... for the solder to pull back is influenced by the oxygen level. Wetting and spread of the solder on the lands are then an essential factor. All the proven benefits of a low O₂ level are not worth the money spent on nitrogen if the consumption necessary to obtain the properly controlled O₂...

...M. Nowotarski; R. De Wilde ** The effects of oxygen on solder surface tension, wetting time and surface damping are presented. Oxygen levels greater than 10 ppm lower surface tension, increase wetting time and increase surface damping. Decreased surface tension leads to higher misalignment defects...