Mechanical properties of cold sintered ZnO investigated by nanoindentation and micro-pillar testing

Characteristic densification in cold sintered microstructures could also have a strong influence in defining their mechanical response. For the first time, nanoindentation and micro-pillar testing is used to study these details. Based on our recent work, we selected cold sintered (250 degrees C, similar to 99 % dense) and conventionally sintered (900 degrees C, similar to 98 % dense) ZnO samples. Hardness, elastic modulus and compressive stress of cold sintered samples were measured to be 5.5 GPa +/- 0.5, 100 GPa +/- 5 and similar to 1.2 GPa, respectively. Same values for conventionally sintered ZnO were 4.8 GPa +/- 0.6, 109 GPa +/- 6 and 0.8 GPa, respectively. The distinctive nature of grain boundary regions in cold sintered samples were found to influence the deformation behavior of these samples, as confirmed by TEM investigations. Our study reveals the potential of cold sintering and use of selected testing techniques as suitable choice.

Automated summary

The mechanical properties of cold sintered and conventionally sintered ZnO samples were compared using nanoindentation and micro-pillar testing. It was found that cold sintered samples had higher hardness but lower elastic modulus and compressive stress. Transmission electron microscopy investigations confirmed the distinctive nature of grain boundary regions in cold sintered samples that influenced their deformation behavior.