The present invention relates a coating powder comprising a rare earth oxyfluoride (Ln-O—F) and having: an average particle size (D.sub.50) of 0.1 to 10 μm, a pore volume of pores having a diameter of 10 μm or smaller of 0.1 to 0.5 cm.sup.3/g as measured by mercury intrusion porosimetry, and a ratio of the maximum peak intensity (S0) assigned to a rare earth oxide (Ln.sub.xO.sub.y) in the 2θ angle range of from 20° to 40° to the maximum peak intensity (S1) assigned to the rare earth oxyfluoride (Ln-O—F) in the same range, S0/S1, of 1.0 or smaller in powder X-ray diffractometry using Cu-Kα rays or Cu-Kα.sub.1 rays.

An electrode can include a functional layer having an Ln.sub.2MO.sub.4 phase, where Ln is at least one lanthanide optionally doped with a metal and M is at least one 3d transition metal, and a heavily-doped ceria phase. An electrochemical device or a sensor device can include the electrode.

An electrode can include a functional layer having an Ln.sub.2MO.sub.4 phase, where Ln is at least one lanthanide optionally doped with a metal and M is at least one 3d transition metal, and a heavily-doped ceria phase. An electrochemical device or a sensor device can include the electrode.

Disclosed are a ten-membered fergusonite structure high-entropy oxide ceramic and a preparation method thereof, where the high-entropy oxide ceramic has a monoclinic structure, with a chemical formula of RENbO.sub.4, and the RE is any ten rare-earth cations selected from a group consisting of La.sup.3+, Ce.sup.3+, Pr.sup.3+, Nd.sup.3+, Sm.sup.3+, Eu.sup.3+, Gd.sup.3+, Dy.sup.3+, Ho.sup.3+, Er.sup.3+, Tm.sup.3+, Yb.sup.3+, Lu.sup.3+ and Y.sup.3+. The ten rare-earth cations have a molar ratio of 1:1:1:1:1:1:1:1:1:1 and equal share of RE position. According to the application, by adopting solid state reaction, the fergusonite structure high-entropy oxide ceramic with single-phase structure, uniform element distribution and stable phase is obtained. The high-entropy oxide ceramic prepared by the application is simple in process, uniform in chemical composition and microstructure, and convenient to realize on-demand regulation on properties through a combination of different elements.

Disclosed are a ten-membered fergusonite structure high-entropy oxide ceramic and a preparation method thereof, where the high-entropy oxide ceramic has a monoclinic structure, with a chemical formula of RENbO.sub.4, and the RE is any ten rare-earth cations selected from a group consisting of La.sup.3+, Ce.sup.3+, Pr.sup.3+, Nd.sup.3+, Sm.sup.3+, Eu.sup.3+, Gd.sup.3+, Dy.sup.3+, Ho.sup.3+, Er.sup.3+, Tm.sup.3+, Yb.sup.3+, Lu.sup.3+ and Y.sup.3+. The ten rare-earth cations have a molar ratio of 1:1:1:1:1:1:1:1:1:1 and equal share of RE position. According to the application, by adopting solid state reaction, the fergusonite structure high-entropy oxide ceramic with single-phase structure, uniform element distribution and stable phase is obtained. The high-entropy oxide ceramic prepared by the application is simple in process, uniform in chemical composition and microstructure, and convenient to realize on-demand regulation on properties through a combination of different elements.

Disclosed is a solid state electrolyte comprising a compound of Formula 1

Li.sub.7-.sub.a.sub.*α-(b−4)*β−xM.sup.a.sub.αLa.sub.3Hf.sub.2−βM.sup.b.sub.βO.sub.12−x−δX.sub.x   (1)

wherein

M.sup.a is a cationic element having a valence of a+;

M.sup.b is a cationic element having a valence of b+; and

X is an anion having a valence of −1,

wherein, when M.sup.a includes H, 0≤α≤5, otherwise 0≤α≤0.75, and wherein 0≤β≤1.5, 0≤x≤1.5, and (a*α+(b−4)β+x)>0, 0≤δ≤1.

An abrasive particle having a body including a first major surface, a second major surface opposite the first major surface, and a side surface extending between the first major surface and the second major surface, such that a majority of the side surface comprises a plurality of microridges.

Embodiments of the present disclosure relate to articles, coated articles and methods of coating such articles with a rare earth metal containing oxide coating. The coating can contain at least a first metal (e.g., a rare earth metal, tantalum, zirconium, etc.) and a second metal that have been co-deposited onto a surface of the article. The coating can include a homogenous mixture of the first metal and the second metal and does not contain mechanical segregation between layers in the coating.

Embodiments of the present disclosure relate to articles, coated articles and methods of coating such articles with a rare earth metal containing oxide coating. The coating can contain at least a first metal (e.g., a rare earth metal, tantalum, zirconium, etc.) and a second metal that have been co-deposited onto a surface of the article. The coating can include a homogenous mixture of the first metal and the second metal and does not contain mechanical segregation between layers in the coating.

A method includes performing ion beam sputtering with ion assisted deposition to deposit a protective layer on a surface of a body. The protective layer is a plasma resistant rare earth-containing film of a thickness less than 1000 .Math.m. The porosity of the protective layer is below 1%. The plasma resistant rare earth-containing film consists of 40 mol% to less than 100 mol% of Y.sub.2O.sub.3, over 0 mol% to 60 mol% of ZrO.sub.2, and 0 mol% to 9 mol% of Al.sub.2O.sub.3.