Elastic and Inelastic Properties of Electroplated Nickel Used in LIGA Techniques

摘要

The aim of this paper is a wide investigation at the micro scale of the elastic and inelastic properties of electroplated Nickel, which is extensively used in the LIGA techniques. Using a nano-indentation set-up, we have obtained the Berkovitch's hardness HB and the Young's modulus E. These mechanical properties are affected by the current densities used during the electroplating as well as the nature of the substrates. The roughness R_a was obtained thanks to confocal microscopy and a linear behavior of H_B versus l/(R_a)~(1/2) corresponds to a Hall and Petch relation. The yield stress Y_0 and the ultimate strength Q have been deduced from the experimental measurements using a Finite Element Method (FEM) .Q has been found sensitive to the deposition conditions. Moreover (Y_0+Q) has shown a linear dependence versus the hardness HB. Finally, Nickel microbeams fabricated by LIGA technique have been characterized with a bending test. The data deduced from this method, i.e. E and Y_0+Q, are in good agreement with the results obtained by nano-indentation.