A ceramic composite can include a first ceramic phase and a second ceramic phase. The first ceramic phase can include a silicon carbide. The second phase can include a boron carbide. In an embodiment, the silicon carbide in the first ceramic phase can have a grain size in a range of 0.8 to 200 microns. The first phase, the second phase, or both can further include a carbon. In another embodiment, at least one of the first ceramic phase and the second ceramic phase can have a median minimum width of at least 5 microns.

A refractory object may include a zircon body that may include at least about 0.1 wt. % and not greater than about 5.5 wt. % of an Al.sub.2O.sub.3 containing component for a total weight of the zircon body. The zircon body may further include at least about 25 wt. % and not greater than about 35 wt. % of a SiO.sub.2 component for a total weight of the zircon body.

The present document generally relates to additive manufacturing techniques for forming an article having a desired shape and other properties. More particularly, but not exclusively, in one embodiment a method for additive manufacturing an article includes adding a dispersant to an article forming material in the absence of binder to prepare a slurry or suspension including the material and the dispersant. The pH of the slurry may be adjusted to control the viscosity and/or coagulation rate of the slurry. The slurry may then be passed through an extrusion-based three-dimensional printing apparatus to form or print the article in a desired form or shape, and the article may thereafter be sintered. In one aspect, through control of the pH of the slurry, the viscosity and/or coagulation rate properties of the slurry may be tailored for use with different operating parameters of the extrusion-based three-dimensional printing apparatus.

A honeycomb structure includes a honeycomb structure body having a partition wall which is constituted of a porous body. The porous body includes a refractory aggregate and a bonding material. The porous body constituting includes the bonding material at a mass proportion of 20 to 35 mass %. In an observation of a cross section of the partition wall with an electron microscope, when observing any given ten visual fields meeting a following condition (1), the number of refractory aggregates meeting a following condition (2) is five pieces or more in all of the ten visual fields. Condition (1): a proportion of an area occupied by the bonding material is 30% or more. Condition (2): the refractory aggregate has a particle diameter of 5 μm or more, and 60% or more of an outer circumference of the refractory aggregate is surrounded by the bonding material.

Provided is a lead-free piezoelectric material having satisfactory piezoelectric constant and mechanical quality factor in a device driving temperature range (−30° C. to 50° C.) The piezoelectric material includes a main component containing a perovskite-type metal oxide represented by Formula 1, a first auxiliary component composed of Mn, and a second auxiliary component composed of Bi or Bi and Li. The content of Mn is 0.040 parts by weight or more and 0.500 parts by weight or less based on 100 parts by weight of the metal oxide on a metal basis. The content of Bi is 0.042 parts by weight or more and 0.850 parts by weight or less and the content of Li is 0.028 parts by weight or less (including 0 parts by weight) based on 100 parts by weight of the metal oxide on a metal basis. (Ba.sub.1-xCa.sub.x).sub.a(Ti.sub.1-yZr.sub.y)O.sub.3 . . . (1), wherein, 0.030≦x<0.090, 0.030≦y≦0.080, and 0.9860≦a≦1.0200.

A refractory article can include a body including a content of alumina of at least 60 wt %, a content of silica of not greater than 20 wt %, a content of zirconia of not greater than 20 wt % for a total weight of the body. In a particular embodiment, the body includes a third phase including composite grains including mullite and zirconia. The third phase including the composite grains can be present within a range including at least 1 wt % and not greater than 35 wt % for a total weight of the body.

A ceramic structure of the present disclosure is provided with: a first member made of a single crystal of sapphire or an yttrium aluminum composite oxide; and a second member in contact with the first member, the second member being made of ceramic containing an aluminum oxide or an yttrium aluminum composite oxide as a principal component, wherein, of crystal grains constituting the second member, contact grains of the second member, which are grains in contact with the first member, include a first curved surface part that is convex toward the first member.

A sintered MnZn ferrite body containing main components comprising 53.30-53.80% by mol of Fe calculated as Fe.sub.2O.sub.3, 6.90-9.50% by mol Zn calculated as ZnO, and the balance of Mn calculated as MnO, and sub-components comprising 0.003-0.020 parts by mass of Si calculated as SiO.sub.2, more than 0 parts and 0.35 parts or less by mass of Ca calculated as CaCO.sub.3, 0.30-0.50 parts by mass of Co calculated as Co.sub.3O.sub.4, 0.03-0.10 parts by mass of Zr calculated as ZrO.sub.2, and 0-0.05 parts by mass of Ta calculated as Ta.sub.2O.sub.5, pre 100 parts by mass in total of the main components (calculated as the oxides), and having an average crystal grain size of 3 μm or more and less than 8 μm and a density of 4.65 g/cm.sup.3 or more.

A cutting tool comprises a rake face and a flank face, the cutting tool being composed of a substrate made of a cubic boron nitride sintered material and a coating provided on the substrate, the coating including a MAlN layer, when a cross section of the MAlN layer is subjected to an electron backscattering diffraction image analysis to determine a crystal orientation of each of the crystal grains of the M.sub.xAl.sub.1−xN and a color map is created based thereon, then on the color map, the flank face having the MAlN layer occupied in area by 45% to 75% by crystal grains of the M.sub.xAl.sub.1−xN having a (111) plane with a normal thereto extending in a direction within 25 degrees with respect to a direction in which a normal to the flank face extends, the MAlN layer having a residual stress of −2 GPa to −0.1 GPa.

A method for manufacturing a ceramic article including (i) a step of irradiating a powder mainly containing a ceramic material with an energy beam to sinter or melt and solidify the powder into a solidified portion, wherein the step is repeated a predetermined number of times to sequentially bond the resulting solidified portions together to obtain a ceramic modeling object, (ii) a step of allowing the shaped ceramic object to absorb a metal component-containing liquid that contains inorganic particles containing a metal element; and (iii) a step of heating the shaped ceramic object that has absorbed the metal component-containing liquid.