Abstract: A ceramic joining unit, ceramic heater and gas sensor, the ceramic joining unit including: a ceramic base member; an electrode pad provided on a surface of the ceramic base member; a coupling terminal; and a joining portion, wherein the electrode pad includes: a first layer in contact with the ceramic base member; and a second layer laminated on a surface of the first layer and in contact with the joining portion, wherein each of the first and second layers contains a ceramic material as a main component, a content of the ceramic material in the first layer is greater than that of the second layer, and a contour of the first layer is located outside of a contour of the second layer at an entire periphery of the first layer.

Abstract: A ceramic heater includes a core material and a ceramic sheet covering the core material, and wherein a side of the ceramic sheet opposite the core material is an outer side of the ceramic heater. A method for manufacturing the ceramic heater includes forming a through hole in a ceramic sheet which is diametrically enlarged from a first surface toward a second surface of the ceramic sheet, forming a via conductor, forming on the second surface a heating portion and lead portion for connecting the heating portion and the via conductor, and covering a core material with the ceramic sheet such that the first surface faces an outer side of the ceramic heater.

Abstract: A ceramic joining unit, ceramic heater and gas sensor, the ceramic joining unit including: a ceramic base member; an electrode pad provided on a surface of the ceramic base member; a coupling terminal; and a joining portion, wherein the electrode pad includes: a first layer in contact with the ceramic base member; and a second layer laminated on a surface of the first layer and in contact with the joining portion, wherein each of the first and second layers contains a ceramic material as a main component, a content of the ceramic material in the first layer is greater than that of the second layer, and a contour of the first layer is located outside of a contour of the second layer at an entire periphery of the first layer.

Abstract: A ceramic-metal assembly including: a ceramic base; an electrode pad provided on a surface of the ceramic base; a connection terminal for external electrical connection; and a joining portion which joins the connection terminal to the electrode pad. The electrode pad has a first layer which is in contact with the ceramic base and a second layer which is in contact with the joining portion. The first layer contains 20 to 50 vol % of a ceramic component, and the second layer contains a component of the joining portion.

Abstract: A ceramic heater and method for manufacturing the ceramic heater, the ceramic heater including a core material and a ceramic sheet covering the core material, and wherein a side of the ceramic sheet opposite the core material is an outer side of the ceramic heater, the method including forming a through hole in a ceramic sheet which is diametrically enlarged from a first surface toward a second surface of the ceramic sheet, forming a via conductor, forming on the second surface a heating portion and a lead portion for connecting the heating portion and the via conductor, and covering a core material with the ceramic sheet such that the first surface faces an outer side of the ceramic heater.

Abstract: A ceramic-metal assembly including: a ceramic base; an electrode pad provided on a surface of the ceramic base; a connection terminal for external electrical connection; and a joining portion which joins the connection terminal to the electrode pad. The electrode pad has a first layer which is in contact with the ceramic base and a second layer which is in contact with the joining portion. The first layer contains 20 to 50 vol % of a ceramic component, and the second layer contains a component of the joining portion.

Abstract: A ceramic heater has a structure in which a resistance heating element mainly composed of a metal having a high melting point is embedded in a ceramic substrate. With an average grain size for component grains of the ceramic substrate taken as dB and that for component grains of the resistance heating element taken as dH, a dH/dB ratio is adjusted to not greater than 0.8.