Study On Microstructure And Properties Of Supersonic Plasma Sprayed FeCrMoBCY Amorphous Coating

Amorphous alloy are highly promising materials in engineering application for its ultrahigh hardness and strength,superior corrosion-resistance and wear-resistances.Amorphous metallic coatings fabricated by thermal spray technology are more promising and significant,and carried forward the superiority in hardness,wear and corrosion resistance.Fe-based amorphous metallic coatings with a nominal composition of Fe₄₈Cr₁₅Mo₁₄B₆C₁₅Y₂ were fabricated by supersonic plasma spraying?SPS?in this article.The effect of spraying power and Ar flow rate on the in-flight behavior and splat spreading behavior of Fe-based amorphous droplets was investigated.The microstructure and tribological properties of coatings were respectively experimented and analysed by lots of equipments and methods.The results showed that:?1?With the increase of spraying power,the velocity of particles and the surface temperature increase gradually.With the increase of Ar flow rate,the surface temperature increases and then decrease.And under the spraying power of 60 kW and the Ar flow rate of 110-L/min,the melt index reaches best state.The spreading morphologies of droplets show the disc type.?2?Fe-based amorphous metallic coatings primarily consist of amorphous phases,which was caused by the high glass forming ability of the alloy system and the high cooling rate of the SPS technology,as well as the unique intermittent spraying process adopted in this study.In addition,the coatings exhibit high thermal stability below the high crystallization temperature of 963 K,which is few affected by the spraying parameters.?3?The amorphous content and microhardness initially increases and then declines gradually with the increase of Ar flow rate and spraying power whereas the porosity decreases firstly and then increases.And it keeps consistent with the changes of micro-hardness however the porosity on the contrary.The amorphous content and the microhardness of coating A5 can be reached 96.78%and 1005 HV_0.1 respectively,whereas the porosity is only 0.85%.The disc type is helpful for the overlap of spreading droplets and improving the coating quality.?4?Under the same dry friction condition,the friction coefficients of Fe₄₈Cr₁₅Mo₁₄C₁₅B₆Y₂ amorphous coating under different spraying parameters do-not differ greatly.With the increase of the spraying power and argon flow rate,the wear rate of the coating decreases firstly and then increases.With the increase of frequency,the friction coefficient decreases gradually,but the wear rate increases;with the increase of applied load,the friction coefficient of the coatings increases,the wear rate increases.From the slope analysis of the wear rate of the coating,it was found that the Fe₄₈Cr₁₅Mo₁₄C₁₅B₆Y₂coating is more sensitive to the sliding frequency.?5?The worn-surface morphologies of the examined coatings demonstrate that coating wear mechanism is a combination of abrasive and oxidative wear.In addition,delamination wear may occur.The main wear mechanism of the substrate is adhere wear.