# The Effect of Particle Type and Size on CoCr Surface Properties by Fine-Particle Shot Peaning
## 5 Conclusions  
The study investigated the effect of particle type and size on the surface properties of a CoCr alloy, including surface morphology, surface roughness, and surface hardness, by using the fine-particle shot peening technique. The results indicated that the use of different types and sizes of peening media, such as silica and ceramic particles, can significantly alter the surface morphology of the CoCr alloy, inducing features such as surface roughness, texture, and defects. The study also showed that the surface roughness and hardness of the CoCr alloy can be improved by optimizing the peening parameters such as the peening pressure and duration. Furthermore, the Micro Vickers hardness test revealed that the CoCr alloy's surface hardness increased significantly after fine-particle shot peening, indicating the potential of this technique for enhancing the material's mechanical properties. Overall, the findings suggest that the fine-particle shot peening technique can be an effective surface-treatment method for improving the performance and durability of the CoCr alloy and other metallic materials in various engineering applications. Further research can explore the effect of different process parameters and peening media on the CoCr alloy's surface properties and investigate the underlying mechanisms of the peening-induced changes in the material microstructure and properties.  
Optimizing these parameters can lead to desirable surface properties such as improved hardness, wear resistance, and fatigue life. The authors have conducted a series of experiments varying these parameters to identify the most favorable process conditions for their specific application. In summary, the most favorable process conditions for fine-particle shot peening of the CoCr alloy can vary depending on the specific goals and constraints of the study. It is essential to conduct systematic experiments to identify the optimal process conditions for a particular application.  
Therefore, the surface properties of the CoCr alloy can be improved by the fine-particle shot peening process in optimized conditions. The higher-hardness particle can change the surface properties more than the lower one, and the larger particle size can change the surface properties more than the smaller particle size. The results prove that the fine-particle shot peening process can change the surface microstructure and improve the surface properties of CoCr. For future direction, the fine-particle shot peening process may be the process of choice for improving the surface properties of medical implants such as dental implants or orthopedics implants (the bearing surface of the total hip replacement), which can increase the strength and reduce the wear process, resulting in increasing the longevity of the implant.  
All authors conceptualized and designed the study. [PERSON] and [PERSON] performed data collection and prepared the manuscript draft; [PERSON] and [PERSON]-n. helped critically revise the manuscript for important intellectual content. All authors have read and agreed to the published version of the manuscript.  
This research and innovation activity is funded by National Research Council of Thailand (NRCT).  
Not applicable.  
The original contributions presented in the study are included in the article. Further inquiries can be directed to the corresponding author.  
Thailand Science Research and Innovation (TSRI) Basic Research Fund: Fiscal year 2023 under project number FRB660073/0164. National Research Council Thailand (NRCT).  
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.