## 1 Introduction  
Thermal spray coatings are characterized by a heterogeneous microstructure comprised of oxides, pores, and cracks due to the deposition process and the chosen thermal and kinetic parameters of the applied thermal spray process. Furthermore, the mentioned imperfections result in increased surface roughness. While open porosity is a disadvantage in corrosion prevention applications, in tribological systems, it can improve the emergency running properties by acting as an oil reservoir [1; 2; 3]. In order to achieve a suitable surface topography of thermal spray coatings in tribological systems, finish machining is necessary. Hence, for the desired open porosity, lubrication and contamination effects must be avoided during machining. Finishing of thermal spray coatings using tools with geometrically defined cutting edges is often limited due to the constitution of the deposited layer. Hard abrasive particles such as oxides and carbides, as well as the coating porosity resulting from the spraying process, cause rapid cutting tool wear [4; 5; 6; 7; 8; 9; 10]. Another problem is the comparably low coating adherence to the substrate. Hence, the selection of the cutting material and the adjustment of the machining parameters to the coating microstructure are essential to achieve the targeted surface properties. In finish boring experiments of iron-based thermal spray coatings, the influence of the cutting material on the tool wear was analyzed [4; 5]. Of the indexable inserts used, two were CBN-tipped (high and low content of boron nitride, respectively), one diamond-tipped, one was cermet, and one was cemented carbide. Machining was performed with constant cutting parameters (\(v_{c}\) = 300 m/min, \(f\) = 0.1 mm, \(a_{p}\) = 0.25 mm). After a cutting length of 390 m, the cermet tool displayed the highest tool wear, with a measured flank wear land width of about 2.1 mm. Using CBN with 50% boron nitride bounded by a ceramic binder, diamond, or cemented carbide as the cutting material resulted in similar flank wear land widths of about 1 mm. Significantly lower tool wear (flank wear land width of 0.1 mm) was achieved by finish boring with CBN-tipped tools with 90% boron nitride and a metallic binder. [PERSON] et al. focused on the adjustment of the cutting parameters while turning iron-based thermal spray coatings [6; 10; 11]. The cutting parameters, particularly the cutting speed, have a significant influence on the quantity of pulled-out coating material. This effect results in the generation of a high oil retention volume. Experimental investigations addressed the influence of the cutting speed in turning of Fe17 Cr2 Ni0.2C coatings produced by atmospheric plasma spraying. CBN-tipped indexable inserts having a high content of boron nitride and a metallic binder were used. During the experimental investigation, the cutting speed \(v_{c}\) was adjusted while being kept within a range of 100 m/min to 400 m/min. Feed \(f\) (0.05 mm) and depth of cut \(a_{p}\) (0.05 mm) were kept unchanged during dry machining. After turning, the surfaces were generally characterized by feed marks, pores, microcracks, and a high valley void volume due to pulled-out coating material. These findings corroborate the results represented in [5; 6; 7]. Increasing the cutting speed caused a decreased proportion of pulled-out coating material and subsequently lower surface roughness values due to the higher shear zone temperature. However, the simultaneous increase in tool wear resulted in minimal values for \(Ra\) and \(Rz\) after machining with a cutting speed of \(v_{c}\) of 300 m/min. These results were confirmed in experimental investigation of the turning of Ni5 Al thermal spray coatings by varying cutting speeds \(v_{c}\) (30 m/min-260 m/min), depths of cut \(a_{p}\) (0.05 mm, 0.12 mm), and feeds \(f\) (0.05 mm-0.2 mm) [8]. In addition to the cutting speed, the feed also influences the surface properties in the machining of sprayed coatings. A higher feed results in increased kinematic surface roughness.