An electromagnetic wave absorbing particle has a composition, which is represented by Formula 1 of Sr.sub.1-xR.sub.xFe.sub.y-2zM.sub.2zO.sub.a and contains M-type hexaferrite as a main phase. In Formula 1, R is one or more substances selected from among Ba, Ca, and La, M is one or more substances selected from among Co, Ti, and Zr, 0<x≤0.8, 8≤y≤14, 0<z≤1.5, and a is equal to 19.

The magnet is a ferrite sintered magnet containing a ferrite phase having a magnetoplumbite-type crystal structure. The ferrite sintered magnet contains at least Ca, a metal element A, a metal element R, Bi, Fe, and a metal element M. The metal element A is at least one kind of element selected from the group consisting of Sr, Ba, and Pb, the metal element R is at least one kind of element selected from the group consisting of rare-earth elements including Y and essentially includes La, the metal element M is at least one kind of element selected from the group consisting of Co, Ni, Zn, Al, Cu, and Cr, and essentially includes Co, and when an atonic ratio of the metal elements is expressed by Formula (1), c, a, r, b, f, and m in Formula (1) satisfy the following Expressions (2) to (8).

In an aspect, a ferrite composition can comprise a SbCo—M-type ferrite having the formula: Me.sub.1-xSb.sub.xCo.sub.y+xM′.sub.yFe.sub.12-x-2yO.sub.19, wherein Me is at least one of Sr, Pb, or Ba; M′ is at least one of Ti, Zr, Ru, or Ir; x is 0.001 to 0.3; and y is 0.8 to 1.3. In another aspect, a method of making the ferrite composition comprises mixing ferrite precursor compounds comprising Me, Fe, Sb, Co, and M; and sintering the ferrite precursor compounds in an oxygen atmosphere to form the SbCo—M-type ferrite. In yet another aspect, a composite comprises the ferrite composition and a polymer. In still another aspect, an article comprises the ferrite composition.

In an aspect, a Co.sub.2Z-type ferrite comprises oxides of at least Me, Co, Mo, Li, and Fe; wherein Me is at least one of Ba or Sr. In another aspect, the Co.sub.2Z-type ferrite comprises a Z-type hexaferrite an amount of lithium molybdate. In another aspect, the Co.sub.2Z-type ferrite has a formula Li.sub.2MoO.sub.4.Ba.sub.xSr.sub.3-xCo.sub.2+y−zMe′.sub.yMe″.sub.zFe.sub.24-2y-mO.sub.41, wherein Me′ is at least one of Ti, Mo, Ru, Ir, Zr, or Sn; Me″ is at least one of Zn, Mn, or Mg; x is 0 to 3; y is 0 to 1.8; z is 0 to 1.8; and m is −4 to 4. In yet another aspect, a method of making a Co.sub.2Z-type ferrite comprises milling an initial Co.sub.2Z-type ferrite and Li.sub.2MoO.sub.4 to form a mixed ferrite; and calcining the mixed ferrite to form the Co.sub.2Z-type ferrite.

A thermochromic polymeric nanocomposite includes layered double hydroxides (LDHs) and an embedded organic polymer. The thermochromic polymeric nanocomposite exhibits thermochromic activity, e.g., changes in color in response to a change in higher temperatures. The higher temperatures can range from 100° C.-150° C. or higher. As such, the thermochromic polymeric nanocomposite can be used to monitor temperature changes for materials approaching very high temperatures.

A film contains a fluororesin, a chromatic pigment, and a black pigment, in which a visible light transmittance of the film is from 5 to 60% and a haze value of the film is 30% or less.

In an aspect, a ferrite composition comprises a Ru—Co.sub.2Z ferrite having the formula: (Ba.sub.3-xM.sub.x)Co.sub.2(M′Ru).sub.yFe.sub.24-2y-zO.sub.41, wherein M is at least one of Sr, Pb, or Ca; M′ is at least one of Co, Zn, Mg, or Cu; x is 1 to 3; y is greater than 0 to 2; and z is −4 to 4. In another aspect, an article comprises the ferrite composition. In yet another aspect, method of making the ferrite composition comprises mixing ferrite precursor compounds comprising Fe, Ba, Co, and Ru; and sintering the ferrite precursor compounds in an oxygen atmosphere to form the Ru—Co.sub.2Z ferrite.

To provide a high emissivity coating composition capable of exhibiting a higher emissivity at a low elevated temperature and substantially reduced formation micro craze when coated upon a substrate, and enabling a simplified application process, a high emissivity coating composition, comprising a powder mixture for providing emissivity; a binder for providing adhesion; and a co-binder for promoting adhesion and film-forming, characterized in that the powder mixture comprises at least three metal compounds of formula A.sub.(y−3)B.sub.y/2O.sub.y, wherein y is 4; A is selectable from a group of Ni and Co; B is selectable from a group of Fe and Cr; and O is oxygen; and the co-binder is an aqueous solution comprising silica in a compound of Formula (1), wherein R.sub.1 is H—Si—(CH.sub.3).sub.2; and a compound of Formula (2), wherein R.sub.2 is CH.sub.3, is disclosed herein.

The magnet is a ferrite sintered magnet containing a ferrite phase having a magnetoplumbite-type crystal structure. The ferrite sintered magnet contains at least Ca, a metal element A, a metal element R, Bi, Fe, and a metal element M. The metal element A is at least one kind of element selected from the group consisting of Sr, Ba, and Pb, the metal element R is at least one kind of element selected from the group consisting of rare-earth elements including Y and essentially includes La, the metal element M is at least one kind of element selected from the group consisting of Co, Ni, Zn, Al, Cu, and Cr, and essentially includes Co, and when an atonic ratio of the metal elements is expressed by Formula (1), c, a, r, b, f, and m in Formula (1) satisfy the following Expressions (2) to (8).

A polymer includes a repeating unit represented by at least one of Formula 1a or Formula 1b: ##STR00001## wherein, in Formulae 1a or 1b, CY.sub.1 is a group represented by at least one of Formula 1-2 or Formula 1-4, CY.sub.2 is a group represented by Formula 1-3, and L.sub.1, L.sub.2, a1, and a2 are defined the same as in the specification, and ##STR00002## in Formulae 1-2, Formula 1-3, or 1-4, X, Y, R.sub.1, R.sub.2, R.sub.11 to R.sub.14, b1, b2, R.sub.21, R.sub.22, b21, b22, Z.sub.1, Z.sub.2, c1, and c2 are defined the same as in the specification.