Patent ID: 6086741
Filing Date: 2000-07-11
Classification: C25D

Abstract:
A process for sulfurizing treatment of ferrous articles by immersing articles having iron or iron alloy surfaces in a molten-salt bath of potassium thiocyanate and sodium thiocyanate contained in an electrolysis crucible and conducting electrolysis using the ferrous surfaces of the articles as anodes while maintaining a prescribed bath temperature, the process comprising:a step of positioning adjacent to the electrolysis crucible a separate pretreatment crucible containing a molten-salt bath of substantially the same composition as said bath,a step of assembling a unitary body by setting a plurality of the articles on a conductive support member in electrical contact therewith and attaching a cathode material to the support member to be out of contact with the articles and electrically insulated from the support member,a step of immersing the unitary body in the bath contained in the pretreatment crucible, maintaining this bath temperature at substantially the prescribed bath temperature during electrolysis to bring the temperature of the unitary body substantially to the prescribed temperature and transferring the unitary body from the pretreatment crucible to the bath in the electrolysis crucible while maintaining its temperature, anda step of applying a negative voltage to the cathode material and a positive voltage to the conductive support member of the unitary body in the bath contained in the electrolysis crucible, thereby treating the articles by electrolysis.