A honeycomb structure according to at least one embodiment of the present invention includes: partition walls defining cells each extending from a first end surface of the honeycomb structure to a second end surface thereof to form a fluid flow path; and an outer peripheral wall. The partition walls and the outer peripheral wall are each formed of ceramics containing silicon carbide and silicon. A surface of the silicon has formed thereon an oxide film having a thickness of from 0.1 μm to 5.0 μm.

Set forth herein are processes and materials for making ceramic thin films by casting ceramic source powders and precursor reactants, binders, and functional additives into unsintered thin films and subsequently sintering the thin films under controlled atmospheres and on specific substrates.

A dielectric material includes a perovskite as a main phase, an A site of the perovskite including at least Ba, a B site of the perovskite including at least Ti, and Eu having +2 valence and +3 valence. A ratio of +2 valence of Eu is 21% or more.

In order to provide a dielectric composition having high relative permittivity at a wide range of temperatures, the main component of a dielectric composition includes strontium and tantalum.

A dielectric composition includes a main-phase particle and segregation particles. The main-phase particle includes a main component having a perovskite crystal structure represented by a general formula of ABO.sub.3. The dielectric composition includes RA, RB, M, and Si. Each of A, B, RA, RB, and M is one or more elements selected from a specific element group. Each of an RA content C.sub.RA to the main component, an RB content C.sub.RB to the main component, an M content to the main component, and a Si content to the main component is within a predetermined range. 0.50<(α/β)/(C.sub.RA/C.sub.RB)≤1.00 is satisfied, where a is an average RA content (mol %) and f3 is an average RB content (mol %) of specific segregation particles mainly including RA, RB, Si, Ba, and Ti in the segregation particles.

A dielectric composition includes main-phase particles each including a main component having a perovskite crystal structure represented by a general formula of ABO.sub.3. At least a part of the main-phase particles has a core-shell structure. The dielectric composition includes RA, RB, M, and Si. Each of A, B, RA, RB, and M is one or more elements selected from a specific element group. S.sub.RA/S.sub.RB>C.sub.RA/C.sub.RB is satisfied, where C.sub.RA is an RA content (mol %) to the main component in terms of RA.sub.2O.sub.3, and C.sub.RB is an RB content (mol %) to the main component in terms of RB.sub.2O.sub.3, in the dielectric composition, and S.sub.RA is an average RA content (mol %), and S.sub.RB is an average RB content (mol %), in a shell part of the core-shell structure.

A dielectric composition includes a main phase and segregation phases each including RE (at least one rare earth element). The main phase includes a main component having a perovskite crystal structure of ABO.sub.3 (A is one or more selected from Ba, Sr, and Ca, and B is one or more selected from Ti, Zr, and Hf). The segregation phases are classified into first segregation phases whose atomic ratio of Si to RE is 0 or more and 0.20 or less and second segregation phases whose atomic ratio of Si to the RE is more than 0.20. 0≤S1/S2≤0.10 is satisfied on a cross section of the dielectric composition, where S1 is an area ratio of the first segregation phases, and S2 is an area ratio of the second segregation phases. An atomic ratio of Si to RE in the second segregation phases is 0.80 or less on average.

A dielectric composition includes a main phase, first segregation phases, and second segregation phases. The main phase includes a main component having a perovskite crystal structure of ABO.sub.3 (A is one or more selected from Ba, Sr, and Ca, and B is one or more selected from Ti, Zr, and Hf). The first segregation phases include RE (one or more selected from rare earth elements), A, Si, Ti, and O. The second segregation phases include RE, A, Ti, and O and do not substantially include Si. 0.10<S2/S1≤1.50 is satisfied on a cross section of the dielectric composition, where S1 is an area ratio of the first segregation phases, and S2 is an area ratio of the second segregation phases.

A dielectric ceramic composition and a multilayer ceramic capacitor including the same are provided. The dielectric ceramic composition includes a BaTiO.sub.3-based base material main ingredient and an accessory ingredient, where the accessory ingredient includes dysprosium (Dy) and niobium (Nb) as first accessory ingredients. A total content of the Dy and Nb is greater than 0.2 mol and less than or equal to 1.5 mol based on 100 mol of titanium (Ti) of the base material main ingredient.

A dielectric ceramic composition and a multilayer ceramic capacitor comprising the same are provided. The dielectric ceramic composition includes a BaTiO.sub.3-based base material main ingredient and an accessory ingredient, where the accessory ingredient includes dysprosium (Dy) and cerium (Ce) as first accessory ingredients. A total content of Dy and Ce is greater than 0.25 mol % and equal to or less than 1.0 mol % based on 100 mol % of the base material main ingredient.