Abstract: This invention relates to electrolytic reduction cells for aluminum production wherein tiles have been placed upon the cathode surfaces to improve the cell operation. These tiles have aluminum-wettable surfaces, which reduce electrical losses and increase cathode life. The tiles are produced from a mixture of refractory hard metal (RHM), a thermosetting resin, carbonaceous fillers and carbonaceous additives. The tiles are physically formed, polymerized and/or cross linked, and carbonized to form a tile which can be inserted into a cell. The tile may have the RHM homogeneously dispersed throughout the tile structure, or it may have the RHM concentrated in layered form.

Abstract: A process for forming a delineated vapor deposition film of a deposition material on a substrate. The delineation is accomplished by exposing selected areas of the substrate to an electron beam before depositing the deposition material whereby the sticking coefficients of the selected areas are sufficiently reduced so as to prevent any significant deposition in those areas. Furthermore, irradiated areas of the substrate can be restored to their original surface characteristics by exposure to a second electron beam while the substrate is at an elevated temperature. Thus, areas of the substrate can be negatively delineated to prevent deposition, and such negatively delineated surfaces can then be positively delineated to permit deposition.