*Article* **Influence of Slide Burnishing Parameters on the Surface Layer Properties of Stainless Steel and Mean Positron Lifetime**

**Agnieszka Skoczylas 1,\*, Kazimierz Zaleski 1, Jakub Matuszak 1, Krzysztof Cieciel ˛ag 1, Radosław Zaleski <sup>2</sup> and Marek Gorgol <sup>2</sup>**


**Abstract:** This paper presents the results of an experimental study on the impact of slide burnishing on surface roughness parameters (*Sa*, *Sz*, *Sp*, *Sv*, *Ssk*, and *Sku*), topography, surface layer microhardness, residual stress, and mean positron lifetime (*τmea*n). In the study, specimens of X6CrNiTi18 stainless steel were subjected to slide burnishing. The experimental variables were feed and slide burnishing force. The slide burnishing process led to changes in the surface structure and residual stress distribution and increased the surface layer microhardness. After slide burnishing, the analyzed roughness parameters decreased compared with their pre-treatment (grinding) values. The slide burnishing of X6CrNiTi18 steel specimens increased their degree of strengthening *e* from 8.77% to 42.74%, while the hardened layer thickness *gh* increased after the treatment from about 10 μm to 100 μm. The maximum compressive residual stress was about 450 MPa, and the maximum depth of compressive residual stresses was *gσ* = 1.1 mm. The positron mean lifetime *τmean* slightly yet systematically increased with the increase in burnishing force *F*, while an increase in feed led to changes of a different nature.

**Keywords:** slide burnishing; X6CrNiTi18 stainless steel; surface roughness 3D; topography; microhardness; residual stress; positron mean lifetime *τmean*
