Alumina sintered body
An alumina sintered body comprises an alumina substrate having a first main surface and a second main surface opposing each other, an embedded film electrode made of a metal and embedded in the alumina substrate at a depth H D of 0.4 mm or less from a first main surface SF 1 , and an embedded terminal formed of a metal, embedded in the alumina substrate nearer a second main surface SF 2 side than the embedded electrode. The embedded terminal is in contact with the embedded electrode and a film thickness H E of the embedded electrode is 25 μm or less.
1. An alumina sintered body comprising:
an alumina substrate having a first main surface and a second main surface opposing each other;
an embedded film electrode made of a metal and embedded in the alumina substrate at a depth of 0.4 mm or less from the first main surface; and
an embedded terminal formed of a metal, embedded in the alumina substrate nearer the second main surface side than the embedded electrode, the embedded terminal being positioned at the base of a hole having a diameter larger than the embedded terminal, an outer peripheral portion of the embedded terminal being chamfered or radiused at a contact surface at which the embedded terminal is in contact with the embedded electrode,
wherein a portion of the embedded electrode positioned on the contact surface between the embedded terminal and the embedded electrode is alloyed with the embedded terminal by integrally sintering the embedded terminal and electrode, and
wherein a film thickness of the embedded electrode is 25 μm or less.
2. The alumina sintered body according to claim 1 , wherein a radius of curvature of the outer peripheral portion chamfered is 0.2 mm or more.
3. The alumina sintered body according to claim 1 , wherein the embedded electrode is formed of at least one metal having a high-melting point, alloys thereof, or compounds thereof.
4. The alumina sintered body according to claim 1 , wherein the embedded electrode is a flat plate printed electrode.
5. The alumina sintered body according to claim 1 , wherein the embedded terminal is formed of a high-melting point metal or a compound thereof having a thermal expansion coefficient, that differs from that of an alumina sintered body by 2 ×10 −6 or less.
6. The alumina sintered body according to claim 1 , wherein the embedded terminal is formed of a metal containing at least one of platinum, niobium, and vanadium.