The invention relates to a spark plug connecting element, which includes a first contact element (9a) and a second contact element (9b), a resistor element (8) being situated between the first contact element (9a) and the second contact element (9b), the first contact element (9a) and the second contact element (9b) having a specific conductivity of 10.sup.2 S/m to 10.sup.8 S/m and the resistor element (8) having a specific conductivity of 10.sup.−3 S/m to 10.sup.1 S/m.

A process for the production of a dental shaped body, such as a dental blank or a dental restoration, in which a suspension of a zirconium oxide starting material is gelled by means of a gelling agent, and the use of a suspension of a zirconium oxide starting material as dental material, the suspension containing a gelling agent.

The present invention relates to a novel multi-layered zirconia dental blank comprising at least two reverse layers. Further, the invention relates to a process for the preparation of such a multi-layered zirconia dental blank. The invention also relates to the use of such a multi-layered zirconia dental blank for the production of a dental article. Preferred dental articles are artificial teeth, inlays, onlays, bridges, crowns, veneers, facings, crown frameworks, bridged frameworks, implants, abutments, copings or orthodontic appliances. Moreover, the invention relates to a process for producing a dental article out of such a multi-layered zirconia dental blank.

A composition includes granules in which zirconia particles are aggregated. The granules have an average circularity of 0.81 or greater based on a projected image.

An article has a substrate and a layer atop the substrate. The layer has: a matrix comprising at least one of hafnium silicate (HfSiO.sub.4) and ytterbium disilicate (Yb.sub.2Si.sub.2O.sub.7); and barium magnesium alumino silicate (BMAS).

A zirconia sintered body is provided in which the strength between layers of powders is improved. A flexural strength of a test sample of the zirconia sintered body, measured pursuant to JISR1601, is not less than 1000 MPa. The test sample is formed by preparing a plurality of zirconia powders, each containing zirconia and preferably yttria as a stabilizer that suppresses phase transition of zirconia, the zirconia powders differing in a composition, layering the zirconia powders to form a zirconia composition, and sintering the zirconia composition to form a zirconia sintered body. The flexural strength is measured such that a load point is positioned at a boundary of the zirconia powders, the boundary traversing the test sample of the sintered body along a direction of load application.

A zirconia pre-sintered body suitable for dental milling, grinding and/or cutting can provide a sintered body in which the strength between layers of powders is improved. A flexural strength of a test sample of the zirconia sintered body, measured pursuant to JISR1601, is preferably not less than 1000 or 1100 MPa.

An electrical termination unit or feedthrough which may be used for routing electrical conductors through a chamber wall, or otherwise across a barrier between isolated atmospheric conditions. The electrical termination unit may have aluminum as the interface material to the chamber interface and may utilize a ceramic insulator. The electrical termination unit may have the aluminum used as the interface brazed directly to a ceramic surface of the insulator. The aluminum that forms the chamber interface may be formed within a hollow ceramic tube in the same process step that brazes the aluminum to the ceramic tube with a hermetic joint. Machining subsequent to the brazing of the aluminum to the ceramic insulator may allow for achievement of the final form desired. A method for manufacturing such an electrical termination unit.

A dental zirconia system to produce translucent zirconia sintered bodies comprises at least two separate zirconia green bodies. At least one zirconia green body comprises zirconium oxide and a lower content of at least one other oxide summing to between 6.5 wt % to 20 wt % based on a total weight percent of the zirconia green body. At least another zirconia green body comprises zirconium oxide and a higher content of at least one other oxide summing to between 7.5 wt % to 20 wt % based on a total weight percent of the zirconia green body. The at least two zirconia green bodies each have at least some particles with a diameter of 100 nanometers to 1000 nanometers. The at least two zirconia green bodies have different amounts of the at least one other oxide with respect to one another.

A method for the joining of ceramic pieces with a hermetically sealed joint comprising brazing a layer of joining material between the two pieces. The wetting and flow of the joining material is controlled by the selection of the joining material, the joining temperature, the joining atmosphere, and other factors. The ceramic pieces may be on a non-diffusable type, such as aluminum nitride, alumina, beryllium oxide, and zirconia, and the pieces may be brazed with an aluminum alloy under controlled atmosphere. The joint material is adapted to later withstand both the environments within a process chamber during substrate processing, and the oxygenated atmosphere which may be seen within the shaft of a heater or electrostatic chuck.