Abstract: A thermoelectric material which exhibits a high thermoelectric performance even at high temperatures is shown and described. A thermoelectric material is provided with a plurality of conductive layers made of a first semiconductor only and a plurality of barrier layers made of a second semiconductor only, which are alternatingly arranged, a diffusion-preventive layer being interposed between neighboring conductive layers and barrier layers. Diffusion between the conductive layers and the barrier layers under high-temperature conditions is prevented, and the thermoelectric material maintains high performance standards at high temperatures.

Abstract: A thermoelectric material having excellent thermoelectric performance is shown and described. A thermoelectric material is formed having a plurality of conductive layers and a plurality of barrier layers that are alternatingly formed one upon the other such that one conductive layer is sandwiched by two barrier layers. The conductive layers are composed of a first semiconductor only, and the two barrier layers located on the outermost sides of the material each have a main layer made of a second semiconductor only and a boundary layer made of the first and second semiconductors. A plurality of barrier layers positioned in between the conductive layers each have a main layer and two boundary layers provided on opposite sides of the main layer. The thickness t.sub.1 of the conductive layer and the thickness t.sub.2 of the barrier layer have a relationship of 2t.sub.1 .ltoreq.t.sub.2 .ltoreq.50t.sub.1.

Abstract: An engine part with a cast main body and a manifold type ceramic liner which is cast in the main body to define a manifold type exhaust passage therein, the ceramic liner including a hollow cylindrical liner body and a plurality of cylinder members branched from the liner body, a through portion being provided at a branched area of the ceramic liner for communicating inside and outside of the ceramic liner at which area adjacent cylinder members are branched apart, the through portion being filled with a molten metal at the time of casting the main body.