**Jacek Górka 1,\*, Artur Czupry ´nski 1, Marcin Zuk ˙ 1, Marcin Adamiak <sup>2</sup> and Adam Kopy´s´c <sup>2</sup>**


Received: 6 June 2018; Accepted: 9 July 2018; Published: 10 July 2018

**Abstract:** Presented in this work are the properties and structure characteristics of MMA (Manual Metal Arc) deposited nanocrystalline coatings (Fe-Cr-Nb-B) applied to an iron nanoalloy matrix on an S355N steel substrate in relation to selected construction materials resistant to abrasive wear currently used in industry. The obtained overlay welds were subjected to macro and microscopic metallographic examinations; grain size was determined by X-ray diffraction (XRD), and chemical composition of precipitates was determined by energy-dispersive X-ray spectroscopy (EDS) during scanning electron microscopy (SEM). The size of the crystalline grains of the Fe-Cr-Nb-B nanocrystalline microstructure was analyzed using an Xpert PRO X-ray diffractometer. Analysis of the test results of the obtained layers of arc-welded Fe-Cr-Nb-B-type alloy confirmed that the obtained layers are made of crystallites with a size of 20 nm, which classifies these layers as nanocrystalline. The obtained nanocrystalline coatings were assessed by hardness and with the use of metal-mineral abrasion testing. The results of the coatings' properties tests were compared to HARDOX 400 alloy steel.

**Keywords:** abrasive wear; nanocrystalline layers; abrasion resistant plate; deposit weld
