Abstract: A process and apparatus for case hardening of ferrous metal work pieces is described in which the work pieces to be processed are placed inside a metal vacuum chamber which is evacuated with a mechanical pump and then backfilled with a partial pressure of a gas containing nitrogen, such as nitrogen or ammonia, or a hydrocarbon such as methane, or mixtures thereof. The work pieces to be processed are electrically connected to the negative (cathode) terminal of a D.C. power supply, the positive terminal being connected to the chamber wall and to ground. The power supply is energized and some of the gas is converted to ions. The work pieces are heated to temperatures of approximately 650.degree. to 1100.degree. F for ionitriding or to temperatures of approximately 1650.degree. to 1900.degree. for ion carburizing. The heating is effected at least in part by the ion activity.

Abstract: An apparatus for making a laminated board having a foam plastic core between adhered sheets has limiting means for inhibiting escape of the foam plastic core outwardly of the sheets.