Process for manufacturing a component for an emissions treatment unit

A process for manufacturing a component for an emissions treatment unit, comprising taking a ceramic unit prepared by extruding green ceramic product through a die to form an extrusion having a honeycomb substrate structure having an array of parallel, linear tubular cells extending along the extrusion, the cells bounded by walls dividing adjacent cells from one another, the ceramic unit being obtained by cutting off, curing and firing a length of the extrusion, the process further comprising, following the firing, injecting a mixture of a flowable, uncured curable material and a particulate metal component from an end of the ceramic unit into selected ones of the cells so as to block the selected cells over at least a part of the lengths thereof while maintaining all of the walls of the ceramic unit, and curing the injected mixture to render the injected mixture solid.