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We have shown that TiN, NbN and TiC electrodes prepared from metal or respective compound powders by a screen printing method work well as AMTEC electrode (26th IECEC). TiC electrode (Thickness:2-3μm, 800°C, 0.07Pa) shows the highest power density (0.40W/cm2) in our work. This is almost same power density of others' electrodes under same temperature. This shows that AMTEC electrode can be prepared by screen printing method from metal or ceramic powders. The maximum power densities of TiN, NbN and TiC depend markedly on the degree of vacuum of low temperature room of AMTEC. In the measurements of NbN electrode (thickness:2-3μm), the power density of AMTEC increased from 0.12W/cm2 (at 130Pa) to 0.27W/cm2 (at 0.037Pa) with improvement of vacuum. TiC electrode shows same tendency. This indicates that the transfers of sodium vapor through electrode give an effect on the power density.

Along with the effort to improve engines for exhaust gas emission reduction and high power performance, the increment of exhaust gas temperature emerged as a new problem causing inner surface oxidation and thermal deformation of exhaust manifolds particularly. Under such circumstance, a novel ceramic coating exhaust manifold has been developed. This coating is composed two layers. The inner layer is oxidation resistant layer of comparably compact structure having same thermal expansion coefficient as the cast iron substrate, and the outer one is thermal insulating layer of very porous structure. These two coating layers have therefore made it possible to withstand the crack and peeling off because of the thermal impact of high temperature exhaust gas and made it applicable to the complex figured inner surface. This newly development coating process shall convert a conventional ductile iron manifold to a superior heat resistant manifold by application of the ceramic coating.