Matrix and method for its production

The matrix comprises freely flow-throughable channels for an exhaust gas of internal-combustion engines from layers of metal foil, where the metal foil is a smooth metal foil (3) and a continuously-structured metal foil (4). The continuously-structured metal foil has a primary structure in the form of shafts. The smooth metal foil or the continuously-structured metal foil is partially present in an axial direction (10). Other continuous foil comprises intersections whose mutually opposed cutting faces (6a, b) are offset from one another transverse to a main plane of the foil. The matrix comprises freely flow-throughable channels for an exhaust gas of internal-combustion engines from layers of metal foil, where the metal foil is a smooth metal foil (3) and a continuously-structured metal foil (4). The continuously-structured metal foil has a primary structure in the form of shafts. The smooth metal foil or the continuously-structured metal foil is partially present in an axial direction (10). Other continuous foil comprises intersections whose mutually opposed cutting faces (6a, b) are offset from one another transverse to a main plane of the foil. The intersections: lie in sections (7) in which no metal foil is present; and are part of a secondary structure (8), which is present in the continuous foil. The secondary structure comprises inverted sections (9) of shaft-mountains (12) with the intersections of the curved metal foil placed at one end of the inverted sections. The total inverted sections in sections are arranged away from the metal foil. The matrix consists of a corrugated metal foil, and/or the smooth metal foil in the form of strips placed in the axial direction is coiled between the layers of corrugated metal foil. The strips at its spiral inner end are welded or soldered to the other metal foil. The inverted sections in the axial direction or in a transverse direction alternately from different sides are introduced into the corrugated metal foil. A thickness (5-20%) of the metal foil is larger than the other metal foil. The inverted sections have a height of 50-80% of the height of the curved metal foil. A width of the strips is 0.4-0.6 times the distances in the axial direction between the strips. The width of the strips corresponds to 3-4 times the height of the corrugated metal foil in the finished matrix in outer regions. The thickness of the curved metal foil is 45-55 mu m. An independent claim is included for a method for producing a m