This copper/ceramic bonded body includes: a copper member made of copper or a copper alloy; and a ceramic member made of aluminum-containing ceramics, the copper member and the ceramic member are bonded to each other, in which, at a bonded interface between the copper member and the ceramic member, an active metal compound layer containing an active metal compound that is a compound of one or more active metals selected from Ti, Zr, Nb, and Hf is formed on a ceramic member side, and in the active metal compound layer Al and Cu are present at a grain boundary of the active metal compound.

A method for manufacturing a metal-ceramic substrate (1) includes providing a ceramic layer (10), a metal layer (20) and a solder layer (30) coating the ceramic layer (10) and/or the metal layer (20) and/or the solder layer (30) with an active metal layer (40), arranging the solder layer (30) between the ceramic layer (10) and the metal layer (20) along a stacking direction (S), forming a solder system (35) comprising the solder layer and the active metal layer (40), wherein a solder material of the solder layer (30) is free of a melting point lowering material and bonding the metal layer (20) to the ceramic layer (10) via the solder system (35) by means of an active solder process.

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.

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 copper/ceramic bonded body includes: a copper member (12) made of copper or a copper alloy; and a ceramic member (11) made of nitrogen-containing ceramics, the copper member (12) and the ceramic member (11) being bonded to each other, in which a Mg solid solution layer in which Mg is solid-soluted in a Cu matrix is formed at a bonding interface between the copper member (12) and the ceramic member (11), an active metal nitride layer (41) containing a nitride of one or more active metals selected from Ti, Zr, Nb, and Hf is formed on a ceramic member (11) side, and a thickness of the active metal nitride layer (41) is set to be in a range of 0.05 μm or more and 1.2 μm or less.

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 solder material (30) for bonding a metal layer (20) to a ceramic layer (10), in particular for forming a metal-ceramic substrate as a carrier for electrical components, comprising: a base material and an active metal, wherein the solder material (30) is a foil comprising the base material in a first layer (31) and the active metal in a second layer (32), and wherein the foil has a total thickness (GD) which is less than 50 μm, preferably less than 25 μm and particularly preferably less than 15 μm.

A copper-ceramic bonded body includes a copper member made of copper or a copper alloy, and a ceramic member made of silicon nitride, the copper member and the ceramic member being bonded to each other, in which a maximum length of a Mg—N compound phase which is present at a bonded interface between the copper member and the ceramic member is less than 100 nm, and in a unit length along the bonded interface, the number density of the Mg—N compound phase in a range of a length of 10 nm or more and less than 100 nm is less than 8 pieces/μm.

This copper/ceramic bonded body includes: a copper member made of copper or a copper alloy; and a ceramic member made of nitrogen-containing ceramics, the copper member and the ceramic member are bonded to each other, in which, between the copper member and the ceramic member, an active metal nitride layer containing nitrides of one or more active metals selected from Ti, Zr, Nb, and Hf is formed on a ceramic member side, and a Mg solid solution layer in which Mg is solid-dissolved in a Cu matrix is formed between the active metal nitride layer and the copper member, and Cu-containing particles composed of either one or both of Cu particles and compound particles of Cu and the active metal are dispersed in an interior of the active metal nitride layer.

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.