Obtaining of micro-powder coatings from Fe-Ni and Fe-Cr alloys by pulse-periodic laser action

Abstract

This paper presents the results of experimental research concerning the laser-plasma coating of steel substrate with the following powder grades: AP-FeCr4MnSiB (Fe71.75C4.81Cr3.33Si3.54B14.10Mn1.74V0.73), AP-FeCr11Mn4SiB (Fe66.8Mn2.84C2.85Si5.3B11.42Cr10.79), AP-FeNi19Mn10SiB (Fe56.12Ni15.82C1.65Si4.92B12.82Mn8.66) and AP-G14 (Fe29.4Ni32.24C5.32Cr14.78Si4.06B10.22Mo2.8W1.16). As a focusing head was used self-made lateral nozzle for feeding powder. The nozzle was used in conjunction with scanning the laser radiation in the direction perpendicular to the movement of the focusing head. Coated tracks with various nozzle head movement speed (7-20 mm/s) was obtained. The elemental compositions of the resulting coatings were studied. Alloying elements are uniform distributed throughout the coating. During surfacing the powder particles are completely melted and partially mixed with the base material. This leads to increased iron content in the resulting coatings compared with the original powder. The hardness and thickness of the deposited layers were measured depending on the speed of the process. The hardness of the coatings is in the range of 7-12 GPa, the thickness is 0.15-0.7 mm. The wear resistance of the resulting coatings is up to 10 times higher than that of a steel substrate.