Study of the Role of Titanium and Iron Cathodic Cages on Plasma-Nitrided AISI 430 Ferritic Stainless Steel

Mirza Z Babur; Aiyah S Noori; Zafar Iqbal; Muhammad Shafiq; Muhammad Asghar; Abdulaziz H Alghtani; Vineet Tirth; Ali Algahtani; Abid Zaman

doi:10.3390/mi13101739

Study of the Role of Titanium and Iron Cathodic Cages on Plasma-Nitrided AISI 430 Ferritic Stainless Steel

Micromachines (Basel). 2022 Oct 14;13(10):1739. doi: 10.3390/mi13101739.

Authors

Mirza Z Babur¹, Aiyah S Noori², Zafar Iqbal¹, Muhammad Shafiq³, Muhammad Asghar³, Abdulaziz H Alghtani⁴, Vineet Tirth^{5

6}, Ali Algahtani^{5

6}, Abid Zaman¹

Affiliations

¹ Department of Physics, Riphah International University, Islamabad 44000, Pakistan.
² Medical Physics Department, Al-Mustaqbal University College, Hillah 51001, Iraq.
³ Department of Physics, Quaid-i-Azam University, Islamabad 45320, Pakistan.
⁴ Department of Mechanical Engineering, College of Engineering, Taif University, Taif 21944, Saudi Arabia.
⁵ Mechanical Engineering Department, College of Engineering, King Khalid University, Abha 61421, Saudi Arabia.
⁶ Research Center for Advanced Materials Science (RCAMS), King Khalid University Guraiger, Abha 61413, Saudi Arabia.

Abstract

In contrast to austenitic and martensitic stainless steels, ferritic stainless steels have a lower hardness and wear resistance but exhibit excellent corrosion resistance. Due to this fact, their use in the aerospace, automobile, and house construction industries is restricted. Several methods have been utilized to enhance the tribological characteristics of ferritic stainless steels. In this work, titanium nitride coating has been carried out by using a cathodic cage of titanium material, and later on, the titanium cathodic cage is replaced by an AISI-304 cathodic cage in a CCPN chamber to form iron nitride coating on AISI-430 ferritic stainless steel coupons through a plasma nitriding process for 4 h at a fixed temperature of 400 °C. The microstructures and mechanical traits of all processed and control coupons were analyzed using scanning electron microscopy, X-ray diffraction, ball-on-disc wear tester, and microhardness tester techniques. The results showed that hardness increased up to 1489 HV with the titanium cage, which is much higher than the hardness of the base material (270 HV). The titanium cage-treated coupons have high layer thickness, smooth surface morphology, and a minimum crystallite size of 2.2 nm. The wear rate was reduced up to 50% over the base material after the titanium cage plasma treatment. The base coupon exhibited severe abrasive wear, whereas nitrided coupons exhibited dominant adhesive wear. In the iron nitride coatings, this effect is also important, owing to the more influential cleaning process in a glow discharge, and the better adhesion with enhanced interlayer thickness is attributed to the fact that the compliance of the interlayer minimizes shear stresses at the coating-substrate interface. The use of a graded interface improves adhesion compared with the case where no interlayer is used but a titanium interlayer of comparable thickness provides a significant increase in measured adhesion. For both titanium and iron nitride films, there is a reduction in wear volume which is a function of interlayer thickness; this will have a substantial effect on wear lifetime. Thus by careful control of the interlayer thickness and composition, it should be possible to improve coating performance in tribological applications.

Keywords: ferritic stainless steel; plasma nitriding; surface hardness; titanium cathodic cage.

Grants and funding

Taif University Researchers Supporting Project number (TURSP-2020/349), Taif University, Taif, Kingdom of Saudi Arabia and the Deanship of Scientific Research at King Khalid University Abha 61421, Asir, Kingdom of Saudi Arabia Large Groups Project under grant number RGP.2/225/43.