4. Description of an ammonia-rich carbonitriding atmosphere

HN carbonitriding, like standard carbonitriding (% NH ₃ < 3% by vol. generally for structural steels), is carried out in conventional carburizing furnaces of widely varying technologies: N ₂ /CH ₃ OH process, endothermic gas, in situ alkane cracking. The atmosphere will be governed by the main "equilibrium" reactions: ammonia dissociation, the nitriding reaction and carburizing reactions; to these will be added additional secondary reactions (figure 12 ).