A ceramic tool material, in particular with piezoelectric effect and a preparation method thereof, and a cutting tool. The ceramic tool material includes the following raw materials by weight: 30-70 parts of matrix material, 30-70 parts of piezoelectric material, 5-10 parts of binder, and 10-20 parts of reinforcing phase and can be made into cutting tools. The cutting tool has a piezoelectric effect and excellent mechanical properties and can convert the cutting force signal into the charge signal during machining. By collecting charge signals, a cutting force can be measured and ceramic cutting tool condition can be monitored. Cutting force measurement function and high mechanical properties are integrated. A ceramic tool material with piezoelectric effect can measure the cutting force on the premise by meeting the cutting performance requirements.

A multilayer electronic component includes: a body including a plurality of dielectric layers and internal electrodes disposed to face each other with each of the plurality of dielectric layers interposed therebetween; and external electrodes connected to the internal electrodes and disposed on outer surfaces of the body, wherein each of the plurality of dielectric layers includes a BaTiO.sub.3-based base material main component and an accessory component including dysprosium (Dy) and terbium (Tb), a content of terbium (Tb) is 0.2 mol or more and less than 1.0 mol based on 100 mol of the base material main component, and the dielectric layer includes a plurality of dielectric crystal grains having a particle size of 60 nm or more and 250 nm or less at a point (D50) at which a cumulative volume is 50% in a cumulative particle size distribution according to a particle size distribution system.

A capacitor body includes a plurality of dielectric layers and a plurality of internal electrode layers stacked alternately. The plurality of dielectric layers include crystal grains of barium titanate, a rare earth element, and silicon. The crystal grains include a first crystal grain and a second crystal grain. The crystal grains each include a surface layer as a shell and an interior portion surrounded by the shell as a core. The first crystal grain has a higher concentration distribution of the rare earth element in the shell than in the core. The second crystal grain has distribution in which a ratio of a concentration of the silicon in the core and the shell is lower than a ratio of a concentration of the rare earth element in the core and the shell in the first crystal grain.

A composite fiber composed of at least a metal sintered body and a ceramic sintered body. In the composite fiber, the metal sintered body and the ceramic sintered body are adjacent to each other. The composite fiber having the metal sintered body and the ceramic sintered body can have a tensile strength of 5 kgf/mm.sup.2 or more.

A ceramic electronic component includes a multilayer chip having a substantially rectangular parallelepiped shape and including a first multilayer structure and a second multilayer structure disposed on each of top and bottom faces of the first multilayer structure, the first multilayer structure including first ceramic dielectric layers having a first width in a first direction in which side faces of the multilayer chip are opposite to each other, the second multilayer structure including second internal electrode layers having a second width less than the first width in the first direction, and a pair of external electrodes formed from the respective two edge faces to at least one of side faces of the multilayer chip, wherein main components of the first and second internal electrode layers differ from a main component of the external electrodes.

A dielectric composition and a multilayer capacitor including the same are disclosed. The dielectric composition including: a BaTiO.sub.3-based main ingredient; a first auxiliary ingredient including rare earth elements; and a second auxiliary ingredient including at least one of Ba and Ca but essentially including Ba, wherein the rare earth elements include Tb and Dy, and the first auxiliary ingredient and the second auxiliary ingredient satisfy a molar content condition of 0.40<(Tb/T_RE)*(Ba+Ca)<0.93, where T_RE is a total molar content of the rare earth elements in the first auxiliary ingredient.

A multilayer ceramic capacitor includes: a multilayer structure in which each of dielectric layers and each of internal electrode layers are stacked, wherein a relationship of 8.0≥I.sub.A/I.sub.B>1.40 is satisfied in a TSDC (Thermally Stimulated Depolarization Currents) of temperature elevation rate of 10 degrees C./min under a condition of 130 degrees C., 5 V/μm and a polarization of 30 min, when a peak current value on a lower temperature side in a temperature range of 130 degrees C. to 190 degrees C. is I.sub.A and a peak current value on a higher temperature side in a temperature range of 190 degrees C. to 280 degrees C. is I.sub.B.

A dielectric body includes a plurality of crystal grains of which a main component is barium titanate, and an additive including Zr, Eu and Mn. At least one of the plurality of crystal grains has a core-shell structure having a core and a shell. A Zr/Ti atomic concentration ratio is 0.02 or more and 0.10 or less. An Eu/Ti atomic concentration ratio is 0.001 or more and 0.03 or less. A Mn/Ti atomic concentration ratio is 0.005 or more and 0.05 or less. A total atomic concentration of the one or more rare elements is smaller than an atomic concentration of Eu when the dielectric body has the one or more rare earth elements. A median diameter of the plurality of crystal grains is 200 nm or more and 400 nm or less.

A dielectric composition includes a main ingredient having a perovskite structure represented by ABO.sub.3, where A is at least one of Ba, Sr, and Ca and B is at least one of Ti, Zr, and Hf, and a first accessory ingredient. The first accessory ingredient comprises 0.1 mole or more of a rare earth element, 0.02 mole or more of Nb, and 0.25 mole or more and 0.9 mole or less of Mg, a sum of contents of the rare earth element and Nb is 1.5 mole or less.

A multi-layer ceramic capacitor includes: a first region including a polycrystal including, as a main component, crystal grains free from intragranular pores; a second region that includes a polycrystal including, as a main component, crystal grains including intragranular pores and includes a higher content of silicon than a content of silicon in the first region; a capacitance forming unit including ceramic layers laminated along a first direction, and internal electrodes disposed between the ceramic layers; and a protective portion including a cover that covers the capacitance forming unit and constitutes a main surface facing in the first direction, a side margin constituting a side surface facing in a second direction orthogonal to the first direction, and a ridge constituting a connection portion, the connection portion connecting the main surface and the side surface to each other. The ceramic layers include the first region. The ridge includes the second region.