Fig. 8. The scheme of the surface layer structure of friction graphitized grey-iron (steel), taking into account the alloying influence:  1 – lubricated material; 2 – boundary layer; 3 – secondary structures; 4 – carbides and sulphides have increased the surface hardness; 5 – phosphides  introduced into the composition of the secondary structures; 6 – graphite has decrease the specific pressure of contacted surfaces; 7 – products of interaction (Beilby layer, oxides layer); 8 – textured layer; 9 – deformed layer; 10 – metal base (initial metal structure); 11 – strengthening of carbides (а) and phosphides (b) and eutectic due to influence of carbide- forming elements; 12 – strengthening of structure due to VC, TiC types of carbides; 13 –influence of graphite phase on the parameters; 14 – strengthening of the metal matrix due to alloying elements; 15 – appearance of other structural components (martensite, ferrite etc.); 16 – appearance of optimal microstructures on the wear surfaces; 17 – intercalated properties of graphite and others layered compounds; 18 – influence of hydrogen on the lubricated and lubricated–cooled  materials; 19 – introducing of hydrogen and oxygen to the composition of the secondary structures.

Fig. 9. Character of  material separation  from the surface of friction × 35 (a); ×. 100 (b).

The viscous matrix is capable of  keeping carbides, which  can be rubbed into a fragile metal matrix during friction [27]. The results of X-ray structural analysis and authors’ research as well as  literary data prove that during friction in a thin working surface  layer the allocation of low dispersion carbides takes place [28]. The viscous metal matrix that contains proportionally spread  low dispersion of carbides proves the Charpy principle [23] that promotes the increase of wear resistance.

It is natural that the topography of friction surface  and undersurface layers essentially depends on the initial cast structure.  Figure 10а displays an image of friction surface of austenitic cast-iron, formed during normal  friction mode (without seizure). Figure  10b depicts  layers adjoining  the zone of friction (the left part of the image).