Stainless Steels Case Study
AISI316L Stainless steels (SS) are widely used in biomedical industries to produce orthopedic implants, screws, cardiovascular stents and other surgery devices because of their proper mechanical properties and corrosion resistance at low cost [1–5]. However, they have represented some premature damages when utilized in the body environment. This sort of steels is susceptible to pitting corrosion and release of Ni, Mo and Cr ions in body environment which can intensify the risk of cancer and inflammatory reactions [6–10].
To alleviate the problem, a wide range of coating materials including Ta, TaCN, TaN, TiAlN, DLC, etc. [11–15], have been studied recently to improve the biocompatibility of AISI316 SS. Among them, the ceramic coatings are …show more content…
Then, they cleaned ultrasonically for 15 min in baths of acetone and ethanol sequentially before loading into the chamber. Figure 1 shows the schematic illustration of the planar D.C magnetron sputtering system which was applied to deposit tantalum film on AISI316L SS. The sputtering target was pure tantalum (99.95% purity) of diameter 20 mm. The distance from the target to the sample and the applied magnetic field were 7 cm and 20 mT, respectively. Also, the substrate temperature during deposition was kept constant at 200 ° C. Argon (99.999% purity) was entered into the chamber through mass flow controller. The base pressure of 5 ×10-6 torr in the chamber was reached. In order to eliminate residual contaminants and to increase film adhesion, sputter etch treatment was performed for 20 minutes on the substrate at an applied DC potential of 350 (V) and a process pressure of 100 mTorr. After that, the synthesis of tantalum films was started according to the design arrangement set, (Table 2). The deposition time for all samples was about 90 minutes.
Figure 1. Schematic diagram of the magnetron sputtering system
A TE-SCAN MIRA3 field emission scanning electron microscopy (FESEM) was applied to characterize films. An X-ray diffraction (XRD) was utilized using a Philips X’Pert MPD system to study the structure of the deposited film. The films adhesion was measured through a micro scratch test using a Rockwell C diamond indenter with the tip angle of 120˚ and 200 µm radius. Applied load linearly increased from 0.1 to 50
To alleviate the problem, a wide range of coating materials including Ta, TaCN, TaN, TiAlN, DLC, etc. [11–15], have been studied recently to improve the biocompatibility of AISI316 SS. Among them, the ceramic coatings are …show more content…
Then, they cleaned ultrasonically for 15 min in baths of acetone and ethanol sequentially before loading into the chamber. Figure 1 shows the schematic illustration of the planar D.C magnetron sputtering system which was applied to deposit tantalum film on AISI316L SS. The sputtering target was pure tantalum (99.95% purity) of diameter 20 mm. The distance from the target to the sample and the applied magnetic field were 7 cm and 20 mT, respectively. Also, the substrate temperature during deposition was kept constant at 200 ° C. Argon (99.999% purity) was entered into the chamber through mass flow controller. The base pressure of 5 ×10-6 torr in the chamber was reached. In order to eliminate residual contaminants and to increase film adhesion, sputter etch treatment was performed for 20 minutes on the substrate at an applied DC potential of 350 (V) and a process pressure of 100 mTorr. After that, the synthesis of tantalum films was started according to the design arrangement set, (Table 2). The deposition time for all samples was about 90 minutes.
Figure 1. Schematic diagram of the magnetron sputtering system
A TE-SCAN MIRA3 field emission scanning electron microscopy (FESEM) was applied to characterize films. An X-ray diffraction (XRD) was utilized using a Philips X’Pert MPD system to study the structure of the deposited film. The films adhesion was measured through a micro scratch test using a Rockwell C diamond indenter with the tip angle of 120˚ and 200 µm radius. Applied load linearly increased from 0.1 to 50