Brittle Fracture of Electrodeposited Gold Observed by Micro-Compression

Abstract

Micro-compression tests were conducted to evaluate micro-mechanical properties of electrodeposited gold. The gold lm was electrodeposited on a platinum substrate with a thickness of 40 μm. The gold lm was found to be composed of columnar textures along the lm growth direction. Two sizes (10 × 10 × 20 μm 3 and 20 × 20 × 40 μm 3 ) of micro-pillars with a square cross-section and the long-side parallel to the Pt/ Au interface were fabricated by focused ion beam. From the micro-compression tests, brittle fracture was observed. Both of the micro-pillars showed a high compressive strength of about 600 MPa, which are much higher than the strength of the bulk gold. Grain size of the gold lm was estimated to be 14.7 nm, which is believed to be the main factor giving the high compressive strength. The strength of the larger micro-pillar was slightly lower than that of the smaller micro-pillar. The results con rmed presence of the size effect in these specimens.

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“…The Au film was electroplated using a cyanide-based electrolyte (33). The Au film was electroplated on a Pt substrate.…”

“…For the micro-compression test, two Au micro-pillars were fabricated by focused ion beam (FIB, Hitachi: FB2100). Details of the electroplating and the FIB fabrication are reported in a previous study (33). Dimensions of the Au pillar were 10×10×20μm 3 with a square cross-section, and the long-side was either perpendicular (pillar 1, Fig.…”