## 3 Results and Discussion
### EDS Analysis  
After the tool life tests it was observed with the naked eye that the surface of the ion-implanted teeth of circular saw blades was contaminated with the remains of wood fibers, dust, etc. The teeth of the non-treated circular saw blades were much less dirty. After manual cleaning of the tested tools, a change in colour and a different shade of the ion-implanted tooth surface were visible (Figure 11). After these observations, a decision was made to test the surface of the teeth using a scanning electron microscope (SEM) and EDS measurements.  
At the same time, activation of the surface of the implanted saw tooth was observed, manifested by an increase in adhesion and appearance of the secondary structures on the WC-Co surface. During friction, the secondary structures are in different stages of existence and decay. In order for the wear to be stabilized and of minimum intensity, the friction should lead to the creation of a dynamic equilibrium between the removal process and the formation of these structures on the friction surface. The wear will then be mechanochemical. The secondary structures distribute pressure and friction forces, significantly extending the durability of materials in tribological contact. The secondary structures can be related to the self-organization of the friction surface and contribute to the reduction in wear and increase in tool life during cutting [28].  
Figure 12 shows the EDS analysis of elements' concentration on the surface of non-treated and ion-implanted tools after tool life tests, and the elements' concentration increase between these two groups of tools. The analysis was limited to elements having the largest share in WC-Co material, i.e., tungsten W and carbon C, while the presence of other elements with small shares was taken into account in the total under the name \"Others\". The variability ranges (\(\pm\)standard deviation) are also marked in the top bar chart.  
Figure 10: Estimated total cutting length and the relative tool life index for non-treated and ion-implanted circular saw blades.  
The EDS analysis clearly shows an over 17% increase in the share of carbon in ion-implanted tools, mainly at the expense of the share of tungsten. Changes in the share of other elements were not statistically significant. Thus, the secondary structure formed during the machining on the ion-implanted tools was mainly composed of carbon.  
Carbon produces a specific friction surface that reduces the coefficient of friction. The phenomenon transforms the dry friction mechanism into the boundary friction. The boundary friction occurs when a thin layer of lubricant separates the surfaces moving relative to each other; there is no liquid friction in the friction pair, yet the value of the friction coefficient and intensity of wear are reduced by 2-3 orders [29].  
The unresolved issue is the origin of the carbon from the friction pair of materials: the WC-Co tool or the wood-based workpiece. The first option would indicate the phenomenon of the segregation of atoms on the friction surface caused by thermodiffusion, activated by surface heating due to friction [30]. The second option may indicate the phenomenon of the selective transfer of atoms from the second material of the friction pair  
Figure 11: Tooth surfaces of circular saw blades: (**a**) non-treated tool with visible directional grinding after tool sharpening, (**b**) ion-implanted tool with poorly visible grinding obscured by a darker secondary structure.  
Figure 12: The concentration of elements on the surface of non-treated and ion-implanted tools after tool life tests and percentage increase in elements’ concentration.  
as described by [PERSON] and [PERSON] (1968) [31]. Undoubtedly, these issues will be the subject of further research by the authors.