Patent ID: 6964712

Claim:
A process for treating a portion of a surface of a metal substrate, by carburization, nitrocarburization and nitriding, comprising applying to a different portion of the surface of the metal substrate, a composition which is in liquid, semi-liquid or paste form and comprises a source of boron which forms boron glass, during said treating; a magnesium-silicon compound selected from the group consisting of magnesium orthosilicate (Mg 2 SiO 4 ), magnesium metasilicate (MgSiO 3 ), and magnesium trisilicate (Mg 2 Si 3 O 8 ), wherein the source of boron glass and the magnesium-silicate compound are present in a weight ratio of 2:1 to 100:1, and wherein the magnesium silicon compound reduces the vapor pressure of boron and wherein the boron glass is soluble in water.