Microstructure, Microhardness, Corrosion Resistance and Chemical Composition of Mo, B and Mo-B Coatings Produced Using Laser Processing

• Main Authors: Aneta Bartkowska, Dariusz Bartkowski, Mikołaj Popławski, Adam Piasecki, Damian Przestacki, Andrzej Miklaszewski
• Format: Article
• Language: English
• Published: MDPI AG 2020-07-01
• Series: Materials
• Subjects: molybdenum; boron; laser alloying; microhardness; corrosion resistance; XRD
• Online Access: https://www.mdpi.com/1996-1944/13/15/3249

The paper presents study results of laser alloying of CT90 tool steel with an applied pre-coat of boron, molybdenum or a mixture of these elements. Pre-coats were applied on steel substrates in the form of a paste. The aim of the study was to investigate the microstructure, chemical and phase composition, microhardness and corrosion resistance of these newly-formed coatings. The laser alloying process was carried out using a diode laser with a nominal power of 3 kW. In this study a laser beam power of 900 W and a scanning speed of 48 mm/s were used. As a result of the laser beam action, the presence of three areas was observed in cross-sections of specimens: a remelted zone, a heat affected zone and the substrate. The properties of coatings enriched with both molybdenum and boron were better than those of the steel substrate, but only the use of a Mo-B mixture resulted in a significant improvement in microhardness and corrosion resistance.