The rapid degradation rate has been a hindrance to promote the clinical application of biodegradable magnesium (Mg). To solve this problem, researchers have devoted to the surface modification of Mg for years. Magnesium fluoride (MgF₂) coating is easy to obtain and has excellent corrosion resistance, which has long-term research value in surface modification of magnesium implants. However, we are still lacking in understanding the influence of process parameters, sizes of film and other factors on the protective effect of MgF₂ coating, and its biocompatibility also needs to be verified. In this paper, the sizes, corrosion resistance and biocompatibility of the chemical conversion film (MgF₂) with different preparation time were studied. Through in vitro immersion, electrochemical simulation, structure and composition analysis and cytotoxicity test, we derived the rules that the MgF₂ film with greater thickness and better corrosion resistance was prepared under longer preparation time. The differences of several characterization methods were compared. Meanwhile, we demonstrated that the MgF₂ film had great cytocompatibility and the attachment and growth of osteoblasts on the surface of the film were quite satisfied. These conclusions are of great significance for the applications of the MgF₂ film in orthopedic clinical implantation.

快速的降解速度一直是促进可生物降解镁（Mg）的临床应用的障碍。为了解决这个问题，研究人员多年来一直致力于镁的表面改性。氟化镁（MgF ₂）涂层易获得且具有优异的耐腐蚀性能，在镁植入物的表面改性方面具有长期的研究价值。然而，我们对工艺参数、薄膜尺寸等因素对MgF ₂涂层保护效果的影响仍缺乏了解，其生物相容性也有待验证。本文对化学转化膜（MgF ₂) 对不同的准备时间进行了研究。通过体外浸泡、电化学模拟、结构和成分分析以及细胞毒性试验，我们得出了在更长的制备时间下制备出厚度更大、耐腐蚀性更好的MgF ₂薄膜的规律。比较了几种表征方法的差异。同时，我们证明了MgF ₂膜具有很好的细胞相容性，并且成骨细胞在膜表面的附着和生长非常令人满意。这些结论对MgF ₂薄膜在骨科临床植入中的应用具有重要意义。