Wear Properties of Iron-Based Alloy Coatings Prepared by Plasma Transfer Arc Cladding

Abstract

Plasma transfer arc cladding technology has been widely utilized in surface engineering, repairing and remanufacturing. In the present work, multiple cladded thick claddings were prepared on compacted graphite cast iron (CGI) substrates with iron-based powders through plasma transfer arc cladding technology using different plasma arc currents to improve the surface wear resistance. The coatings’ phase and microstructure were analysed through XRD, SEM and EDS. The coatings’ microhardness and wear resistance were characterized. There were pearlite, graphite, austenite and secondary carbides in the iron-based alloy coatings. Due to the heat influence during the multiple cladding process, a spheroidal graphite transition zone appeared between the substrate and the coating. The microhardness of the claddings varied from 363 to 402 HV as the plasma arc current was changed from 45 to 60 A. With the increase of plasma arc current, the cladding’s microhardness increased. The iron-based coating’s minimum friction coefficient and wear mass loss were about 0.48 and 4.2 mg, respectively, when the plasma arc current was 60 A, which are lower values than those of the compacted graphite iron substrate with the friction coefficient and wear mass loss of 0.55 and 8.2 mg. Compared with the substrate, the iron-based alloy claddings achieved the effect of reducing friction and wear resistance simultaneously, which resulted from the self-lubricating effect of graphite and high wear-resistance of carbides in the claddings. The iron-based coatings had a similar abrasive wear mechanism to the CGI, which should be helpful to repair or remanufacture CGI workpieces.

Influence of Plasma Arc Current on the Friction and Wear Properties of CoCrFeNiMn High Entropy Alloy Coatings Prepared on CGI through Plasma Transfer Arc Cladding

“…In the bonding zone, there were comixed CoCrFeNiMn HEA solid solutions, ledeburite and fine acicular martensite formed near the compacted graphite iron for some parts remelted at very high heating and cooling speeds on the surface of the compacted graphite iron during plasma transfer arc cladding, which led to a great increase of the microhardness in the bonding zone. Meanwhile, in the heat affected zone, the pearlite in the compacted graphite iron substrate was heated and cooled quickly and changed to martensite with high hardness, which had been reported in references [35,40].…”

“…On the other hand, the contents of Co, Ni, Cr and Mn in the grains and grain boundaries were lower than those in the powder. The loss of powder elements during the rapid melting of HEA powders might be related to the lower saturation vapor pressure [40]. At the grain boundaries of the coating, there were 2.51 wt.% oxygen, which was higher than that in powders without significant oxygen.…”

Effect of Heat Treatment on the Microstructure and Mechanical Properties of Plasma Cladded CoCrFeNiMn Coatings on Compacted Graphite Iron

“…Currently, the surface modification and repair technology represent the most popular preparation process for high-entropy alloy coatings. It can be categorized into laser cladding technology [12,13], plasma cladding [14,15], thermal spraying [16], cold spraying [17], electron-beam sputtering technology [18], electrochemical deposition technology [19], etc. As compared to the commonly used methods, plasma cladding technology has the subsequent advantage characteristics including high powder deposition rate, low dilution rate, high cladding efficiency, wide selection of cladding materials and sensible method controllability so that it was preferred to prepare HEA coatings.…”

The Effect of Heat Treatment on the Microstructure and Mechanical Properties of Plasma-Cladded CoCrFeNiMn Coatings on Compacted Graphite Iron

“…Currently, surface modification and repair technology represent the most popular preparation process for high-entropy alloy coatings. It can be categorized into laser cladding technology [13,14], plasma cladding [15,16], thermal spraying [17], cold spraying [18], electron-beam sputtering technology [19], electrochemical deposition technology [20], etc. Compared to the commonly used methods, plasma cladding technology has the following advantage characteristics, including a high powder deposition rate, low dilution rate, high cladding efficiency, a wide selection of cladding materials, and sensible method controllability so it was preferred to prepare HEA coatings.…”