The invention relates to a novel method for carrying out low-temperature surface
catalysis and
nitriding on
alloy cast iron, belongs to the technical field of the
surface chemical heat treatment application of
metal materials and is suitable for low-temperature and rapid surface
nitrogen treatment (in the strengthening
nitriding process, the temperature is less than 480 DEG C and the time is less than 10 hours; and in the
corrosion-resisting
nitriding process, the temperature is between 500 and 520 DEG C and the time is less than 4 hours) of an
alloy cast iron cylinder sleeve and an
alloy cast iron piston ring. Based on the surface
catalysis theory, the invention designs an active catalyst component, utilizes an adjustable bidirectional
pulse power supply to form a catalytic film, i.e. a surface catalyst, on the surface of the alloy cast iron, improves the activity that the
metal surface carries out
catalytic decomposition on
ammonia at the low temperature and also effectively adsorbs the decomposed free
nitrogen to form a
nitrogen adsorption layer. Moreover, the catalyst can permeate into a substrate to form
solid solution so as to promote the
diffusion rate of nitrogen. Compared with the conventional gas nitriding method, the process increases a working procedure of adjustable bidirectional pulse surface deposition treatment. The working procedure has the advantages of stable conditioning fluid and short
processing time. The novel process is suitable for the existing gas nitriding equipment.