STRATI A SBALZO NONCHE'PROCEDIMENTO PER PRODURRE STRATI A SBALZO SPECIALMENTE PER SENSORI DIMOTORI ENDOTERMICI

A free-standing, self-supporting layer of glass-ceramic or crystallized glass is applied by thick-film technology over a presintered layer made of a vaporizable or etchable material which, after sintering the thick-flim glass-ceramic or crystallized glass layer (3) to a substrate (1), is removed by heating or etching. The layer (2) to be removed is preferably applied in paste form with the glass-ceramic thick-film layer (3) thereover either in form of a crossing bridge, as a partially covering cantilever, or entirely surrounding the layer 2, in which latter case the thick-film layer (3) is of porous construction so that the volatile or vaporizable components of the underlying layer (2) can escape through the thick-film layer (3). A typical layer which is volatile or vaporizable includes carbon black, a resin binder and a solvent, applied to a substrate, for example of ceramic or enameled metal, over which the glass-ceramic layer is applied. Electrically conductive tracks can be applied directly on the substrate beneath the layer (2) to be removed, and to the thick-film layer, or in the form of strain or temperature-sensitive resistors, for connection to an external circuit evaluating deformation of the free-standing layer by capacitative or resistance change, to obtain pressure sensors, vibration sensors, acceleration sensors, and the like of minute construction. A typical dimension of the thick-film layer is in the order of tens of micrometers, with the free space after removal of the filler (2) being also about in the order of tens of micrometers.