Sol-gel processing and automation of tunable ceramic materials

Sol gel processing of ceramic materials has attracted much interest in the past decade because of its inherent advantages in homogeneity of the resulting powder, fine grain size, high purity, and ability to mix disparate materials well. Sol gel processing is particularly apt to tunable electroceramics such as barium strontium titanate (BST) because of the fine grain size and purity desirable in such materials. It may be desirable to develop a semiautomatic system to produce the tunable ceramic powder, thin film and ceramic devices. Thin film tunable ceramics can be deposited on to a substrate with or without conductive traces by using a microwave plasma deposition system. In this paper, we have shown such a system incorporating microwave power for calcination, binder burn out and final sintering to a near net shape manufacturing of ceramic devices. This paper also describes the sol gel processing method for BST and compares properties of materials prepared by the sol gel method and the more conventional carbonate and oxide powder method.