Azarmi Fardad, Tangpong Xiangqing W
Department of Mechanical Engineering, North Dakota State University, Fargo, ND 58108, USA.
Materials (Basel). 2023 Sep 27;16(19):6422. doi: 10.3390/ma16196422.
iron-based coatings have exhibited good mechanical properties, such as high hardness and good wear resistance, which are desirable properties in applications such as automobile brake rotors. iron-based coatings are also good replacements for Co- and Ni-based coatings, which are costly and could have health and environmental concerns due to their toxicity. In this research, three different iron-based coatings were deposited using the Detonation Gun Spraying (DGS) technology onto aluminum substrates, including the steel powders alone (unreinforced), and steel powders mixed with FeC and SiC particles, respectively. The microstructural characteristics of these coatings and mechanical properties, such as hardness and wear resistance, were examined. The morphology and structure of the feedstock powders were affected by the exposure to high temperature during the spraying process and rapid solidification of steel powders that resulted in the formation of an amorphous structure. While it was expected that steel particles reinforced with hard ceramic particles would result in increased hardness, instead, the unreinforced steel coating had the highest hardness, possibly due to a higher degree of amorphization in the coating than the other two. The microstructural observation confirmed the formation of dense coatings with good adhesion between layers. All samples were subjected to ball-on-disk wear tests at room temperature (23 °C) and at 200 °C. Similar wear resistances of the three samples were obtained at room temperature. At 200 °C, however, both ceramic reinforced composite samples exhibited higher wear rates in line with the reduction in their hardness values. This work explains, from the microstructural point of view, why adding hard particles to steel powers may not always lead to coatings with higher hardness and better wear resistance.
铁基涂层已表现出良好的机械性能，如高硬度和良好的耐磨性，这些都是汽车制动盘等应用中所需的性能。铁基涂层也是钴基和镍基涂层的良好替代品，钴基和镍基涂层成本高昂，且因其毒性可能存在健康和环境问题。在本研究中，使用爆轰枪喷涂（DGS）技术在铝基板上沉积了三种不同的铁基涂层，包括单独的钢粉（未增强）以及分别与FeC和SiC颗粒混合的钢粉。研究了这些涂层的微观结构特征以及硬度和耐磨性等机械性能。原料粉末的形态和结构受到喷涂过程中高温暴露以及钢粉快速凝固的影响，这导致了非晶结构的形成。虽然预计用硬陶瓷颗粒增强的钢颗粒会提高硬度，但相反，未增强的钢涂层硬度最高，这可能是因为该涂层的非晶化程度高于其他两种涂层。微观结构观察证实形成了层间附着力良好的致密涂层。所有样品均在室温（23°C）和200°C下进行了球盘磨损试验。在室温下，三个样品获得了相似的耐磨性。然而，在200°C时，两个陶瓷增强复合样品的磨损率都更高，这与它们硬度值的降低一致。这项工作从微观结构的角度解释了为什么向钢粉中添加硬颗粒不一定总能得到硬度更高、耐磨性更好的涂层。
