Effect of deposition current on microstructure and properties of CoCrWC alloy PTA coatings

Abstract

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Effect of Dilution on the Microstructure and Properties of CoCrMoSi alloy Coatings Processed on High-Carbon Substrate

“…Thus, to promote distinct dilution, coatings were prepared by PTA-P as single beads with four distinct deposition currents: 120, 150, 180 and 200 A. The procedure is in agreement with previous experience and results presented in the literature for such an approach 11,13,24,[26][27][28] . Table 2 shows the main deposition parameters utilized.…”

“…6 and 7). Opposed to what has been previously observed regarding the effect of dilution with iron-base alloy substrates on the T400 alloy, in which a decrease in hardness was found [24][25][26] , the processing on highcarbon cast iron was able to maintain or even increase the high coatings hardness. From the nanoindentation tests, it can be noticed that labyrinth-like eutectics (120 and 150 A) presented a slight hardness increase from 7.1 and 7.7 GPa, respectively.…”

Effect of Track Overlap on the Microstructure and Properties of the CoCrMoSi PTA Coatings

“…The production of welded coatings must consider the interaction between the deposition alloy and the substrate, as higher dilution induces lower hardness of the coatings. This reduction in hardness has been attributed to several factors, including the participation of the chemical elements (such as iron, chromium and nickel) from the steel substrates [10][11][12] . Coatings are largely studied by way of dilution on single track deposits processed with different deposition current 10,11 .…”

Effect of Bead Overlapping on the Microstructure and Mechanical Properties of CoCrWC Alloy Coatings

“…Among the options, the carbide reinforced alloy system can be selected for its inherent high strength, wear and corrosion resistance and ability to retain hardness at elevated temperatures 7 . Its microstructure consists of hard carbide particles dispersed in a cobalt-rich solid solution matrix (Co-SS) 7,8 .Therefore, chemical composition considerably influences microstructure and, of course, mechanical properties and resistance to abrasion, since it dictates the volume fraction of carbides [1][2][3]7,8 .…”

“…Moreover, the hardfacing of steel substrates has been considered for their attractive properties and relatively low cost. In fact, dilution should be kept as low as possible, since higher dilution induces a decrease in hardness often associated with microstructure changes, that is, a lower fraction of strengthening carbides and lower alloying in the Co-SS 8,[11][12][13][14][15] . Halstead and Rawlings 16 have investigated the effect of iron additions on Co-based alloys microstructure, and many recent welding papers 8,12,14,15 have confirmed a larger fraction of Co-rich solid solution phase as higher dilution in the steel substrate is achieved 8 .…”