What are the main risks of under- or over-treatment ?

A under-treatment can only be genrerated by a stop of the machine (due to a emergency or failure detection). This under-treatment leads to a bad adhesion behaviour. The part can be retreated.

Over-treatment can occur due to a over exposure to the treatment gas, wich is impossible with automatic machines but can occur by a human error. But, even in the case that operator would treat 3 times, the surface modification are far enough of a surface degradation (depend of the treated material)

Is there any specification on the substrate holder materials ?

There is a few material to avoid ; Stainless steel, cellulosic material such ase wood, strong paper ... The process is also compatible with cast iron.

What is the gas composition ?

This aspect is confidential but the treatment gas willl always be a mixture of N2+O2.

Price of the gas ? Expected evolution of the gas price ?

For nitrogen : Nitrogen is obtained by a cryogenic distillation of air. Rough material is cheap but energy cost can be indexed on electricity cost.

For oxygen : the production process of oxygen implies adsorption of atmospheric nitrogen on a molecular sieve. As nitrogen , variation of kWh price would affect the oxygen price