A cutting tool (1) formed of a silicon nitride-based sintered body (2) including a matrix phase (3), a hard phase (4), and a grain boundary phase (10) in which a glass phase (11) and a crystal phase (12) exist. The sintered body (2) contains yttrium in an amount of 5.0 wt % to 15.0 wt % in terms of an oxide, and contains titanium nitride as the hard phase (4) in an amount of 5.0 wt % to 25.0 wt %. In an X-ray diffraction peak, a halo pattern appears at 2θ ranging from 25° to 35° in an internal region of the sintered body (2). A ratio B/A of a maximum peak intensity B to a maximum peak intensity A satisfies 0.11≤B/A≤0.40 . . . Expression (1) in a surface region of the sintered body (2), and satisfies 0.00≤B/A≤0.10 . . . Expression (2) in the internal region of the sintered body (2).

A multilayer coil component includes a multilayer body in which a plurality of insulating layers are stacked in a stacking direction and a coil inside, and outer electrodes on surfaces of the multilayer body and electrically connected to the coil. The insulating layers have a magnetic phase having spinel structure containing at least Fe, Ni, Zn, and Cu and a non-magnetic phase containing at least Si. When grain sizes D50 and D90 of crystal grains constituting the magnetic phase are respectively defined as equivalent-area circle diameters of 50% and 90% on a cumulative sum basis in a cumulative distribution of equivalent-area circle diameters of the crystal grains, the grain size D50 is from 50 nm to 750 nm, and the grain size D90 is from 200 nm to 1500 nm.

Disclosed herein is a sintered ceramic body comprising from 90% to 99.9% by volume of polycrystalline yttrium aluminum garnet (YAG) as measured using XRD and image processing methods and a volumetric porosity of from 0.1 to 4% as calculated from density measurements performed in accordance with ASTM B962-17. The sintered ceramic body may have a total purity of 99.99% and greater and a grain size of from 0.3 to 8 μm. A method of making the sintered ceramic body is also disclosed.

In a silicon nitride substrate including a silicon nitride sintered body including silicon nitride crystal grains and a grain boundary phase, a plate thickness of the silicon nitride substrate is 0.4 mm or les, and a percentage of a number of the silicon nitride crystal grains including dislocation defect portions inside the silicon nitride crystal grains in a 50 μm×50 μm observation region of any cross section or surface of the silicon nitride sintered body is not less than 0% and not more than 20%. Etching resistance can be increased when forming the circuit board.

A copper-ceramic composite: includes a ceramic substrate containing alumina and a copper or copper alloy coating on the ceramic substrate. The alumina has a mean grain shape factor R.sub.a(Al.sub.2O.sub.3), defined as the arithmetic mean of the shape factors R of the alumina grains, of at least 0.4.

An antiballistic armor-plating component, includes a ceramic body made of a material comprising, as percentages by volume, between 35% and 55% of silicon carbide, between 20% and 50% of boron carbide, between 15% and 35% of a metallic silicon phase or of a metallic phase including silicon.

Provided is a piezoelectric ceramic composition including a potassium sodium niobate-based perovskite type complex oxide represented by Compositional Formula ABO.sub.3, as a main component. Further, the piezoelectric ceramic composition contains Bi in an A site and Zr in a B site. Further, the piezoelectric ceramic composition includes a segregation portion positioned in a crystal grain. At least one of Zr or Bi is localized in the segregation portion.

SiC matrix composite material, where heat-resistant long fiber such as carbon fiber is employed as a material for reinforcement and SiC is employed for the matrix, which significantly improves mechanical properties such as strength and toughness. The SiC matrix composite material, includes a SiC matrix and heat-resistant long fiber, wherein the SiC matrix includes both of alpha-type SiC and beta-type SiC, and the alpha-type SiC and the beta-type SiC are detected by micro-region X-ray diffraction with an X-ray beam diameter of no greater than 300 micrometers substantially at every region of every cross-section of the SiC matrix, the beta-type SiC has an average crystallite size that is no greater than 500 nm and greater than an average crystallite size of the alpha-type SiC, and the SiC matrix composite material has a porosity of no greater than 20% by volume.

A sintered composite ceramic includes a lithium-garnet major phase; and a lithium dendrite growth inhibitor minor phase, such that the lithium dendrite growth inhibitor minor phase comprises lithium tungstate. A method includes sintering a metal oxide component and a garnet component at a temperature in a range of 750° C. to 1500° C. to form a sintered composite ceramic.

Described herein are embodiments directed to additive manufacturing (AM), including three-dimensional (3D) printing, of metal nitride ceramics. In some embodiments herein, AM may comprise powder bed fusion (PBF) techniques. Also described herein are metal nitride ceramic components formed by AM techniques and methods for forming metal nitrides capable of being used in AM processes.