An oxide superconductor of an embodiment includes an oxide superconductor layer having a continuous Perovskite structure containing rare earth elements, barium (Ba), and copper (Cu). The rare earth elements contain a first element which is praseodymium (Pr), at least one second element selected from the group consisting of neodymium (Nd), samarium (Sm), europium (Eu), and gadolinium (Gd), at least one third element selected from the group consisting of yttrium (Y), terbium (Tb), dysprosium (Dy), and holmium (Ho), and at least one fourth element selected from the group consisting of erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

Provided is a noble metal material for 3D printing, the noble metal material including an alloy that contains gold (Au) and a first metal that is different from the gold, wherein the alloy contains about 50 wt % to about 100 wt % of the gold and contains more than about 0 wt % and at most about 50 wt % of the first metal, and the melting point of the alloy is at most 400 C.

Provided is a noble metal material for 3D printing, the noble metal material including an alloy that contains gold (Au) and a first metal that is different from the gold, wherein the alloy contains about 50 wt % to about 100 wt % of the gold and contains more than about 0 wt % and at most about 50 wt % of the first metal, and the melting point of the alloy is at most 400 C.

A method of producing polycrystalline Y.sub.3Ba.sub.5Cu.sub.8O.sub.y (Y-358) whereby powders of yttrium (III) oxide, a barium (II) salt, and copper (II) oxide are pelletized, calcined at 850 to 950 C. for 8 to 16 hours, ball milled under controlled conditions, pelletized again and sintered in an oxygen atmosphere at 900 to 1000 C. for up to 72 hours. The polycrystalline Y.sub.3Ba.sub.5Cu.sub.8O.sub.y thus produced is in the form of elongated crystals having an average length of 2 to 10 m and an average width of 1 to 2 m, and embedded with spherical nanoparticles of yttrium deficient Y.sub.3Ba.sub.5Cu.sub.8O.sub.y having an average diameter of 5 to 20 nm. The spherical nanoparticles are present as agglomerates having flower-like morphology with an average particles size of 30 to 60 nm. The ball milled polycrystalline Y.sub.3Ba.sub.5Cu.sub.8O.sub.y prepared under controlled conditions shows significant enhancement of superconducting and flux pinning properties.

The invention relates to a material for storing and releasing oxygen, consisting of a reactive ceramic made of copper, manganese and iron oxides, wherein, subject to the oxygen partial pressure of a surrounding atmosphere and/or an ambient temperature, the reactive ceramic has a transition region that can be passed through any number of times, said transition region being between a discharge threshold state of a three-phase crednerite/cuprite/hausmannite mixed ceramic and a charge threshold state of a two-phase spinel/tenorite mixed ceramic. A passing through of the transition region from the discharge threshold state towards the charging threshold state is associated with oxygen uptake and a passing through of the transition region from the charge threshold state towards the discharge threshold state is associated with oxygen release.

The invention relates to a material for storing and releasing oxygen, consisting of a reactive ceramic made of copper, manganese and iron oxides, wherein, subject to the oxygen partial pressure of a surrounding atmosphere and/or an ambient temperature, the reactive ceramic has a transition region that can be passed through any number of times, said transition region being between a discharge threshold state of a three-phase crednerite/cuprite/hausmannite mixed ceramic and a charge threshold state of a two-phase spinel/tenorite mixed ceramic. A passing through of the transition region from the discharge threshold state towards the charging threshold state is associated with oxygen uptake and a passing through of the transition region from the charge threshold state towards the discharge threshold state is associated with oxygen release.

A ceramic composition in one embodiment contains, relative to 100 parts by mass of diopside crystal powder, 0.3 to 1.5 parts by mass of a Li component in terms of an oxide thereof and 0.1 to 1 part by mass of a B component in terms of an oxide thereof. In this embodiment, the content of the Li component in terms of an oxide thereof is larger than the content of the B component in terms of an oxide thereof. In this embodiment, a total content of the Li component and the B component is 2.25 parts by mass or less in terms of oxides thereof

A ceramic composition in one embodiment contains, relative to 100 parts by mass of diopside crystal powder, 0.3 to 1.5 parts by mass of a Li component in terms of an oxide thereof and 0.1 to 1 part by mass of a B component in terms of an oxide thereof. In this embodiment, the content of the Li component in terms of an oxide thereof is larger than the content of the B component in terms of an oxide thereof. In this embodiment, a total content of the Li component and the B component is 2.25 parts by mass or less in terms of oxides thereof

A superconducting coil of an embodiment includes a superconducting wire including an oxide superconductor layer. The oxide superconductor layer has a continuous Perovskite structure including rare earth elements, barium (Ba), and copper (Cu). The rare earth elements include a first element which is praseodymium (Pr), at least one second element selected from the group consisting of neodymium (Nd), samarium (Sm), europium (Eu), and gadolinium (Gd), at least one third element selected from the group consisting of yttrium (Y), terbium (Tb), dysprosium (Dy), and holmium (Ho), and at least one fourth element selected from the group consisting of erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

A composite body of the present invention includes a base and an oxide layer arranged on the base, the oxide layer containing more than 45% by volume of a perovskite-type oxide phase. The composite body may include a first member, a second member, and a joining portion that joins the first member and the second member, at least one of the first member and the second member serving as the base, and the joining portion serving as the oxide layer. The composite body may include the base and a covering portion that covers the whole or part of a surface of the base, the covering portion being formed of the oxide layer.