Tribology International 143 (2020) 106002 Available online 16 October 2019 0301-679X/© 2019 Elsevier Ltd. All rights reserved. Abrasion resistance of Ni-Cr-B-Si coating deposited by laser cladding process ☆ Jurandir Marcos S� a de Sousa a, * , Francisco Ratusznei a , Milton Pereira a , Richard de Medeiros Castro b , Elvys Isaías Mercado Curi b a Laborat� orio de Mec^ anica de Precis~ ao, Universidade Federal de Santa Catarina, Florian� opolis, Brazil b Laborat� orio de Vibraç~ oes e Tribologia, Faculdade SATC, Criciúma, Brazil A R T I C L E INFO Keywords: Abrasion resistance Chromium carbides Thermal gradient Cooling cracks ABSTRACT Ni-Cr-B-Si alloy deposited by laser cladding has its tribological performance evaluated. Deposition parameters selection is a diffcult task. In this work, Ni-Cr-B-Si coatings were deposited by a fber laser source with a coaxial powder nozzle on low carbon steel substrate. Microstructure, microhardness and abrasive wear tests were per- formed. Results showed coatings with good surface adhesion. Microhardness was 10% higher in coatings with higher concentration and phase size of chromium carbides. Volumetric loss and wear coeffcient showed 10% variation between the coatings. Coatings with different thermal gradients showed different dilution levels, affecting their abrasion resistance. The better tribological performance was obtained for coatings with lower cooling cracks density and higher volumetric fraction of carbides, which both mitigated wear micromechanism action. 1. Introduction Currently, surface engineering has proposed new technologies and alloys to enhance the performance of mechanical components. The materials subjected to severe wear require coatings that increase the lifetime of machine elements, and consequently, minimize fnancial losses due to shutdowns for the maintenance and replacement of worn components. Among the various types, abrasive wear mechanisms are the most frequently encountered, resulting from the friction and sliding between the hard particles and the surface of solid components. Industry accounts for approximately 30% of total world energy consumption [1]. About 23% of these 30% come from tribological contacts [2]. Sectors of great economic importance, such as the agri- cultural, oil and gas and mining industry, requires and are interested in increasing their components lifetime. In mining, for example, 40% of the expenses related to friction losses, 27% of the deteriorated parts replacement, 26% of the workforce and 7% of production losses can be avoided using effcient tribological solutions [3]. The environment can also be greatly benefted by advanced and effcient tribological solutions implementation. An extensive study has shown that in the short term (approximately 8 years), on a global scale, due to the implementation of advanced tribological technologies, CO 2 emission reduction can be as much as 1.460 Mt, representing a saving of 455.000 € (Euros). In the long term (around 15 years), these values rise to 3.140 Mt and 970.000 €, respectively [2]. According to this context, it is important to improve the tribological properties, especially abrasive wear resistance, which causes volume loss, dimensional changes and failures in mechanical and related com- ponents. Thus, the search for alternative manufacturing processes that provide cost-effective features has become a constant aim for research centers around the world. One adopted solution is the application of hard coatings by deposi- tion processes, such as thermal spraying and arc welding processes. In these techniques, layers with special properties are deposited over a lower mechanical strength substrate. Instead of manufacturing parts composed entirely by special materials, only the surface area of interest is coated, and this approach can drastically reduce the components fnal cost. Despite the cited processes can generate acceptable results, there are still challenges to be overcome to allow high quality coatings production without problems related to distortions appearance, lack of metallur- gical adhesion between substrate and addition material, extensive heat ☆ This Work was presented at TRIBOBR2018. * Corresponding author. E-mail address: jurandirmarcos37@gmail.com (J.M.S. Sousa). Contents lists available at ScienceDirect Tribology International journal homepage: http://www.elsevier.com/locate/triboint https://doi.org/10.1016/j.triboint.2019.106002 Received 4 August 2019; Received in revised form 1 October 2019; Accepted 3 October 2019