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Biocompatible metallic alloys (stainless steel, Ti-alloy, Co–Cr alloys, etc.) have been frequently used for various biomedical implants. Being biocompatible, complications like implant corrosion, body inflammation, organ pain, local infection, and cytotoxicity cannot be avoided. Hydroxyapatite, a common biomaterial, is used in the form of powders, coatings, and composites for biomedical applications. But poor adhesion, poor load-bearing capacity, high dissolution, poor wear resistance, natural fragility, etc. are the few hindrances in the use of hydroxyapatite coating over implants. Hence, there is a need to focus on the development of alternative biomaterials and their coatings for metallic (orthopedic, dental, metallic stents, pacemakers, etc.) implants. To avoid various complexities and to improve the biocompatibility of metal implants, the coating of forsterite and its composites are being used nowadays. Techniques like dip coating, plasma spraying, and electrophoretic deposition are employed for such coatings. In this paper, a review based on methods of preparation of forsterite has been done. For the preparation of forsterite powder, various studies have reported the sintering temperature range to be 800–1450 ℃ and the crystallite size from 10 nm to 100 µm. The forsterite and its composites coating over Ti-alloy and stainless steel have also been reported. This paper also compares the mechanical and biological properties of forsterite and hydroxyapatite. It has been observed that the mechanical properties (hardness, fracture toughness, Young’s modulus, and compressive strength), and biological properties (biocompatibility and bioactivity) of forsterite are favorable for the biomedical implant coating.

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The present work deals with the fabrication of forsterite–hydroxyapatite (FS–HA) hybrid coatings on stainless-steel 316L using the pulsed laser deposition (PLD) technique. The stainless steel (SS 316L) as a metallic implant is widely used in hard tissue applications. The XRD studies have confirmed the crystalline behavior of synthesized FS powder with an average crystallite size of 54[Formula: see text]nm. The synthesized FS powder was mixed in different compositions (10, 20, 30[Formula: see text]wt.%) into HA for preparing PLD targets (pellets). The XRD of the prepared pellets by UTM has confirmed both phases of FS and HA. The Scanning Electron Microscopy (SEM) of the coated samples depicted the successful deposition of composite powders on the substrates (SS 316[Formula: see text]L). The Ellipsometer was used to investigate the thickness of different substrates and it was found as 243, 251, 255, and 257[Formula: see text]nm for CP1, CP2, CP3, and CP4, respectively. The bioactivity of the coated substrates with different compositions (pure HA, 10%, 20%, 30%, and pure FS) was investigated by immersing the samples in simulated body fluid (SBF) for 14[Formula: see text]days. The same samples were then characterized by SEM which confirms the apatite layer formation that reflects the bioactivity. The addition of FS powder into HA will stimulate the apatite formation which enhances the bioactivity. The Raman Spectroscopy of coated samples reveals the successful deposition of different compositions of FS–HA nanocomposite. The peaks of Raman spectroscopy were corresponding to the XRD results of the pellets (different compositions of FS–HA). The antimicrobial activity of different compositions of FS–HA against Escherichia coli (E. coli) bacteria also showed a significant zone of inhibition. The bioactivity and antimicrobial behavior of FS–HA along with successful deposition by PLD have shown better potential applications for biomedical implant coating.