Fabrication and Characterization of Ni60A Alloy Coating on Copper Pipe by Plasma Cladding with Induction Heating

The Influence of Laser Remelting Parameters on the Surface Quality of Copper

In order to improve the surface quality of copper after laser remelting, this article took laser frequency, pulse width, and energy density as the research objects and used scanning electron microscopy (SEM), a laser confocal three-dimensional measurement instrument, hardness tester, and friction and wear measurement instrument to study the surface morphology, surface roughness, microhardness, and wear resistance of copper, respectively. The results indicate that the frequency, pulse width, and energy density of laser remelting could directly affect the surface quality of the sample, but the influence of frequency and pulse width was more significant. When the laser remelting frequency was 10 Hz, the pulse width was 10 ms, and the energy density was 132.69 J/mm2, the sample exhibited good surface morphology, roughness, and wear resistance. The relevant research in this article can provide a good reference for the laser surface treatment of copper-based materials.

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

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.