Ciubotariu Costel-Relu, Frunzaverde Doina, Marginean Gabriela
Department of Engineering Science, Faculty of Engineering, Babeș-Bolyai University, Square Traian Vuia 1-4, 320085 Resita, Romania.
Department of Materials Science and Testing, Westphalian University of Applied Sciences Gelsenkirchen Bocholt Recklinghausen, Neidenburger Str. 43, 45897 Gelsenkirchen, Germany.
Materials (Basel). 2022 Apr 18;15(8):2943. doi: 10.3390/ma15082943.
Flame-sprayed NiCrBSi/WC-12Co composite coatings were deposited in different ratios on the surface of stainless steel. Oxyacetylene flame remelting treatment was applied to surfaces for refinement of the morphology of the layers and improvement of the coating/substrate adhesion. The performance of the coated specimens to cavitation erosion and electrochemical corrosion was evaluated by an ultrasonic vibratory method and, respectively, by polarization measurements. The microstructure was investigated by means of scanning electron microscopy (SEM) combined with energy dispersive X-ray analysis (EDX). The obtained results demonstrated that the addition of 15 wt.% WC-12Co to the self-fluxing alloy improves the resistance to cavitation erosion (the terminal erosion rate (Vs) decreased with 15% related to that of the NiCrBSi coating) without influencing the good corrosion resistance in NaCl solution. However, a further increase in WC-Co content led to a deterioration of these coating properties (the Vs has doubled related to that of the NiCrBSi coating). Moreover, the corrosion behavior of the latter composite coating was negatively influenced, a fact confirmed by increased values for the corrosion current density (i). Based on the achieved experimental results, one may summarize that NiCrBSi/WC-Co composite coatings are able to increase the life cycle of expensive, high-performance components exposed to severe cavitation conditions.
采用火焰喷涂工艺，以不同比例在不锈钢表面沉积了NiCrBSi/WC - 12Co复合涂层。对涂层表面进行氧乙炔火焰重熔处理，以细化涂层形貌并提高涂层与基体之间的附着力。分别采用超声振动法和极化测量法对涂层试样的抗空蚀性能和电化学腐蚀性能进行了评估。借助扫描电子显微镜（SEM）结合能量色散X射线分析（EDX）对微观结构进行了研究。所得结果表明，在自熔合金中添加15 wt.%的WC - 12Co可提高抗空蚀性能（终态侵蚀速率（Vs）相对于NiCrBSi涂层降低了15%），且不影响在NaCl溶液中的良好耐蚀性。然而，WC - Co含量的进一步增加会导致这些涂层性能的恶化（Vs相对于NiCrBSi涂层增加了一倍）。此外，后一种复合涂层的腐蚀行为受到负面影响，这一事实通过腐蚀电流密度（i）值的增加得到证实。基于所取得的实验结果，可以总结出NiCrBSi/WC - Co复合涂层能够延长暴露在严重空蚀条件下的昂贵高性能部件的使用寿命。
