Investigation of tantalum oxynitride for hard and anti-corrosive coating application in diluted hydrochloric acid solutions. (June 2020)

• Record Type: Journal Article
• Authors: Hirpara, Jignesh; Chawla, Vipin; Chandra, Ramesh
• Is Part Of: Materials today communications. Volume 23(2020)
• Publication Date: 2020-06
• Subjects: Tantalum oxynitride -- Hydrochloric acid -- Nanoindentation -- Tafel plot -- Corrosion resistance; Materials science -- Periodicals; 620.11
• DOI: 10.1016/j.mtcomm.2020.101113
• Languages: English
• ISSNs: 2352-4928

Abstract

Highlights: Tantalum oxynitride coating was synthesized through optimization of reactive sputtering deposition parameters. Deposited coatings were having law roughness, good uniformity and without defects like pin holes or cracks. The coating was studied for mechanical behaviour and tantalum oxynitride has shown high hardness and mechanical strength. Coating reduces the corrosion current and offers high corrosion resistance compared to a native oxide film on steel. Low porosity and immune behaviour of tantalum enhances the anticorrosive behaviour of tantalum oxynitride for hard coatings. Abstract: Tantalum oxynitride coating was investigated for mechanical properties and corrosive behavior for the anti-corrosive applications. The material phases and surface morphology were investigated by XRD, XPS, FE-SEM and AFM. The hardness and corrosion tests were carried out using nanoindentation and potentiodynamic polarization technique in dilute HCl solutions at room temperature respectively. The results reveal that the coating is uniform and with low roughness (<10 nm). The tantalum oxynitride film has high mechanical strength in comparison to the other tantalum oxide coatings and 304-grade stainless steel substrate. In the presence of diluted HCl, it was observed that the severe attack of chloride ion destroyed the native passive film of the stainless steel and increases the corrosion rate (1.87 mmpy). The tantalum oxynitride coated specimen shows good resistance to such attack and reduce the corrosion current density significantly (60–80 %). The electrochemical impedance spectroscopy was performed to get an insight into coating behavior in the acidic media.