A corrosion-resistant member according to the present disclosure includes a substrate that is composed of an aluminum-oxide-based ceramic and a covering layer that is composed of an O—Al—C layer that is located on the substrate.

There is provided a powder material that is for manufacturing a molded article having low porosity and having uniformly present micropores by an additive layer manufacturing method. A powder material for use in additive layer manufacturing contains ceramics and metals, in which a tapped filling rate defined by (tapped density/theoretical density)×100% is 30% or more and less than 40%.

A sintered ball having: a chemical composition such that, in percentages by mass based on the mass of the ball: 89%≤W≤97%; 5%≤C≤8%; Co≤0.5%; Ni≤0.5%; Elements other than W, C, Co, and Ni, or “Other elements”: ≤3%; a tungsten carbide(s) content greater than 55% in percentage by mass based on the crystallized phases; a bulk density greater than or equal to 14 g/cm.sup.3.

A piezoelectric material which is low in load on the environment, and also satisfies both the requirements of a high piezoelectric constant and a high mechanical quality factor. The piezoelectric material comprises a plurality of crystal grains containing Ba, Ca, Ti, Zr, Mn, and O. An average equivalent circle diameter of the crystal grains is not smaller than 1.0 μm and not larger than 10 μm. The crystal grains include crystal grains A each having a first domain with a width of not smaller than 300 nm and not larger than 800 nm, and crystal grains B each having a second domain with a width of not smaller than 20 nm and not larger than 50 nm.

A piezoelectric composition having a complex oxide including potassium and niobium, in which the complex oxide has a first phase represented by a compositional formula KNbO.sub.3, and one or two phases selected from a second phase represented by a compositional formula K.sub.4Nb.sub.6O.sub.17 and a third phase represented by a compositional formula KNb.sub.3O.sub.8.

A refractory object may include a zircon body that is intentionally doped with a dopant including an alkaline earth element and aluminum. The refractory object can have an improved creep deformation rate. In an embodiment, the refractory object can have a creep deformation rate of not greater than about 1.8 E-5 h.sup.−1 at a temperature of 1350° C. and a stress of 2 MPa. In another embodiment, the zircon body may include an amorphous phase including an alkaline earth metal element.

One embodiment of the present invention discloses an electrostatic chuck made of an aluminum nitride sintered body, wherein the aluminum nitride sintered body comprises aluminum nitride and a composite oxide formed along the grain boundaries of the aluminum nitride, wherein the composite oxide comprises at least two kinds of rare earth metals which have a solid-solution relationship with each other, and wherein the composite oxide comprises a collection area having a higher oxygen content than a surrounding area.

Provided is a method for manufacturing a high-density artificial graphite electrode without substantially changing a particle size or a proportion of needle coke used, increasing an amount of binder pitch, or performing extrusion molding at a high molding pressure. The method for manufacturing a high-density artificial graphite electrode is kneading binder pitch into needle coke, performing extrusion molding thereof, and then calcining and graphitizing thereof, wherein needle coke obtained by performing coke shape changing treatment for at least some of pulverized needle coke to be used, thereby increasing a ratio of an enveloping perimeter/a perimeter by 1% or more as compared with a value before the changing is used. Here, the enveloping perimeter is a length of a perimeter when apexes of convex portions of the pulverized needle coke are connected to each other via the shortest distance, and the perimeter is a length of a perimeter of a particle.

The present disclosure belongs to the field of preparation technology and provides an ultralimit alloy and a preparation method therefor. The ultralimit alloy comprises an alloy matrix. A bonding layer and a ceramic layer are successively deposited on a surface of the alloy matrix. The alloy matrix includes one of a magnesium alloy matrix, an aluminium alloy matrix, a titanium alloy matrix, an iron alloy matrix, a nickel alloy matrix, a copper alloy matrix, a zirconium alloy, and a tin alloy. For an ultralimit magnesium alloy, an ultralimit aluminium alloy, an ultralimit nickel alloy, an ultralimit titanium alloy, an ultralimit iron alloy and an ultralimit copper alloy, the bonding layer is a composite bonding layer, the ceramic layer is a composite ceramic layer, and the outside of the composite ceramic layer is further successively deposited with a reflecting layer, a catadioptric layer, an insulating layer and a carbon foam layer.

The invention relates to a method for producing ceramics having piezoelectric properties in predominantly aqueous suspending agents.