Tribological behaviour of TiB2 ceramic based composite coating deposited on stainless steel AISI 304 by gas tungsten arc (GTA) cladding process

Abstract

Abstract In this study, Titanium (Ti)-Titanium diboride (TiB2) metal matrix composite (MMC) cladding layers were fabricated on an AISI 304 stainless steel substrate by the gas tungsten arc (GTA) cladding process. The composite cladding layer was produced using different powder mixtures: 85 wt% TiB2−15 wt% Ti, 75 wt% TiB2−25 wt% Ti, and 65 wt% TiB2 −35 wt% Ti. During cladding, the GTA process currents were used in the range of 70 A to 90 A with 10 A interval differences and the scan speed in the range of 1.1 mm sec−1 to 1.9 mm s−1 with 0.4 mm s−1 interval differences. All samples were investigated for mechanical properties, microstructure, and phase analysis by Vickers microhardness, scanning electron microscopy (SEM), Energy dispersive x-ray spectroscopy (EDX), and x-ray diffraction (XRD) respectively. The x-ray diffraction (XRD) findings indicate that the composite coatings consist of TiB2, TiB, Ti, Fe3C, B4C, and NiTi phases. The presence of elements B, C, Ti, Cr, Mn, Fe, and Ni in the coating was confirmed by x-ray energy dispersive spectroscopy (EDX). The maximum microhardness value of the composite coating was enhanced in the range of 1639 HV0.1 to 3781 HV0.1, whereas the microhardness of the AISI 304 stainless steel substrate was 194 HV0.1. The average wear rate of the coated samples was determined in the range of 11.09 × 10−9 g N−1-m−1 to 27.63 × 10−9 g N−1m−1, whereas the average wear rate of the AISI 304 steel substrate was 88.414 × 10−9 g N−1m−1. It can be concluded that the maximum micro-hardness of the composite coating increased by 9-19 times than that of the nominal substrate (AISI 304 stainless steel). Also, the wear resistance of the composite coating enhanced by 8 times as compared to AISI 304 steel substrate. It is demonstrated in this study that the processing current, TiB2 content, and scanning speed have significant effect on the microstructure, mechanical, and tribological features of the cladding layers under consideration.