Plasticity Length Scale in LIGA Nickel MEMS Structures

Abstract

The plasticity length scale parameters associated with rotational and stretch gradients in LIGA nickel MEMS structures plated from sulfamate bath are presented in this paper. These are obtained from micro-bend and micro-tensile experiments on LIGA nickel films with different thicknesses. The composite length-scale parameter, l c is measured to be ~ 4.8 µm for as-plated films (25, 50, 100 and 175 µm thick). The implications of the results are then discussed for the modeling of plasticity in LIGA nickel structures.

Role of oxide thickening in fatigue crack initiation in LIGA nickel MEMS thin films

“…5a. The results are consistent with prior work by Cho et al [9], Allameh et al [11], and Lou et al [17]. These show the usual dependence of fatigue life on stress, with the fatigue life decreasing with increasing stress amplitude.…”

“…Brown et al [10] also used comb-drive MEMS structures to show the susceptibility of Ni MEMS structures to fatigue. Subsequent work by Allameh et al [11], Boyce et al [12] and Yang et al [13][14][15][16] provided new insights into fatigue and fracture modes under monotonic and cyclic loading, while Lou et al [17] provided some measurements of plasticity length scales.…”

Focused Ion Beam System—a Multifunctional Tool for Nanotechnology

“…Using the ion beam is advantageous for obtaining images that illustrate high grain boundary definition, as compared to the electron beam which gives crisp resolute surface images. This feature of ion beam images can be observed in work done on modeling the plasticity in LIGA nickel MEMS structures (figure 28) [45]. Though there have been marked advancements in FIB imaging such as adding oxides or carbides for enhancement, one must be aware that using the focused ion beam to image a surface will damage the surface to some extent.…”

Development Of Microtesting Systems: I. Tensile Testing Of Metallic Microsamples

“…strength, fracture strength, fatigue and creep. Detailed results of stress-strain curves, fracture surface analysis, electron microscopy of LIGA Ni samples tested by microtensile testers are discussed elsewhere [7][8][9][10] . Table1.…”