The heat treatment process is employed with both chemical nickel and hard chromium process technologies. Heat treatment serves as a preventative measure for the resistance of high-strength steel parts against hydrogen-induced brittle fractures in accordance with DIN 50969 (colloquially put - hydrogen diffusion annealing). Directly after nickel or chromium plating, the parts are placed in a furnace (between 120°C - 400°C) for dehydrogenation. Through appropriate heat treatment, it is possible to extract the hydrogen absorbed during the coating process. The surface characteristics exhibit very little change. It is necessary to note here, that an increasing coating thickness also means an increase in the gas-tightness of the coating.
With the heat treatment of parts that are chemically nickel plated, there is an improvement in the coating adhesion on various base materials and this takes place with the application of temperatures between 120°C and 400°C.
A further advantage of heat treatment is the increase in hardness of the chemical-nickel coating. Nickel-phosphorus coatings have a hardness of 550 (± 50) HV in the deposited state. With the help of heat treatment from approx. 290°C it is possible to increase the hardness to around 1000 (±50) HV.
Avoidance of hydrogen embrittlement