Microns for

Claim 1

A PROCESS FOR PROVIDING A METAL CONTAINING SUBSTRATE WITH A DIFFUSED AND CONTINUOUS CASING OF A MATERIAL SELECTED FROM THE GROUP CONSISTING OF CHROMIUM, SILICON, BORON, MANGANESE, NICKEL, BERYLLIUM, TITANIUM AND PULLADIUM WHICH COMPRISES INTRODUCING INTO A CASING ZONE THE METAL SUBSTRATE TO BE TREATED, INTRODUCING INTO A VAPORIZING ZONE A SOURCE OF CASING MATERIAL SAID SOURCE OF CASING MATERIAL BEING SPACED AWAY FROM SAID SUBSTRATE, HEATING SAID SOURCE OF CASING MATERIAL OF A REDUCED PRESSURE TO AN ELEVATED TEMPERATURE TO PRODUCE VAPOR OF SAID CASING MATERIAL, THE ATOMS OF WHICH VAPOR HAVE SUFFICIENT ENERGY TO TRAVERSE THE DISTANT BETWEEN SAID SUBSTRATE AND SAID SOURCE OF SAID CASING MATERIAL, THE TEMPERATURE OF SAID VAPOR BEING AT LEAST THAT AT WHICH SAID SUBSTRATE AND SAID CASING MATERIAL EXHIBIT SUBSTANTIAL MUTUAL AFFINITY; HEARING SAID SUBSTRATE IN SAID CASING ZONE UNDER A REDUCED PRESSURE NOT EXCEEDING THE PRESSURE IN SAID VAPORIZING ZONE AT LEAST TO A TEMPERATURE OF WHICH SAID SUBSTRATE AND SAID CASING MATERIAL EXHIBITS SUBSTANTIAL MUTUAL AFFINITY BUT BELOW THE TEMPERATURE OF WHICH SAID SUBSTRATE MELTS AND BELOW THE TEMPERATURE AT WHICH THE VAPOR PRESSURE OF ABSORBED CASING MATERIAL AT THE SURFACE OF SAID SUBSTRATE IS EQUAL TO THE VAPOR PRESSURE OF THE CASING MATERIAL AT THE TEMPERATURE OF SAID VAPOR OF SAID CASING MATERIAL; INTIMATELY CONTACTING SAID SUBSTRATE WITH SAID CASING MATERIAL VAPOR, AND MAINTAINING SAID SUBSTRATE IN INTIMATE CONTACT WITH SAID CASING MATERIAL VAPOR UNTIL THE MATERIAL VAPOR HAS DIFFUSED INTO SAID SUBSTRATE TO A PREDETERMINED DEPTH.