Regulating the CVD diamond coating stress by the VO2 stress regulation layer

Abstract

During cutting operations, localized heating at the interface between the tool and the coating leads to internal stress increment, which exacerbates the potential for delamination or cracking of the coating. In the present study, a novel approach is proposed to alleviate the stress within the CVD diamond coating by employing a VO2 stress regulation layer. The paper investigates the variation pattern of stress and adhesion within the VO2 stress regulation layer/CVD diamond coating under thermal loading conditions. The findings indicate that the stress within the VO2 stress regulation layer/CVD diamond coating undergoes a sudden change as heat increases, resulting in a 33.3 % decrease in stress. Conversely, the stress within the V film/CVD diamond coating changes proportionally with the stress of the CVD diamond coating. When abrupt stress changes, the stress within the CVD diamond coating is twice that of the VO2 stress regulation layer/CVD diamond coating, while the stress within the V film/CVD diamond coating exceeds that of the VO2 stress regulation layer/CVD diamond coating by 1.5 times. Following repeated thermal loading, the VO2 stress regulation layer retains its ability to regulate the stress of the CVD diamond coating. The scratch test demonstrated a notably robust adhesion between the substrate and the coating, evidenced by a critical load surpassing 120 N post-stress regulation. By mitigating the stress within the CVD diamond coating, interface cracking can be minimized, consequently reducing instances of coating peeling.