Thermal stability of electrodeposited LIGA Ni-W alloys for high temperature MEMS applications
Document Type
Article
Publication Date
1-1-2008
Abstract
For thermally stable LIGA materials for high temperature MEMS applications LIGA Ni-W layers and micro testing samples with different compositions (15 and 5 at W) were electrodeposited. In order to investigate the thermal stability the Ni-W layers were annealed at different temperatures (300-700 degrees C) and for different durations (1, 4, 16 h). Their microstructure and micro-hardness were than analysed after annealing and compared with those of as-deposited states. The observed microstructures show, in comparison to pure LIGA nickel, a small grain growth and a relatively stable structure up to 700 degrees C. The micro-hardness values of the LIGA Ni-W layers are higher than those of the pure LIGA nickel. The micro-hardness measurements for high W-content show in addition a low decrease of the hardness values with increase of the annealing duration. Tensile tests were carried out for each composition (5 and 15 at). Ni-W shows higher strength (UTS) above 750 MPa and 1,000 MPa, respectively and lower ductility than pure nickel.
Keywords
Pure Nickel, Annealing Duration, Nickel Sulphate, High Tungsten Content, Tomographic Atom Probe
Divisions
fac_eng
Publication Title
Microsystem Technologies
Volume
14
Issue
9-11
Publisher
Springer Verlag (Germany)
Additional Information
Haj-Taieb, M. Haseeb, A. S. M. A. Caulfield, J. Bade, K. Aktaa, J. Hemker, K. J. 7th International Workshop on High-Aspect-Ratio Micro-Structure Technology Jun 07-09, 2007 Besancon, FRANCE