In the bustling labs of the Surface Engineering Design Laboratory at Shibaura Institute of Technology, Ota-City, Tokyo, a groundbreaking study led by Tatsuhiko Aizawa is turning heads in the construction and energy sectors. The research, published in ‘Academia Materials Science’, delves into the fascinating world of CoCrMo alloys, a material already renowned for its toughness and corrosion resistance.
Aizawa and his team have pioneered a novel plasma nitriding technique, subjecting CoCrMo alloys to a massive nitrogen supersaturation process. The results? A homogenous nitrided layer that’s not only 12 μm thick but also boasts an expanded γ-phase with fine CrN precipitates. “This nitrogen-supersaturated layer has an average nitrogen content of 5 mass% toward the nitriding front end,” Aizawa explains, his voice brimming with excitement. “It’s a game-changer in terms of material science and engineering.”
The implications for the energy sector are particularly noteworthy. The nitrided CoCrMo alloy matrix, with its average grain size of 20 μm, has been plastically strained by the nitrogen supersaturation. This strain significantly modifies the original crystallographic microstructure, resulting in a layer of intensely textured grains with the orientation of (111) in the normal direction. “This textured layer is incredibly hard, with a hardness of 1,620 HV1N, compared to the original polycrystalline CoCrMo matrix’s 400 HV1N,” Aizawa elaborates. “It’s a remarkable improvement in mechanical properties.”
But the benefits don’t stop at hardness. The nitrided layer also exhibits a lower average friction coefficient of 0.4–0.5 against the SUJ2 ball in dry conditions, under an applied load of 5 N and a sliding speed of 0.1 m/s. This enhanced tribological performance could revolutionize the durability and efficiency of components in the energy sector, from turbines to pipelines.
The potential commercial impacts are vast. This research could pave the way for more robust and efficient energy infrastructure, reducing maintenance costs and extending the lifespan of critical components. As the energy sector continues to evolve, the demand for materials that can withstand extreme conditions and maintain high performance is only set to increase. Aizawa’s work offers a tantalizing glimpse into a future where materials like CoCrMo alloys could play a pivotal role in shaping the energy landscape.
The study, published in ‘Academia Materials Science’, is a testament to the groundbreaking work being done at the Surface Engineering Design Laboratory. As the energy sector continues to seek innovative solutions to its challenges, research like this could well be the key to unlocking a more efficient and durable future.