Investigation of Surface Layer Condition of SiAlON Ceramic Inserts and Its Influence on Tool Durability When Turning Nickel-Based Superalloy

SiAlON is one of the problematic and least previously studied but prospective cutting ceramics suitable for most responsible machining tasks, such as sophisticated shapes aircraft gas turbine engine parts made chrome–nickel alloys (Inconel 718 type) with increased mechanical thermal loads (semi-finishing). Industrially produced inserts are replete numerous defects (stress concentrators). When external applied, wear pattern difficult to predict. The destruction edge, tearing out entire conglomerates, can occur at any time. complex approach additional diamond grinding, lapping, polishing combined an advanced double-layer (CrAlSi)N/DLC coating was proposed here first time minimize it. criterion failure chosen be 0.4 mm. developed tri-nitride sub-layer plays a role improving main DLC adhesion. microhardness 28 ± 2 GPa, average coefficient friction during high-temperature heating (up 800 °C) ~0.4. durability insert after polishing, 12.5 min. That superior industrial those subjected by 1.8 1.25 times, respectively.