The effect of laser pre-oxidation of stainless steel on joining to polyamide by the LAMP method

Among the factors affecting the efficiency of laser-assisted metal and polymer (LAMP) joints, the surface condition of the joint components is one of the most important ones. So, the present study explored the effect of laser pre-oxidation of stainless steel 304 (SS304), as a novel pretreatment method, on SS304/polyamide 6 joint strength. The assessments revealed that in spite of the potential of surface pre-oxidation of SS304 for improving joint strength, the strength of the joint was reduced by ∼ 25 % in practice because, firstly, the wettability of the metal by the polymer was reduced due to the reduction of heat transfer by the metal in the preoxidized zone and secondly, the oxide layer formed on SS304 surface had a weak adherence due to the kinetic presence of Fe2O3. Hence, when using pre-oxidation, it is necessary to consider the nature of the oxide layer on the metal surface and the optimal variables of the joining process for the new conditions to achieve appropriate strength.