A time-based potential step analysis of electrochemical impedance incorporating a constant phase element: A study of commercially pure titanium in phosphate buffered saline

The electrochemical behavior of commercially pure titanium (CP Ti) and Ti-6Al-4V (Grade 5) alloy in phosphate buffered saline solution (PBS, pH = 7.4) at 37 °C (i.e., in simulated physiological solution in the human body) was examined using open circuit potential measurements, linear and potentiodynamic polarization and electrochemical impedance spectroscopy methods. After the impedance measurements and after potentiodynamic polarizationmeasurements, the surface of the samples was investigated by scanning electron microscopy, while the elemental composition of oxide film on the surface of each sample was determined by EDS analysis. The electrochemical and corrosion behavior of CP Ti and Ti-6Al-4V alloys is due to forming a two-layer model of surface oxide film, consisting of a thin barrier-type inner layer and a porous outer layer. The inner barrier layer mainly prevents corrosion of CP Ti and Ti-6Al-4V alloy, whose thickness and resistance increase sharply in the first few days of exposure to PBS solution. With longer exposure times to the PBS solution, the structure of the barrier layer subsequently settles, and its resistance increases further. Compared to Ti-6Al-4V alloy, CP Ti shows greater corrosion stability.

Download Full-text

Bioactive Coatings Formed on Titanium by Plasma Electrolytic Oxidation: Composition and Properties

Materials ◽

10.3390/ma13184121 ◽

2020 ◽

Vol 13 (18) ◽

pp. 4121 ◽

Cited By ~ 3

Author(s):

Dmitry V. Mashtalyar ◽

Konstantine V. Nadaraia ◽

Andrey S. Gnedenkov ◽

Igor M. Imshinetskiy ◽

Mariia A. Piatkova ◽

...

Keyword(s):

Plasma Electrolytic Oxidation ◽

Electrochemical Impedance ◽

Pure Titanium ◽

Corrosion Current ◽

Bare Metal ◽

Commercially Pure Titanium ◽

Bioactive Coatings ◽

Commercially Pure ◽

Electrolytic Oxidation ◽

Plasma Electrolytic

Bioactive coatings on VT1-0 commercially pure titanium were formed by the plasma electrolytic oxidation (PEO). A study of the morphological features of coatings was carried out using scanning electron microscopy. A composition of formed coatings was investigated using energy-dispersive spectroscopy and X-ray diffractometry analysis. It was shown that PEO-coatings have calcium phosphate in their composition, which increases the bioactivity of the surface layer. Electrochemical properties of the samples were studied by potentiondynamic polarization and electrochemical impedance spectroscopy in different physiological media: simulated body fluid and minimum essential medium. The data of electrochemical studies indicate more than 15 times decrease in the corrosion current density for the sample with coating (5.0 × 10−9 A/cm2) as compared to the bare titanium (7.7 × 10−8 A/cm2). The formed PEO-layers have elastoplastic properties close to human bone (12–30 GPa) and a lower friction coefficient in comparison with bare metal. The wettability of PEO-layers increased. The contact angle for formed coatings reduced by more than 60° in comparison with bare metal (from 73° for titanium to 8° for PEO-coating). Such an increase in surface hydrophilicity contributes to the greater biocompatibility of the formed coating in comparison with commercially pure titanium. PEO can be prospective as a method for improving titanium surface bioactivity.

Download Full-text

RMI 0.2% Pd

Alloy Digest ◽

10.31399/asm.ad.ti0074 ◽

1979 ◽

Vol 28 (12) ◽

Keyword(s):

Corrosion Resistance ◽

Crevice Corrosion ◽

Elevated Temperatures ◽

Pure Titanium ◽

Heat Treating ◽

Low Ph ◽

Commercially Pure Titanium ◽

Bend Strength ◽

Commercially Pure ◽

Minimum Yield

Abstract RMI 0.2% Pd is a grade of commercially pure titanium to which up to 0.2% palladium has been added. It has a guaranteed minimum yield strength of 40,000 psi with good ductility and formability. It is recommended for corrosion resistance in the chemical industry and other places where the environment is mildly reducing or varies between oxidizing and reducing. The alloy has improved resistance to crevice corrosion at low pH and elevated temperatures. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and bend strength. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ti-74. Producer or source: RMI Company.

Download Full-text

UPM CP TITANIUM GRADE 3 (UNS R50550)

Alloy Digest ◽

10.31399/asm.ad.ti0167 ◽

2020 ◽

Vol 69 (6) ◽

Keyword(s):

Corrosion Resistance ◽

Pure Titanium ◽

Heat Treating ◽

Commercially Pure Titanium ◽

Commercially Pure ◽

Continuous Service ◽

Pure Grade ◽

Grade 3 ◽

Titanium Grade ◽

Design Stress

Abstract UPM CP Titanium Grade 3 (UNS R50550) is an unalloyed commercially pure titanium that exhibits moderate strength (higher strength than that of Titanium Grade 2), along with excellent formability and corrosion resistance. It offers the highest ASME allowable design stress of any commercially pure grade of titanium, and can be used in continuous service up to 425 °C (800 °F) and in intermittent service up to 540 °C (1000 °F). This datasheet provides information on composition, physical properties, and elasticity. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ti-167. Producer or source: United Performance Metals.

Download Full-text