Iron oxides possess good hardness and is it possible that these oxides help in reduction of friction at 500 degree celcius
Fe3O4 (Magnetite) has been observed to occur in fretting (tribology) tests at high temperature (450 Celsius). It was tribo-sintered on the contacting steel surfaces.
So this could happen as well at 500 Celsius. It is a self-forming solid lubricant. It occurs in high temperature fretting in air. The mechanism is a mix of tribology fretting and oxidation.
Thanks Mir and Julius
Actually I came across a book where it was mentioned that around 400-500 celcius, Fe2O3 is majorly formed which is the hardest amongst other oxides and abrasive too, so in that case it wont reduce friction.
I am just confirming it as in some of the cases where you are using some sintered iron base composition which is subjected to certain wear test, there rise in friction may be related to hard oxides. Because due to the absence of XRD test facility, literature or previous research can be quoted for justification.
Still if some one else throw more light over it, I would be thankful
Please, read my work: The effect of temperature on wear and friction of a high strength steel in fretting
Julius Abere · S.R. Pearson · P.H. Shipway · J.O. Abere · R.A.A. Hewitt
Fe2O3 falls off as wear particles, while Fe3O4 builds up in the tribo-contact and self-heal worn surfaces and lubricate.
Thanks Julius
Am glad that you reponded. Now My doubt is clear and thats Fe2O3 enhances wear and friction.Have already read your paper.
Thanks again
Iron oxides as a layer on an iron surface can protect (in small range) against wear. However the powder of iron oxides can not be a good lubricant because of their hardness. I've done the research with nano and micro powders of iron oxides dissipated in oil base, and always the wear results were worse than for pure oil.
Im working with steel hot forging processes, and the Fe oxides are a big problem because it high hardness. Normally are bigger than hardness of die material, wear faster the die cavities, while the first forging operation is an upsetting to remove the scale. For this reasons, I think that this product is not good for using like solid lubricant.
Dear Krahmer,
Thanks for responding
Yes krahmer, actually I have used some solid lubricant with Fe base material, and in ceratin compositions wear rate was and friction was high inspite of raised percentage of solid lubriccant. Hence I concluded that oxides being harder than my developed composite which was having max Vickers hardness as 130, high friction and wear amounts to presence of oxides whether it is Fe2O3 or Fe3O4.
What do you say?
Dear kramer,
Can you refer me to certain atricles or your article where it is mentioned that oxides result in wear and friction
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