Influences of Surface Finishes on Properties of Biological Zinc Phosphate Conversion Coating on Titanium

Abstract

Chemically formed phosphate conversion coatings (PCC) usually have good adhesion strength due to in situ growth and have great potential for biomedical applications. However, the fabrication of PCC on titanium (Ti) metals has seldom been studied because inherent chemical inertia and oxide layer block the dissolving process. Previously, the authors successfully fabricate intact PCC on pure Ti by a novel hydrothermal phosphorization method, and the coating shows good adhesion. However, metallographically polished specimens are used only in order to eliminate the influences of surface topography. In this study, the feasibility of such method to be performed on sandpaper polished and acid‐etched pure Ti are studied. Results show that rough surface benefit the nucleation of PCC and refine the crystal size, whereas, a smooth surface allow sufficient growth of crystal grain resulting in a thicker coating with stronger adhesive strength. In spite of rough surface, PCC formation on acid‐etched Ti is depressed due to the existence of titanium hydride. All the coatings obviously improve corrosion resistance of Ti substrate. The cytotoxicity test suggests that the PCCs present no adverse effects on L‐929 cells and has a cytotoxicity ranking of 0–I grade. The study shows that the hydrothermal zinc phosphorization has a potential to be extensively used for Ti‐based implants with different surface finishes.

Microstructural characterization and film-forming mechanism of a phosphate chemical conversion ceramic coating prepared on the surface of 2A12 aluminum alloy

“…As shown in Fig. 9A, the critical load of PCC ceramic coatings was 178.55 N. Compared with critical load of other coatings, [50][51][52] the PCC ceramic coating own the excellent adhesion strength (Table S2 †), which could be explained as follows: in the rst place, the AlPO 4 , AlF 3 and AlOOH in PCC ceramic coating were bonding with Al substrate through strong chemical bond and physical means. In the second place, the alkaline etching in pretreatment process created a rougher surface was benet for situ growth of PCC coating, which boosting the bond strength between coating and Al substrate.…”

Enhanced film quality of PbS QD solid by eliminating the oxide traps through an in situ surface etching and passivation

“…Semiconductor quantum dots (QDs) have attracted considerable interest due to their tunable optical and electronic properties that enable their potential applications in optoelectronic devices. 1–5 Of particular interest is PbS, which has been extensively studied for various applications, such as near-infrared (NIR) photodetectors and solar cells, 6–10 because of its brilliant optical and electrical properties of a narrow bandgap, a large Bohr radius, and a high absorption coefficient as well as potential multiple exciton generation. Although great progress has been achieved through surface and energy band engineering as well as device architecture optimization, further improvements in device performance are required to make them competitive.…”