •Hans Ferkel1, Jean-Frederic Castagnet1, and Ralf Anselmann2 — 1Institut für Werkstoffkunde und Werkstofftechnik, TU Clausthal, Agricolastr. 6, 38678 Clausthal-Zellerfeld — 2Merck KGrR, Abteilung NB-SC, Frankfurterstr. 250, 64293 Darmstadt
Nickel coatings strengthened by SiO2-nanoparticles were produced by co-deposition of nickel and SiO2-nanoparticles from electrolytic baths. The SiO2-nanoparticles with a median particle diameter of 10 and 25 nm, respectively, and a very narrow particle size distribution were dispersed in the employed nickel sulfamate bath prior electroplating at direct current (DC) or pulsed DC conditions. The hardness of the nickel film was drastically increased by the incorporated nanoparticles even when only volume fractions less than 5 % were co-deposited. The hardness was increased from 200 HV for pure nickel to up to 550 HV for the reinforced films. Transmission electron microscopy reveals that the nanoparticles are homogeneously distributed in the metal coatings, which is an requirement in order to gain the maximal effect from dispersion hardening. Pure nickel coatings produced under pulsed DC conditions exhibit increasing hardness with decreasing pulse length as expected. However the reinforced materials plated under PDC conditions show decreasing hardness with decreasing pulse length, but all these films are still harder than the pure nickel films produced under the same conditions without nanopowder addition. The results are discussed.