Selective laser sintering of barium titanate–polymer composite films

A selective laser sintering process has been used to consolidate electro-ceramic thin films on silicon substrates. Methods of forming pre-positioned layers of barium titanate were investigated by spin-coating the feedstock powder mixed with a commercial polymer photo-resist. The ceramic–polymer composite was deposited directly onto a nickel film which was evaporated onto a silicon substrate, pre-oxidised to form an electrically insulating layer. A range of laser processing parameters was identified in which consolidated barium titanate layers could be formed. The laser power was found to be more influential in forming sintered microstructures than laser exposure time. The microstructure of barium titanate films is sensitive to the SLS laser-processing conditions, with the optimum laser powers for the processing of the BaTiO₃–polymer found to be in the range 17–20 W. This article highlights the possibility of using ‘direct write’ techniques to produce piezoelectric materials upon silicon substrates.     

Selective laser melting of high aspect ratio 3D nickel–titanium structures two way trained for MEMS applications

Selective laser melting has been used to build high aspect ratio, three-dimensional NiTi micro-electro-mechanical components. Cantilever beams manufactured in this way have been two-way trained and actuated by ohmic heating demonstrating the suitability of the process for applications in micro-electromechanical technologies. The influence of laser dwell time and raster pitch on the density of NiTi shape memory alloy parts and the resolvable feature sizes achievable are discussed. The shape memory effect properties of solid parts produced by selective laser melting are also reported in contrast to those properties exhibited by NiTi alloys resulting from other processes.