Humidity Migration in Surface Layers of Sand Moulds During Processes of Penetration and Drying of Protective Coatings
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...
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| Format: | Article |
| Language: | English |
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Polish Academy of Sciences
2022-12-01
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| Series: | Archives of Foundry Engineering |
| Subjects: | |
| Online Access: | https://journals.pan.pl/Content/125439/PDF/AFE%204_2022_10_final.pdf |
| _version_ | 1797804135511228416 |
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| author | Ł. Jamrozowicz J. Zych |
| author_facet | Ł. Jamrozowicz J. Zych |
| author_sort | Ł. Jamrozowicz |
| collection | DOAJ |
| description | 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˚C but the air humidity was not controlled, as well as in the climatic chamber where the air temperature was: T = 35˚C 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. Keywords: Core, Sand mould, Porous medium, Humidity migration, Protective coatings, Resistance measurement |
| first_indexed | 2024-03-13T05:32:36Z |
| format | Article |
| id | doaj.art-728e00ff3ccf460796d127ee8fe6390b |
| institution | Directory Open Access Journal |
| issn | 2299-2944 |
| language | English |
| last_indexed | 2024-03-13T05:32:36Z |
| publishDate | 2022-12-01 |
| publisher | Polish Academy of Sciences |
| record_format | Article |
| series | Archives of Foundry Engineering |
| spelling | doaj.art-728e00ff3ccf460796d127ee8fe6390b2023-06-14T15:23:54ZengPolish Academy of SciencesArchives of Foundry Engineering2299-29442022-12-01vol. 22No 47278https://doi.org/10.24425/afe.2022.143952Humidity Migration in Surface Layers of Sand Moulds During Processes of Penetration and Drying of Protective CoatingsŁ. Jamrozowicz0https://orcid.org/0000-0002-0499-7851J. Zych1https://orcid.org/0000-0003-3067-4316AGH University of Science and Technology, Faculty of Foundry Engineering, Department of Moulding Materials, Mould Technology and Cast Non-Ferrous Metals, Al. Mickiewicza 30, 30-059 Kraków, PolandAGH University of Science and Technology, Faculty of Foundry Engineering, Department of Moulding Materials, Mould Technology and Cast Non-Ferrous Metals, Al. Mickiewicza 30, 30-059 Kraków, PolandThe 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˚C but the air humidity was not controlled, as well as in the climatic chamber where the air temperature was: T = 35˚C 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. Keywords: Core, Sand mould, Porous medium, Humidity migration, Protective coatings, Resistance measurementhttps://journals.pan.pl/Content/125439/PDF/AFE%204_2022_10_final.pdfcoresand mouldporous mediumhumidity migrationprotective coatingsresistance measurement |
| spellingShingle | Ł. Jamrozowicz J. Zych Humidity Migration in Surface Layers of Sand Moulds During Processes of Penetration and Drying of Protective Coatings Archives of Foundry Engineering core sand mould porous medium humidity migration protective coatings resistance measurement |
| title | Humidity Migration in Surface Layers of Sand Moulds During Processes of Penetration and Drying of Protective Coatings |
| title_full | Humidity Migration in Surface Layers of Sand Moulds During Processes of Penetration and Drying of Protective Coatings |
| title_fullStr | Humidity Migration in Surface Layers of Sand Moulds During Processes of Penetration and Drying of Protective Coatings |
| title_full_unstemmed | Humidity Migration in Surface Layers of Sand Moulds During Processes of Penetration and Drying of Protective Coatings |
| title_short | Humidity Migration in Surface Layers of Sand Moulds During Processes of Penetration and Drying of Protective Coatings |
| title_sort | humidity migration in surface layers of sand moulds during processes of penetration and drying of protective coatings |
| topic | core sand mould porous medium humidity migration protective coatings resistance measurement |
| url | https://journals.pan.pl/Content/125439/PDF/AFE%204_2022_10_final.pdf |
| work_keys_str_mv | AT łjamrozowicz humiditymigrationinsurfacelayersofsandmouldsduringprocessesofpenetrationanddryingofprotectivecoatings AT jzych humiditymigrationinsurfacelayersofsandmouldsduringprocessesofpenetrationanddryingofprotectivecoatings |