Microfabrication of components based on functionally graded materials

Functionally graded materials (FGMs) are advanced innovative materials with gradually varying compositions. They have been used for applications where the operating conditions are tunable. However, there is limited research work invested to produce FGMs for microelectromechanical 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 on each side of a layer. The alumina/zirconia FGM has been developed to obtain microcomponents that combine the 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 concerning 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 gradient composition.