Hi, Question here quite specific so I will try to broaden the topic. What I am curious with is if anyone knows any other metals that are corrosion irresistant to zinc dithiophosphate hydraulic oils. What I know is cuprum/zinc 60/40. What is more specific if anyone good petrochemist to explain why exactly that happens as chemical reaction.Furhtermore, if anyone with the bad experience with the Hitachi machinery that is built form yellow metal which year is it manufactured ( I am asking cause we have a Hitachi wheel loader) Maybe thats it at the moment )
Hmm, a bit of a confusing question, so are you interested in the chemical reaction as zddp breaks down? generally zddp coats and clings to the metal parts to help provide wear resistance and cut down on friction when lubrication fails.
I am interested in both reaction with zinc containing metals where it is corrosive and also in others where it coats and provides wear resistance. 2. Besides zinc/cuprum alloys what other metals is zddp acting not as a protectant but is corrosively active. ( hope that clarifies)
As far as zddp in oils, it works by lingering in the oils and when the oil film fails, the zddp is smeared between the two impacting surfaces acting as a buffer and getting pressed into the metal surfaces when they rub. A last line of defense when you loose the hydrodynamic wedge of oil film Metals more reactive than zinc would be aluminum and magnesium, then you'd have the alkali metals calcium sodium and potassium.
Would you suggest though when manganese is more reactive than zinc that zddp containing oils should also not be used in manganese alloys. I know that better quality crushers are made with aboud 20-25% manganese alloy or maybe this is only specific parts that need to be extra wear resistant like hammers , jaws etc.
Manganese (Mn) is down there in reactivity with chromium and less than steel, Magnesium (Mg) is very nicely reactive and can even burn like the dickens. Magnesium is sometimes alloyed with aluminum to reduce its reactivity.