We are pleased to announce the delivery of the Oscillation Sliding Tester OST3000, a reciprocating sliding-type adhesion strength testing system manufactured by Rhesca Corporation, on June 19.

Evaluation of Interfacial Failure Induced by Fatigue Wear

Compared with scratch testing, conventional friction and wear tests provide a more realistic approach to evaluating the durability of hard coatings under conditions closer to those encountered in actual applications. However, the number of sliding cycles required to induce failure can vary significantly depending on the applied load, making it difficult to determine appropriate test conditions and potentially resulting in lengthy evaluation times. The OST3000 enables load-increasing sliding tests, in which the applied load is continuously increased during sliding. This allows us to evaluate the progression of fatigue wear and interfacial delamination in hard coatings, including DLC (Diamond-Like Carbon) coatings, and to efficiently assess their interfacial strength.

Automated Observation of Wear Scars

The OST3000 is equipped with a function that enables the wear condition of both the specimen and the indenter to be observed at arbitrary points during the sliding test. By observing wear scars during testing, the progression of wear and the failure process of the coating can be tracked over time. By correlating the observed wear images acquired at different stages of the test with the applied load and friction force (coefficient of friction), the system can be used to investigate the causes of changes in friction and to identify the initiation sites of coating failure and delamination. The standard configuration includes a CCD camera for observing wear scars on both the specimen and the indenter. Additional observation instruments, such as an AFM or white-light interferometer, can also be integrated into the system. The instrument is equipped with a rail mechanism that enables movement between the sliding test position and the observation position. By defining the positional relationship between these two locations on the PC, the system can automatically switch between testing and observation. This enables the progression of wear and failure to be tracked in situ by repeatedly performing sliding tests and wear-scar observations.

The OST3000 was jointly introduced as part of a collaborative research project with the Komatsu Collaborative Research Cluster for Innovative Technologies, with which our laboratory conducts joint research. We will utilize this system to evaluate the interfacial strength and wear resistance of hard coatings, including DLC, and to elucidate their tribological behavior under conditions representative of practical applications.