Electronic component
A ceramic electronic component including a ceramic element assembly, an external electrode, and an underlying layer. In this ceramic electronic component, the underlying layer is formed on the ceramic element assembly, the external electrode is formed on the underlying layer, the underlying layer is formed of a metal material and a glass material containing a silicon atom, and the metal material exists in a highly dispersed state in the glass material.
1. A ceramic electronic component comprising:
a ceramic element assembly;
an underlying layer on the ceramic element assembly; and
an external electrode on the underlying layer, wherein
the underlying layer comprises a metal material and a glass material containing silicon atoms,
the metal material exists in a highly dispersed state in the glass material,
the metal material is granular in the underlying layer,
an average grain size of the metal material is not less than 2.0 nm and not more than 1.0 μm, and
an average inter-grain distance of the metal material is not less than 1.0 nm and not more than 1.0 μm.
2. The ceramic electronic component according to claim 1 , wherein the metal material contains at least one of copper and silver.
3. The ceramic electronic component according to claim 1 , wherein metal atoms of the metal material and the silicon atoms of the glass material coexist in a region of the underlying layer located at a center in a thickness direction of the underlying layer in a cross section in the thickness direction thereof, and
the region of the underlying layer has a depth of not less than 0.2 μm and not more than 2 μm from a surface of the cross section and a diameter of not less than 0.2 μm and not more than 2 μm.
4. The ceramic electronic component according to claim 3 , wherein a ratio of a content of the metal atoms to a content of the silicon atoms in the region is not less than 1.0 and not more than 200 in mass ratio.
5. The ceramic electronic component according to claim 1 , wherein a thickness of the underlying layer is not more than 10.0 μm.
6. The ceramic electronic component according to claim 1 , wherein the underlying layer is obtained by applying a sol in which a silicon compound, a metal salt, and one of boric acid and boron alkoxide are dissolved or dispersed in a solvent, and then applying heat treatment to the sol.
7. The ceramic electronic component according to claim 6 , wherein the heat treatment is performed under a reducing atmosphere.