TY - JOUR A1 - Frunzaverde, Doina A1 - Marginean, Gabriela A1 - Ciubotariu, Costel-Relu T1 - Corrosion and Cavitation Performance of Flame-Sprayed NiCrBSi Composite Coatings Reinforced with Hard Particles JF - Crystals (Special Issue Modern Technologies in the Manufacturing of Metal Matrix Composites) N2 - To enhance the operational life of hydraulic machinery, protective coatings against wear, particularly cavitation erosion, and corrosion might be applied on the surfaces of components. The experiments conducted in this study aimed to assess the suitability of 80/20 NiCrBSi/WC-Co composite coatings for this purpose. A coating of NiCrBSi self-fluxing alloy, which served as the reference material, was deposited alongside a NiCrBSi coating reinforced with 20% WC-Co, both applied by flame spraying onto X3CrNiMo13-4 substrates, the martensitic stainless steel type frequently utilized in turbine blade manufacturing. The improved density of the coatings and adhesion to the substrate was achieved by remelting with an oxyacetylene flame. The cavitation and corrosion performance of both the reference and composite coating were evaluated through cavitation tests and electrochemical measurements conducted in the laboratory. The results demonstrate that the addition of 20% WC-Co significantly enhances the cavitation resistance of the composite material, as evidenced by the reduction to 3.76 times of the cumulative erosion (CE), while the stabilization rate remained at half the value observed for the reference self-fluxing alloy coating. Conversely, the addition of WC-Co into the NiCrBSi coating resulted in a slight decrease in the corrosion resistance of the self-fluxing alloy. Nevertheless, the corrosion rate of the composite coating (124.80 µm/year) did not significantly exceed the upper limit for excellent corrosion resistance (100 µm/year). KW - cavitation resistance KW - corrosion resistance KW - coatings KW - hydraulic machinery KW - self-fluxing alloys KW - NiCrBSi KW - WC-12Co KW - NiCrBSi/WC-Co composites Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1010-opus4-47740 SN - 2073-4352 VL - 2024 IS - 14 (12) SP - 1 EP - 12 PB - MDPI ER - TY - JOUR A1 - Ciubotariu, Costel-Relu A1 - Frunzaverde, Doina A1 - Marginean, Gabriela T1 - Investigations of Cavitation Erosion and Corrosion Behavior of Flame-Sprayed NiCrBSi/WC-12Co Composite Coatings JF - Materials MDPI N2 - 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 (icorr). 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. KW - corrosion KW - self-fluxing alloys KW - NiCrBSi KW - WC-12Co KW - cavitation KW - hard metals Y1 - 2022 U6 - https://doi.org/10.3390/ma15082943 VL - 2022 IS - 15 SP - 2943 ER -