A ceramic composite and a method of preparing the same are provided. The method of preparing the ceramic composite includes mixing an aluminum slag and a carbon accelerator to obtain a mixture and reacting the mixture at a temperature equal to or greater than 1600° C. in a nitrogen atmosphere to obtain a ceramic composite. The aluminum slag includes aluminum, oxygen, nitrogen, and magnesium. The weight ratio of the oxygen to the aluminum is 0.6 to 2. The weight ratio of the nitrogen to the aluminum is 0.1 to 1.2. The weight ratio of the magnesium to the aluminum is 0.04 to 0.2. The ceramic composite includes aluminum nitride accounting for at least 90 wt % of the ceramic composite.

Provided are novel high entropy nitrides (HENs) exhibiting excellent physical and chemical properties. Also provided are systems and methods to synthesize bulk HENs by reaction flash sintering. Commercial metal nitride powders can be consolidated into near fully dense single-phase bulk ceramic with a proprietary flash sintering apparatus. A constant DC electrical field of ˜80 V/cm and pressure of ˜15 MPa at room temperature can trigger reaction flash sintering without pre-heating, and the entire process can finish in ˜250 seconds to ˜400 seconds.

Provided are novel high entropy nitrides (HENs) exhibiting excellent physical and chemical properties. Also provided are systems and methods to synthesize bulk HENs by reaction flash sintering. Commercial metal nitride powders can be consolidated into near fully dense single-phase bulk ceramic with a proprietary flash sintering apparatus. A constant DC electrical field of ˜80 V/cm and pressure of ˜15 MPa at room temperature can trigger reaction flash sintering without pre-heating, and the entire process can finish in ˜250 seconds to ˜400 seconds.

One aspect of the present invention provides a composite sheet which comprises a nitride sintered body having a porous structure and a semi-cured product of a thermosetting resin composition impregnated into the nitride sintered body, the line roughness Rz specified by JIS B 0601:2013 of at least one main surface being 10 μm or less.

One aspect of the present invention provides a composite sheet which comprises a nitride sintered body having a porous structure and a semi-cured product of a thermosetting resin composition impregnated into the nitride sintered body, the line roughness Rz specified by JIS B 0601:2013 of at least one main surface being 10 μm or less.

The invention relates to a method for producing a metal-ceramic substrate and to a furnace suitable for carrying out the method. With the method, a metal-ceramic substrate with increased thermal and current conductivity can be obtained. The method comprises the steps of providing a stack containing a ceramic body, a metal foil, and a solder material in contact with the ceramic body and the metal foil, the solder material comprising a metal having a melting point of at least 700° C., a metal having a melting point of less than 700° C., and an active metal, and heating the stack, the stack passing through a heating zone for heating.

The invention relates to a method for producing a metal-ceramic substrate and to a furnace suitable for carrying out the method. With the method, a metal-ceramic substrate with increased thermal and current conductivity can be obtained. The method comprises the steps of providing a stack containing a ceramic body, a metal foil, and a solder material in contact with the ceramic body and the metal foil, the solder material comprising a metal having a melting point of at least 700° C., a metal having a melting point of less than 700° C., and an active metal, and heating the stack, the stack passing through a heating zone for heating.

Articles may be protected against halide plasma, by applying a rare earth-containing glaze to the surface of the article. The glaze may be a coating comprising; 20 to 90 mol % SiO.sub.2, 0 to 60 mol % Al.sub.2O.sub.3, 10 to 80 mol % rare earth oxides and/or rare earth fluorides (REX), wherein SiO.sub.2+Al.sub.2O.sub.3+REX≥60 mol %.

Articles may be protected against halide plasma, by applying a rare earth-containing glaze to the surface of the article. The glaze may be a coating comprising; 20 to 90 mol % SiO.sub.2, 0 to 60 mol % Al.sub.2O.sub.3, 10 to 80 mol % rare earth oxides and/or rare earth fluorides (REX), wherein SiO.sub.2+Al.sub.2O.sub.3+REX≥60 mol %.

A plasma processing device member according to the disclosure includes a base material and a film formed of a rare-earth element oxide, or a rare-earth element fluoride, or a rare-earth element oxyfluoride, or a rare-earth element nitride, the film being disposed on at least part of the base material. The film includes a surface to be exposed to plasma, the surface having an arithmetic mean roughness Ra of 0.01 μm or more and 0.1 μm or less, the surface being provided with a plurality of pores, and a value obtained by subtracting an average equivalent circle diameter of the pores from an average distance between centroids of adjacent pores is 28 μm or more and 48 μm or less. A plasma processing device according to the disclosure includes the plasma processing device member described above.