Electrical applications of titanium-based FGMs manufactured by progressive lamination

It is well known that titanium materials can be used as photocatalysers for the adsorption of nitrogen oxides (NOx). In Osaka, such materials are already being tested on the surfaces of pavements and building walls. They are also used in anti-bacteria tiles in operating theatres. In the field of electrical engineering, too, the high relative permittivity of titanium allows these materials to play an important role in two areas: firstly as field relaxation agents, and secondly as high-voltage insulators to enhance the performance capacity of machinery. To meet the strenuous demands that these electrical uses place on the materials, two recourses are available to material designers: either the development of new materials, or the control of electrical fields within existing ones. The authors of this paper have attempted to manufacture a material permitting the control of field forces by taking advantage of properties of functionally graded materials (FGMs). The basic idea behind this is to guard against damage to machinery by bringing about relaxation in those parts where field forces are too high and increasing forces in parts where they are too low. The FGMs described in this paper are combined from titanium oxide and Korean kaolin. They allow a graded change in relative permittivity between the two surfaces. The paper compares the relative permittivities of these FGMs with those of 15 kinds of uniform material. There is a concluding discussion on the field relaxation effect.