Humidity Migration in Surface Layers of Sand Moulds During Processes of Penetration and Drying of Protective Coatings

• Autorzy: Jamrozowicz Łukasz , Zych Jerzy

Identyfikatory

DOI

10.24425/afe.2022.143952

• Języki publikacji: EN

Abstrakty

EN

The results of investigations of humidity migration in near surface layers of sand mould during processes of penetration and drying of protective coatings are presented in the hereby paper. The process of the humidity exchanging between surroundings and moulding sands as porous materials, is widely described in the introduction. In addition, the humidity flow through porous materials, with dividing this process into stages in dependence of the humidity movement mechanism, is presented. Next the desorption process, it means the humidity removal from porous materials, was described. Elements of the drying process intensity as well as the water transport mechanisms at natural and artificial drying were explained. The innovative research stands for measuring resistance changes of porous media due to humidity migrations was applied in investigations. Aqueous zirconium coatings of two apparent viscosities 10s and 30s were used. Viscosity was determined by means of the Ford cup of a mesh clearance of 4mm. Coatings were deposited on cores made of the moulding sand containing sand matrix, of a mean grain size dL = 0.25 mm, and phenol-formaldehyde resin. Pairs of electrodes were placed in the core at depths: 2, 3, 4, 5, 8, 12 and 16 mm. Resistance measurements were performed in a continuous way. The course of the humidity migration process in the core surface layer after covering it by protective coating was determined during investigations. Investigations were performed in the room where the air temperature was: T = 22^oC but the air humidity was not controlled, as well as in the climatic chamber where the air temperature was: T =35^oC and humidity: H = 45%. During the research, it was shown that the process of penetration (sorption) of moisture into the moulding sand is a gradual process and that the moisture penetrates at least 16 mm into the sand. In the case of the drying (desorption) process, moisture from the near-surface layers of the moulding sand dries out much faster than moisture that has penetrated deeper into the sand.

Słowa kluczowe

EN

surface layers; sand mould; porous medium; humidity migration; protective coatings; resistance measurement

PL

warstwy powierzchniowe; formy piaskowe; migracja wilgoci; powłoki ochronne; pomiar rezystancji

• Wydawca: Komisja Odlewnictwa Polskiej Akademii Nauk Oddział w Katowicach
• Czasopismo: Archives of Foundry Engineering
• Rocznik: 2022
• Tom: Vol. 22, iss. 4
• Strony: 72--78
• Opis fizyczny: Bibliogr. 25 poz., il., wykr.

Twórcy

autor

Jamrozowicz Łukasz

• AGH University of Science and Technology, Faculty of Foundry Engineering, Kraków, Poland

• https://orcid.org/0000-0002-0499-7851

autor

Zych Jerzy

• AGH University of Science and Technology, Faculty of Foundry Engineering, Kraków, Poland

• https://orcid.org/0000-0003-3067-4316

Bibliografia

• [1] Pigoń, K., Ruziewicz, Z. (2005). Physical chemistry. Phenomenological foundations. Warszawa: PWN, (in Polish).
• [2] Zarzycki, R. (2005). Heat transfer and mass movement in environmental engineering. Warszawa: Wydawnictwo Naukowo-Techniczne. (in Polish)
• [3] Płoński, W., Pogorzelski, J. (1979). Building physics. Warszawa: Arkady. (in Polish).
• [4] Świrska-Perkowska, J. (2012). Adsorption and movement of moisture in porous building materials under isothermal conditions. Warszawa: Komitet Inżynierii Lądowej i Wodnej PAN. (in Polish).
• [5] Kubik, J. (2000). Moisture flows in building materials. Opole: Oficyna Wydawnicza Politechniki Opolskiej. (in Polish).
• [6] Gawin, D. (2000). Modeling of coupled hygrothermal phenomena in building materials and elements. Łódź: Politechnika Łódzka. (in Polish).
• [7] Rose, D. (1963). Water movement in porous materials. Part 1: isothermal vapour transfer. British Journal of Applied Physics. (14), 256-262. DOI:10.1088/0508-3443/14/5/308.
• [8] Rose, D. (1963): Water movement in porous materials. part 2: the separation of the components of water movement. British Journal of Applied Physics. (14), 491-496. DOI: 10.1088/0508-3443/14/8/310.
• [9] Marynowicz, A., Wyrwał, J. (2005). Testing the moisture properties of selected building materials under isothermal conditions. Warszawa: INB ZTUREK. (in Polish).
• [10] Kiessl, K. (1983) Kapillarer und dampffoermiger Fauchtetransport in mahrschichtigen Bauteilen. Essen: Dissertation. University Essen.
• [11] Politechnika Gdańska. The process of drying food substances - laboratory exercises. Retrieved January, 2022, from https://mech.pg.edu.pl/documents/4555684/4565480/suszenie.pdf (in Polish).
• [12] Baranowski, J., Melech, S., Adamski, P. (2002). Temperature and humidity control systems in the processes of drying food products. Zielona Góra: VI Sympozjum Pomiary i Sterowanie w Procesach Przemysłowych. (in Polish)
• [13] Ważny, J., Karyś, J. (2001). Protection of buildings against biological corrosion. Warszawa: Arkady. (in Polish)
• [14] Brooker, D., Bakker-Arkema, F., Hall, C. (1992). Drying and Storage of Grains and Oilseeds. New York: Van Nostrand Reinhold.
• [15] Reeds, J. (1991). Drying. ASM International Handbook Committee. 131-134.
• [16] Pel, L., Sawdy, A. & Voronina, V. (2010). Physical principles and efficiency of salt extraction by poulticing. Journal of Cultural Heritage. 11(1), 59-67. DOI:10.1016/j.culher.2009.03.007.
• [17] Hii, C., Law, C. & Cloke, M. (2008). Modelling of thin layer drying kinetics of cocoa beans during artificial and natural drying. Journal of Engineering Science and Technology. 3(1),1-10.
• [18] Zych, J. & Kolczyk, J. (2013). Kinetics of hardening and drying of ceramic moulds with the new generation binder – colloidal silica. Archives of Foundry Engineering. 13(4), 112-116. DOI: 10.2478/afe-2013-0093.
• [19] Kolczyk J. & Zych J. (2014). The kinetics of hardening and drying of ceramic molds with a new generation binder -colloidal silica. Przegląd Odlewnictwa. 64(3-4), 84-92. (In Polish).
• [20] Zych, J., Kolczyk, J. & Jamrozowicz, Ł. (2015). The influence of the shape of wax pattern on the kinetics of drying of ceramic moulds. Metalurgija. 54(1), 15-18. ISSN 0543-5846.
• [21] Jamrozowicz, Ł., Zych, J. & Kolczyk, J. (2015). The drying kinetics of protective coatings used on sand molds. Metalurgija. 54(1), 23-26. ISSN 0543-5846.
• [22] Jamrozowicz, Ł. & Siatko, A. (2020). The assessment of the permeability of selected protective coatings used for sand moulds and cores. Archives of Foundry Engineering. 20(1), 17-22. DOI: 10.24425/afe.2020.131276.
• [23] Jamrozowicz, Ł., Kolczyk-Tylka, J. & Siatko, A. (2018) Investigations of the thickness of protective coatings deposited on moulds and cores. Archives of Foundry Engineering. 18(4), 131-136. DOI: 10.24425/afe.2018.125182.
• [24] Zych, J. & Snopkiewicz, T. (2010). Drying and hardening of ceramic moulds used in a modern investemnt casting technique – investigations of the process kinetics. Foundry Journal of the Polish Foundrymen's Association. 9-10, 506-512.
• [25] Zych, J., Snopkiewicz, T. (2018). Method for study the drying process self-hardening molding sand or core compound. Patent PL 228373 B1.

Uwagi

Opracowanie rekordu ze środków MEiN, umowa nr SONP/SP/546092/2022 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2022-2023)