Nanocrystalline metals and process of producing the same
AssigneeQueen'University at Kingston
InventorsUwe Erb, Abdelmounam M. El-Sherik
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Abstract
A process for producing nanocrystalline materials, and in particular nanocrystalline nickel having an average grain size of less than about 11 nanometers is described. The nanocrystalline material is electrodeposited onto the cathode in an aqueous acidic electrolytic cell by application of a pulsed D.C. current. The cell electrolyte also contains a stress reliever, such as saccharin, which helps to control the grain size. The novel product of the invention find utility as wear resistant coatings, hydrogen storage materials, magnetic materials and as catalysts for hydrogen evolution.
Claims17
A process for electrodepositing a selected metallic material in nanocrystalline form on a substrate comprising:
- (a) providing an electrolytic cell having an anode and cathode;
- (b) introducing an aqueous, acidic electrolyte containing ions of said selected metallic material into said electrolytic cell;
- (c) maintaining said electrolyte at a temperature in the range between about 55.degree. and about 75.degree. C.;
- and
- (d) passing a D.C. current, having a peak current density in the range between about 1.0 and about 3.0 A/cm.sup.2, at pulsed intervals during which said current passes for a time period in the range of about 1.0 to about 5 milliseconds and does not pass for a time period in the range of about 30 to about 50 milliseconds, between said anode and said cathode so as to deposit said selected metallic material in nanocrystalline form on said cathode.
A nanocrystalline metallic material having an average grain size less than 5 nanometers having a hardness which is at a maximum in a size range of 8-10 nm, and saturation magnetization properties substantially equal to those of said metallic in normal crystalline form.
Dependencies are inferred from the claim text.