The composite sintered body includes AlN and MgAl.sub.2O.sub.4. The open porosity of the composite sintered body is lower than 0.1%. The relative density of the composite sintered body is not lower than 99.5%. The total percentage of the AlN and the MgAl.sub.2O.sub.4 contained in the composite sintered body is not lower than 95 weight percentage and not higher than 100 weight percentage. The percentage of the MgAl.sub.2O.sub.4 contained in the composite sintered body is not lower than 15 weight percentage and not higher than 70 weight percentage. It is thereby possible to provide a high-density composite sintered body having high plasma corrosion resistance, high volume resistivity, and high thermal conductivity.

A method of forming an activated coating composition is disclosed. The method includes providing (a) boron nitride, (b) carbon, (c) aluminum oxide and (d) a liquid carrier. Each of the boron nitride, carbon and aluminum oxide are in particulate form. The coating composition is activated to form an activated coating composition. The activated coating composition includes active components having from about 60.0 wt % to about 90.0 wt % boron nitride, from about 16 wt % to about 24 wt % carbon and from about 4 wt % to about 6 wt % aluminum oxide. A coating method, coated substrate and activated coating composition are also disclosed.

The invention relates to a porous zirconia article in particular for use in the dental or orthodontic field, the porous zirconia article comprising ZrO.sub.2: 80 to 87 wt. %, Y.sub.2O.sub.3: 3 to 5 wt. %, Al.sub.2O.sub.3: 10 to 14 wt. %, wt. % with respect to the weight of the porous zirconia article, the porous zirconia article being characterized by a BET surface from 15 to 100 m.sup.2/g. The invention also relates to a sintered zirconia article in particular for use in the dental or orthodontic field, the sintered zirconia article comprising ZrO.sub.2: 80 to 87 wt. %, Y.sub.2O.sub.3: 3 to 5 wt. %, Al.sub.2O.sub.3: 10 to 14 wt. %, wt. % with respect to the weight of the porous zirconia article, the sintered zirconia article being characterized by a corundum crystal phase content of 7 to 12 wt. % and a flexural strength of at least 2,000 MPa.

A long-term ablation-resistant nitrogen-containing carbide ultra-high temperature ceramic with an ultra-high melting point is prepared as follows: preparing the HfC powder and the HfN powder according to a mass ratio of HfC:HfN=(1-7):1; uniformly mixing the HfC powder and the HfN powder with the carbon powder and the carbon nitride powder to obtain a mixed powder, wherein the amount of the carbon powder and the amount of the carbon nitride powder do not exceed 8.0 wt. % and 5.0 wt. %, respectively, of the mixed powder mass; and performing spark plasma sintering on the mixed powder to produce the ceramic with the ultra-high melting point, a density ≥98%, and a uniform C/N content distribution. The ultra-high temperature ceramic is suitable for ultra-high temperature ablation-resistant protection at ≥3000° C. The ceramic maintains a close to zero ablation rate and a continuously stable oxidation-resistant protective structure after ablation for 300 s.

A thermal barrier coating (TBC) top coat which is a high entropy oxide (HEO) having a high configurational entropy, contains at least 5 different oxide-forming metallic cations, is a single phase or single crystalline structure, such as tetragonal or cubic over unexpectedly wide temperature ranges up to and beyond top coat operating temperatures of preferably at least 2300° F. The TBC top coats exhibit low thermal conductivity, good sintering resistance, excellent phase stability and good thermal cycling performance. At least five of the different oxide-forming metallic cations include: a) at least one of the transition metals: Sc, Y, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Co, Ni, Cu, or Zn, and/or at least one of the lanthanides La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb. Dy, Ho, Er, Yb, or Lu. One of the at least five different oxide-forming metallic cations may also comprise at least one of the alkaline-earth metals: Be, Mg, Ca, Sr, or Ba.

In one aspect, the present invention comprises providing an additive or aggregate to be applied directly to one or more of the components of a ceramic coating and which is constituted by carbonate apatites particles which are maintained as aggregates within a matrix of silicoaluminates at firing temperatures of the ceramic coatings, where the main function of these aggregates is to provide the ceramic coating properties selected from the group comprising: low effusivity, wear resistance, resistance to chemical attack and resistance to staining. In other aspects, the present invention comprises providing a ceramic coating incorporating said additive and a method for providing a ceramic coating with properties selected from the group comprising: low effusivity, wear resistance, resistance to chemical attack and resistance to staining.

Disclosed are a sagger for sintering lithium composite transition metal oxide and a preparation method thereof. The sagger includes a substrate layer and a shallow layer on a surface of the substrate layer, and a coating layer. The substrate layer is prepared from the following raw materials: silicon carbide, magnesia-alumina spinel, aluminum oxide-magnesium oxide-yttrium oxide composite fiber, zircon powder and a binding agent; the shallow layer is prepared from the following raw materials: silicon carbide, magnesia-alumina spinel, aluminum oxide-titanium oxide composite fiber, yttrium oxide-zirconium oxide composite fiber and a binding agent; and the coating layer is prepared from the following raw materials: silicon carbide, magnesia-alumina spinel, magnesium oxide, zirconium oxide fiber, lithium composite transition metal oxide powder and a binding agent. The sagger of the present disclosure has properties of good corrosion resistance and a small coefficient of thermal expansion.

A thermal barrier coating composition comprises: A. a binder in an amount from about 1% wt. % to about 15 wt. % and: B. a zirconia-containing powder comprising: I. up to about 65 wt. % of a component comprising: a. a first metal oxide selected from the group including ytterbia, neodymia, mixtures of ytterbia and neodymia, mixtures of ytterbia and lanthana, mixtures of neodymia and lanthana, and mixtures of ytterbia, neodymia and lanthana in an amount of from about 8 wt. % to about 55 wt. % of the component; and b. a second metal oxide selected from the group including yttria, calcia, ceria, scandia, magnesia, india and mixtures thereof in an amount up to about 2 wt. % or less of the component; and II. one or more of a third metal oxide selected from the group including: a. hafnia in an amount up to about 2 wt. % or less of the component; and b. tantala in an amount up to about 2 wt. % or less of the component; and and a balance zirconia by weight.

Disclosed is to provide a composite structure used as a member for a semiconductor manufacturing apparatus with which low-particle generation can be improved, as well as a semiconductor manufacturing apparatus including the same. A composite structure including a base material and a structure that is provided on the base material and has a surface, in which the structure comprises Y.sub.3Al.sub.5O.sub.12 as a main component, and has an indentation hardness being larger than 8.5 GPa features excellent low-particle generation and is suitably used as a member for a semiconductor apparatus.

Materials systems resistant to penetration of molten salts and may be present within a molten-salt-facing wall of a device for containing a molten salt bath at an elevated temperature, and molten-salt-facing walls and devices formed by such materials systems. A first layer of such a system defines an outer surface for direct contact with the molten salt bath, and resists erosion and corrosion and is penetrable by the molten salt at the elevated temperature. A second layer is located adjacent to the first layer and exhibits little or no wetting by the molten salt so that at least a portion of a thickness of the second layer is not penetrable by the molten salt. A third layer is located adjacent to the second layer and is porous and exhibits a low thermal conductivity at the elevated temperature.