Formation of abrasion-resistant coatings of the AlSiFe_xMn_y intermetallic compound type on the AISI 304L alloy

Abstract

ABSTRACT:The α-Al 9 FeMnSi and β-Al 9 FeMn 2 Si intermetallics formed by reactive sintering of Al, Si, Mn, Fe, Cr and Ni powders have been used in AISI 304L steels to enhance microhardness. Processing variables of the reactive sintering treatment were temperature (600, 650, 700, 750 and 800 °C), pressure (5, 10 y 20 MPa) and holding time (3600, 5400 y 7200 seconds). Experimental results show that temperature is the most important variable affecting the substrate/coating formation, while pressure does not appear to have a significant effect. The results show the optimum conditions of the reactive sintering that favor the substrate/coating formation are 800 °C, 20 MPa and 7200 seconds. Under these conditions, the reaction zone between the substrate and coating is more compacted and well-adhered, with a microhardness of 1300 Vickers. The results of SEM and X-Ray diffraction confirmed the formation of α-Al 9 FeMnSi and β-Al 9 FeMn 2 Si intermetallics in the substrate/coating interface as well as the presence of Cr and Ni, indicating diffusion of these two elements from the substrate to the interface. RESUMEN: Formación de recubrimientos resistentes a la abrasión de compuestos intermetálicos del tipo AlSiFe x Mn y sobre la aleación AISI 304L.Los intermetálicos α-Al 9 FeMnSi y β-Al 9 FeMn 2 Si formados por sinterización reactiva de polvos Al, Si, Mn, Fe, Cr, Ni se han utilizado en aceros AISI 304L para mejorar la microdureza. Las variables de procesamiento de sinterización reactiva fueron temperatura (600, 650, 700, 750, y 800 °C), presión (5, 10 y 20 MPa) y el tiempo de retención (3600, 5400 7200 segundos). Los resultados experimentales muestran que la temperatura es la variable más importante que afecta a la formación del sustrato/recubrimiento, mientras que la presión no parece tener un efecto significativo una influencia significativa. Los resultados muestran las condiciones óptimas de la sinterización reactiva que favorecen la formación del sustrato/recubrimiento a 800 °C, 20 MPa y 7200 segundos. En estas condiciones, la zona de reacción entre el sustrato y el recubrimiento es más compacta y bien adherida, con microdureza de 1300 Vickers. Los resultados de MEB y DRX confirman la formación de intermetálicos α-Al 9 FeMnSi y β-Al 9 FeMn 2 Si en la interfase sustrato/ recubrimiento, así como la presencia de Cr y Ni, indicando la difusión de estos dos elementos del sustrato a la interfaz.

Wearing Behavior of the α-Al9FeMnSi Intermetallic Compound Formed by Reactive Sintering onto AISI 304L Stainless Steel

“…The Al, Si, MnSi, and α-Al 9 FeMnSi phases were detected on the interface. The coating XRD pattern shows dominant peaks of the α-Al 9 FeMnSi and β-Al 9 FeMn 2 Si phases, which is consistent with results reported in literature [25,26]. The work carried out by Toscano presents a broad discussion of the origin of the indexation of the quaternary intermetallic phases of the AlSiFeMn type that precipitate the composition range studied in this work, which has allowed assigning the α-Al 9 FeMnSi stoichiometry as the dominant phase in this system in the composition range set.…”

“…Finally, as can be observed, the intermetallic coating is uniform, with high adherence to the substrate. The coating is mainly composed of 48.96 wt.% Al, 12.66 wt.% Si, 18.21 wt.% Mn, and 20.17 wt.% Fe, closely corresponding to the chemical structure of the α-Al9FeMnSi intermetallic phase, according to the measurements of Toscano [25] and Martínez [26]. In the substrate XRD pattern, the peaks at 44 • , 51 • , and 75 • are associated to the γ-Fe (austenite) phase of AISI 304L stainless steel [5].…”

“…In each experiment, a disk of powders was placed on a stainless steel disk and then this setup was sintered during 7200 s at 800, 850, or 900 • C and under applied pressure of 15 or 20 MPa. These operating parameters were selected from previous works [25,26]. In an infrared radiation device fitted with a quartz tube positioned coaxially with the loading axis of a universal Instron testing machine (Instron Mechanical Testing, Norwood, MA, USA), pressure and heat were simultaneously applied to the samples.…”

“…These authors found that at temperatures above 700 • C, reactive sintering of powders occurred. Martínez-Perales et al [26] reported the effect of processing parameters related to the creation of coatings of AlSiFe x Mn y intermetallics by reactive sintering. Previous work carried out by authors on the formation of the Al 9 FeMnSi intermetallic compound included the use of the differential thermal analysis technique by placing thermocouples inside the pre-compacted tablets of the elemental powders Al, Si, Fe, and Mn [26].…”

“…Martínez-Perales et al [26] reported the effect of processing parameters related to the creation of coatings of AlSiFe x Mn y intermetallics by reactive sintering. Previous work carried out by authors on the formation of the Al 9 FeMnSi intermetallic compound included the use of the differential thermal analysis technique by placing thermocouples inside the pre-compacted tablets of the elemental powders Al, Si, Fe, and Mn [26]. In the mentioned work, it was shown that approximately at 580 • C, an endothermic event occurs associated with the formation of a liquid solution Al Si, and subsequently, as the temperature increases, exothermic events occur between 600 and 800 • C related to the formation of intermediate phases such as Al, Fe, Si o Al, Si, and Mn and even the quaternary Al 9 FeMnSi.…”