RESUMO
Applying ultrasound to the electroplating process can improve mechanical properties and surface roughness of the coating. Supercritical electroplating process can refine grain to improve the surface roughness and hardness. However, so far there is no research combining the above two processes to explore its effect on the coating. This study aims to use ultrasound (42kHz) in supercritical CO2 (SC-CO2) electroplating process to investigate the effect of ultrasonic powers and supercritical pressures on the properties of copper films. From the results it was clear that higher ultrasonic irradiation resulted in higher current efficiency, grain refinement, higher hardness, better surface roughness and higher internal stress. SEM was also presented to verify the correctness of the measured data. The optimal parameters were set to obtain the deposit at pressure of 2000psi and ultrasonic irradiation of 0.157W/cm3. Compared with SC-CO2 electroplating process, the current efficiency can be increased from 77.57% to 93.4%, the grain size decreases from 24.34nm to 22.45nm, the hardness increases from 92.87Hv to 174.18Hv, and the surface roughness decreases from 0.83µm to 0.28µm. Therefore, this study has successfully integrated advantages of ultrasound and SC-CO2 electroplating, and proved that applied ultrasound to SC-CO2 electroplating process can significantly improve the mechanical properties of the coating.
RESUMO
The study developed two models of an innovative high-speed lancing device and safety lancet, where the specially designed structure causes high-speed motion of the lancet, resulting in only one puncture of the skin. The two experimental models and other lancing devices sold on market were compared in order to: (1) measure the forces of lancets piercing animal skin by a load cell; (2) observe the wound areas caused by lancing devices under a microscope. The experimental results showed that, after using this innovative high-speed lancing device, the maximum force of a lancet piercing skin is only 1/3 of the force of conventional lancing devices, and the duration of the former under the skin is 1/6 of the latter. In addition, the wound area caused by the innovative lancing device is 20 % smaller than those of the conventional lancing devices. Usage of this innovative high-speed safety lancet shows that its maximum skin-piercing force is only 2/3 of conventional safety lancets, its duration under the skin is 1/4 of conventional safety lancets, and the wound area is 12 % smaller. In conclusion, both the innovative high-speed lancing device and safety lancet are proved effective in alleviating pain for diabetics and shortening the recovering time for wounds, thus, providing a more comfortable process for the self-monitoring of blood glucose.
