Full text
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| Author(s): |
Rayander Martins Pimenta
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Lorena. |
| Institution: | Universidade de São Paulo (USP). Escola de Engenharia de Lorena (EEL/ASDI) |
| Defense date: | 2023-04-06 |
| Examining board members: |
Carlos Angelo Nunes;
Haroldo Cavalcanti Pinto;
Geovani Rodrigues
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| Advisor: | Carlos Angelo Nunes; Nabil Chaia |
| Abstract | |
This work has as objective the application of aluminum-based coatings to improve the corrosion resistance of the cleaning tips of Kraft recovery boilers, whose function is to clear the air flow doors. The process adopted for the manufacturing of the coatings was the Halide Activated Pack Cementation (HAPC). The coated samples were analyzed by optical microscopy (OM) and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and Vickers microhardness. The aluminization processes were employing as donor a Fe-Al alloy for low activity experiments and pure Al for high activity experiments. The inert filler responsible for the dilution of the powder mixture was Al2O3. The transport in the gas phase of the coating-forming elements was ensured by the NH4Cl halide. The kinetics of the carburizing process was determined through changes in temperature and residence time in the furnace. In this work, the aluminization was performed on an AISI 304L stainless steel substrate and the morphology of the cross section was analyzed at 850, 900 and 950 °C for 4, 9 and 16h, for the experiments at low activity. For the experiments at high activity, the morphology of the cross section was analyzed at 700 and 800 °C for 4, 9 and 16h. Also, the growth kinetics of the coating was studied, which indicated a parabolic growth. For the experiments at low activity the growth constants varied between 0 and 3.10-8 cm2.s-1 and for the experiments at high activity the constants varied between 0 and 9.10-8 cm2.s-1. The hardness values measured in the layers were higher than that of the substrate, being approximately between 2 and 4 higher. (AU) | |
| FAPESP's process: | 21/03250-4 - Application of the pack cementation process aiming to increase resistance to corrosion and oxidation of cleaning component used in kraft recovery boiler |
| Grantee: | Rayander Martins Pimenta |
| Support Opportunities: | Scholarships in Brazil - Master |