There are several methods of nitriding available, the first to be developed and still the industrial leader is gas nitriding. The gas nitriding process consists of heating the components in a furnace with a retort in which air has been replaced with ammonia gas. The process is controlled by monitoring the dissociation of the ammonia gas and controlling the gas flow and process temperature and time. A dissociation burette is used for this, on the basis that the undissociated ammonia gas in a sample of the furnace atmosphere can be dissolved in water and hence give a measure of the volume of atomic nitrogen available for nitriding. It is also now possible to monitor and control the process using a modified infra red gas analysis method, similar to that used in gas carburising control.
There are several methods of nitriding available, the first to be developed and still the industrial leader is gas nitriding. The gas nitriding process consists of heating the components in a furnace with a retort in which air has been replaced with ammonia gas. The process is controlled by monitoring the dissociation of the ammonia gas and controlling the gas flow and process temperature and time. A dissociation burette is used for this, on the basis that the undissociated ammonia gas in a sample of the furnace atmosphere can be dissolved in water and hence give a measure of the volume of atomic nitrogen available for nitriding. It is also now possible to monitor and control the process using a modified infra red gas analysis method, similar to that used in gas carburising control.
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