Fabrication of Near Net Shape Alumina Nickel Composite Micro Parts using Aqueous Suspension

Ultra thick alumina-nickel composite micro parts were successfully fabricated using a combination of micromoulding soft lithography and colloidal powder processing of Al₂O₃-Ni suspension. The softlithographic method involves a deep UV lithography of SU-8, followed by the replication of Polydimethylsiloxane (PDMS), shaping the green by filling PDMS moulds with the composite paste. Next, drying, demoulding and finally sintering using TiO₂ as a sintering aid. The rheological properties have been characterized for the preparation of dispersed slurry. The optimal parameters have been achieved at pH=2; concentration of dispersant= 0.004 g/ml; solid loading= 65 wt%. After sintering, dense and free standing Al₂O₃-Ni composite micro parts have been achieved. Well dispersed nickel particles are found in the composite components. This approach provides a useful way to produce MEMS ceramic composites with tuneable properties by changing the amount of nickel in the matrix.