Improved passivation effect of additively manufactured WE43 porous scaffolds treated by high temperature oxidation in pure oxygen atmosphere

WE43 is a well-recognized magnesium alloy and has been successfully used in clinical biodegradable implants. High temperature oxidation (HTO) has been developed to inhibit fast degradation of WE43 alloy fabricated by laser powder bed fusion (L-PBF). This study involves constructing WE43 porous scaffolds via L-PBF, followed by HTO treatment using air (abbreviated as HTO-A) and pure oxygen (abbreviated as HTO-O) respectively. Electrochemical and immersion tests are performed to evaluate the oxidizing atmosphere's influence on degradation. Compared with HTO-A, HTO-O achieves a denser and more continuous oxide layer and a thicker transition layer. The weight loss of HTO-O scaffold was 20.13 % after 14 days of immersion in Hank's solution, which was much lower than that of HTO-A scaffold (53.70 %), indicating that undergoing HTO treatment in pure oxygen markedly enhances the scaffold's corrosion resistance.