Issue 78

N. Mohan et alii, Frattura ed Integrità Strutturale, 78 (2026) 129-145; DOI: 10.3221/IGF-ESIS.78.08

Figure 1: Schematic representation of test set up used for corrosion, wear and tribocorrosion measurements.

Dry sliding wear test The dry sliding wear test was carried out on a ball-on-disk tribometer (TR- 201E-M2, DUCOM, Bangalore, India) using alumina ball of 10 mm diameter (Jayashree Spheres and Measures, India), at 10 N load and sliding velocity of 0.1 m/s without the addition of electrochemical solution. Tribocorrosion test The tribocorrosion tests were performed in a ball-on-disk tribometer connected to a Gamry1000® potentiostat (Fig. 1). Both potentiodynamic polarization and wear tests were conducted simultaneously. The test conditions used in tribocorrosion are same as was used in the individual corrosion and dry sliding wear tests mentioned above. The wear test commenced after the initial delay of 900 s. Using continuous data recording software (WINDUCOM-2000TM) interfaced with the tribometer, real-time frictional force data was recorded to calculate the coefficient of friction (COF) during dry sliding wear and tribocorrosion testing. The test specimens as well as alumina counterface were ultrasonically washed in acetone for 15 minutes to eliminate debris from the worn surfaces before examination. A non-contact optical profilometer (Sigma, Rtec Instruments, USA) was used to measure the wear tracks' surface profiles, which were then examined using Gwyddion 2.6 software to produce comprehensive wear track and scar profiles. The average cross sectional area of the wear scar obtained from at least six profile traces recorded at various locations as well as the wear track perimeter were used to calculate the wear rate of the composites. The following formula was used to calculate the wear rate (mm³/Nm) in both tribocorrosion and dry sliding conditions:

AP FL



W

(1)

where; A: area under the wear scar profile, P: perimeter of the wear track, F: normal load (N), and L: total sliding distance (m). Further, the wear rate of the counter body Wb (in mm 3 /Nm) was measured using the equation below:

3 a b DFL 



(2)

W

b

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where; a: major diameter of the wear scar, b: minor diameter of the wear scar, D: diameter of alumina counter body. The measurements related to counter body wear scars were obtained from SEM micrographs. All the tests were repeated minimum of five times to ensure repeatability.

R ESULTS AND DISCUSSION

Microstructural characteristics of boronized layer ig. 2 shows the optical micrograph of the 16Cr5Ni SMSS boronized at 950°C. The striking features that can be seen in the micrograph are the three distinct zones. The outermost is the boronized layer followed by the intermediary zone of diffusion and then the substrate. On the boronized layer the Fe 2 B and FeB compounds can be identified. In order to obtain the boronized layer of requisite thickness and composition the optimization of boronizing F

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