A copper-ceramic composite: includes a ceramic substrate containing alumina and a copper or copper alloy coating on the ceramic substrate. The alumina has a mean grain shape factor R.sub.a(Al.sub.2O.sub.3), defined as the arithmetic mean of the shape factors R of the alumina grains, of at least 0.4.

A polycrystalline super hard construction comprises a body of polycrystalline super hard material and a substrate bonded to the body along an interface. The substrate a first end surface forming the interface, the first end surface comprising a projection extending from the body of the substrate into the body of super hard material towards the cutting face, the body of polycrystalline material extending around the projection. The body of polycrystalline material comprises a first region more thermally stable than a second region, the first region comprising an annular portion located around the projection, the second region extending between and bonding the first region to the substrate. The first region has a thickness from the cutting face along the peripheral side edge to the interface of at least around 3 mm and a portion of the projection has a thickness measured in a plane extending along the longitudinal axis of at least around 3 mm.

The invention relates to a copper-ceramic composite, comprising a ceramic substrate, which contains aluminum oxide, a coating on the ceramic substrate made of copper or a copper alloy, wherein the aluminum oxide has an average grain form factor R.sub.a(Al.sub.2O.sub.3), determined as an arithmetic average value from the form factors of the grains of the aluminum oxide, the copper or the copper alloy has an average grain form factor R.sub.a(Cu), determined as an arithmetic average of the form factors of the grains of the copper or copper alloy, and the average grain form factors of the aluminum oxide and copper or copper alloy meet the following condition: 0.5≤R.sub.a(Al.sub.2O.sub.3)/R.sub.a(Cu)≤2.0.

A method for producing a metal-ceramic substrate with a plurality of electrically conductive vias includes: attaching a first metal layer in a planar manner to a first surface side of a ceramic layer; after attaching the first metal layer, introducing a copper hydroxide or copper acetate brine into a plurality of holes in the ceramic layer delimiting a via, to form an assembly; converting the copper hydroxide or copper acetate brine into copper oxide; subjecting the assembly to a high-temperature step above 500° C. in which the copper oxide forms a copper body in the plurality of holes; and after converting the copper hydroxide or copper acetate brine into the copper oxide, attaching a second metal layer in a planar manner to a second surface side of the ceramic layer opposite the first surface side. The copper body produces an electrically conductive connection between the first and the second metal layers.

A hard lead zirconate titanate (PZT) ceramic has an ABO.sub.3 structure with A sites and B sites. The PZT ceramic is doped with Mn and with Nb on the B sites and the ratio Nb/Mn is <2. A piezoelectric multilayer component having such a PZT ceramic and also a method for producing a piezoelectric multilayer component are also disclosed.

The invention relates to a process for producing a metal-ceramic substrate (1), comprising: providing a ceramic element (10) and a metal layer, providing a gas-tight container (25) that encloses the ceramic element (10), the container (25) preferably being formed from the metal layer or comprising the metal layer, forming the metal-ceramic substrate (1) by connecting the metal layer to the ceramic element (10) by means of hot isostatic pressing, wherein, for the purpose of forming the metal-ceramic substrate (1), an active metal layer (15) or a contact layer comprising an active metal is arranged at least in some sections between the metal layer and the ceramic element (10) for supporting the connection of the metal layer to the ceramic element (10).

When a laminate of a plurality of different materials including a metal plate is bonded in a pressurized and heated state, a first pressurizing member in which a first metal foil/a carbon sheet or a ceramic sheet/a graphite sheet are laminated in this order is arranged so that the first metal foil is in contact with a surface of the first metal plate of the laminate, the first metal foil is made of a material that does not react at a contact surface of the first plate member and the first metal foil when heating, and a product of a Young's modulus (GPa) and a thickness (mm) of the first metal foil is 0.6 or more and 100 or less, so that a good bonded body can be manufactured by evenly pressurizing the laminate and foreign substances can be restrained from adhering to the surface of the laminate.

Polycrystalline cubic boron nitride compact include a body having sintered microcrystalline cubic boron nitride in a matrix of binder material. The microcrystalline cubic boron nitride particles have a size ranging from 2 microns to 50 microns. The particles of microcrystalline cubic boron nitride include a plurality of sub-grains, each sub-grain having a size ranging from 0.1 micron to 2 microns. The compacts are manufactured in a high pressure—high temperature (HPHT) sintering process. The compacts exhibit intergranular defect formation following introduction of wear. The sub-grains promote crack propagation based on micro-chipping rather than on a cleavage mechanism and, in sintered bodies, cracks propagate intergranularly rather than intragranularly, resulting in increased toughness and improved wear characteristics as compared to monocrystalline cubic boron nitride. The compacts are suitable for use as abrasive tools.

A multilayer component and a mathod for producing a multilayer component are disclosed. In an embodiment the multilayer component includes a ceramic main element being a varistor ceramic and at least one metal structure, wherein the metal structure is cosintered, and wherein the main element is doped with a material of the metal structure in such a way that a diffusion of the material from the metal structure into the main element during a sintering operation is reduced.

A method of forming a super hard polycrystalline construction comprises forming a liquid suspension of a first mass of nano-ceramic particles and a mass of particles or grains of super hard material having an average particle or grain size of 1 or more microns, dispersing the particles or grains in the liquid suspension to form a substantially homogeneous suspension, drying the suspension to form an admix of the nano-ceramic and super hard grains or particles, and forming a pre-sinter assembly comprising the admix. The pre-sinter assembly is then sintered to form a body of polycrystalline super hard material comprising a first fraction of super hard grains and a second fraction, the nano-ceramic particles forming the second fraction.

The super hard grains are spaced along at least a portion of the peripheral surface by one or more nano-ceramic grains, the super hard grains having a greater average grain size than that of the grains in the second fraction which have an average size of less than around 999 nm.