Influence of Bioactive Glass Addition on TC4 Laser Cladding Coatings: Microstructure and Electrochemical Properties

Abstract

There is a growing interest in enhancing the bioactivity of TC4-based metallic biomaterials, which are known for their excellent biocompatibility. Bioactive glass (BG) has been recognized for its high potential in promoting bioactivity, particularly in osteo tissue engineering. This study focuses on investigating the influence of BG addition on the microstructure and electrochemical properties of TC4 coatings. The TC4/BG composite coatings were fabricated through laser cladding, and their microstructure was characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The electrochemical properties of the coatings were assessed through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests in three different solutions. The results revealed that the incorporation of BG had a significant impact on the microstructure of the TC4 coatings, leading to the formation of a well-defined interface between the TC4 matrix and the BG aggregates. The distribution of BG aggregates within the TC4 matrix coating was found to be random and unrelated to the specific regions of the coating. The metallographic microstructure variations were attributed to different heat dissipation conditions during the laser cladding process. Furthermore, the electrochemical corrosion behavior of TC4/BG composite coatings reveals that they exhibit stability similar to that of passive films and good resistance against media corrosion compared to TC4, while also showing enhanced corrosion resistance in 3.5 wt% NaCl and Dulbecco’s modified Eagle medium (DMEM) solutions, indicating their potential for biomedical applications; however, the corrosion resistance decreases gradually in all solutions, potentially due to the elevated Cl− concentration. Further research can explore bioactivity enhancement of TC4/BG composite coatings and investigate the long-term stability and biological response of these coatings in diverse physiological environments.