TABLE 1.

Main results of physical methods application on titanium and its alloys.

Methods	Coating quality	Process rate	Bond strength	Osteogenesis and antibacterial function	Applications
Plasma spray technology (Hanawa, 2019; Ke et al., 2019)	Dense coating, high bonding strength, difficult to oxidize spray material	Not available	20–80 MPa	Enhanced osseointegration, osteoblast proliferation and rapid bone repair.	Wide range of materials, suitable for a variety of coatings
Plasma immersion ion implantation (Yu et al., 2017; Shanaghi and Chu, 2019b)	Inert to surface thin injection layer, good biocompatibility.	Not available	Not available	Inhibition of Staphylococcus aureus and Escherichia coli (E. coli)	Used for large, heavy. and complex shaped workpieces
Plasma immersion ion implantation and deposition (Yang et al., 2007; Yu et al., 2017)	Easy composition control, improved density and adhesion, suitable for three-dimensional and complex surfaces	≈30–40 nm min–1 in thickness	Very high	Rapid osseointegration and continuous biomechanical stability, reduction of gram-negative E. coli and Pseudomonas aeruginosa	Used for precision parts with high added value to improve the wear resistance
Physical vapor deposition (Behera et al., 2020; Liu et al., 2020)	Uniform and dense film, strong bonding force	≈25–1,000 nm min–1 in thickness	Moderate	Surface modification to increase the contact area, good blood compatibility	Suitable for preparation of special functional composite membrane