MATERIALS
Structure, phase composition and tribological properties of iron-based composites in situ synthesized from powdered Fe-high-carbon ferrochrome mixtures
The article presents the results of investigations of tribotechnical properties of powder composite materials based on the ironhigh-carbon (ФХ800) ferrochrome system during dry friction with ШХ15 steel at various loads of 30, 60, and 100 N. It was found that an increase of the load from 30 to 100 N leads to an increase in the coefficient of friction from 0,45 to 0,5 (for 25% ФХ800) and from 0,40 to 0,46 (for 40% ФХ800). At the same time, the mass wear of samples made of powder materials decreases with an increase in ФХ800 content from 25 to 40 (wt. %) and with growth of the load from 30 to 100 N, respectively, from 3,5 – 8,0 to 0,75 – 1,6 mg/km., which provides wear resistance improvement (km/mm) by 2,8 – 2,2 times. X-ray phase full profile analysis using the Rietveld method established that there are 2 phases: metallic α-Fe (79,68%) and carbide Me7C3 (20,32%) in the composite Fe – 25%ФХ800 and 3 phases: α-Fe (69,5%), γ-Fe (3,96%) and carbide Me7C3 (26,57%) in the Fe – 40% ФХ800 composite. Topographic studies of 2D profiles of worn surfaces of composites after friction under different loads were conducted. The results of optical profilometry show that the main mechanism of destruction of the powder composite surface during dry friction with ШХ15 steel is adhesive wear (seizing) of the contacting surfaces.