Microfabrication of components based on functionally graded materials

Functionally graded materials (FGMs) are advanced innovative materials with gradual varying composition. They have been used for applications where the operating conditions are tuneable. However, there is limited research work invested to produce FGMs for microelectormechanical systems applications. This chapter discusses a process for the fabrication of FGM microceramic components. The process demonstrates a way to produce ceramic microcomponents with different materials at each side of a layer. The alumina/zirconia FGM has been developed to obtain microcomponents that combine properties of both alumina and zirconia. The development of multilayer FGMs has been achieved using highly stable alumina/zirconia suspensions with different compositions. Suspension stability was achieved by controlling both pH and the concentration of dispersant with respect to the powder weight. Problems of crack and cambers have been identified, discussed, and minimized by controlling the green and sintered conditions. The scanning electron microscopy and backscattered electrons show clearly a nearly net-shape alumina/zirconia microceramic component with a gradient composition.