Development of a refractory mold based on chamotte/plaster for jewelry micro-casting with pre-set emeralds
During the jewelry stone-in-place micro-casting process, the ceramic mold, which is composed of silica and plaster is stabilized at temperatures close to 650 °C, whereas the casting temperature of the precious metal alloy hovers around 1000 °C. Therefore, this type of micro-casting technique is not...
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| Format: | Online |
| Language: | eng |
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Universidad Pedagógica y Tecnológica de Colombia
2017
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| Online Access: | https://revistas.uptc.edu.co/index.php/ingenieria/article/view/6421 |
| _version_ | 1801706078860214272 |
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| author | Londoño-Montes, Carlina Sofía Fernández-Torres, Mayerly Jhojana Córdoba-Tuta, Elcy María |
| author_facet | Londoño-Montes, Carlina Sofía Fernández-Torres, Mayerly Jhojana Córdoba-Tuta, Elcy María |
| author_sort | Londoño-Montes, Carlina Sofía |
| collection | OJS |
| description | During the jewelry stone-in-place micro-casting process, the ceramic mold, which is composed of silica and plaster is stabilized at temperatures close to 650 °C, whereas the casting temperature of the precious metal alloy hovers around 1000 °C. Therefore, this type of micro-casting technique is not suitable for gems such as emeralds, since they are highly susceptible to damage at temperatures over 350 °C. In the face of this fact, the main purpose of the present work is to develop a refractory mold based on chamotte and plaster, which can be stabilized at low temperatures, in order to use it for the micro-casting of pre-set emeralds. To achieve this, the experimental methodology was divided into three phases: i) raw chemical materials, mineralogical, granulometric and thermal characterization; ii) preparation and characterization of chamotte-plaster-water mixtures, including the measurement of casting times, mechanical and microstructural properties, permeability, and resistance to thermal shock; and iii) evaluation of the resulting refractory mold in the micro-casting of pre-set emeralds. The results showed that the refractory mold with composition chamotte/plaster 75/25, an addition of 50 % of water to the dried mixture, and fine granulometry (-200 mesh) had a stabilization temperature of 350 °C. Furthermore, it is possible to subject the emeralds to the stone-in-place micro-casting process that employs the refractory mold developed here, with a thermal treatment that does not surpass the 350 °C, along with a low melting point (398 °C) for the precious metal alloy. |
| format | Online |
| id | oai:oai.revistas.uptc.edu.co:article-6421 |
| institution | Revista Facultad de Ingeniería |
| language | eng |
| publishDate | 2017 |
| publisher | Universidad Pedagógica y Tecnológica de Colombia |
| record_format | ojs |
| spelling | oai:oai.revistas.uptc.edu.co:article-64212022-06-15T16:18:00Z Development of a refractory mold based on chamotte/plaster for jewelry micro-casting with pre-set emeralds Desarrollo de un revestimiento de chamota/yeso para microfundición de joyería con esmeraldas preengastadas Londoño-Montes, Carlina Sofía Fernández-Torres, Mayerly Jhojana Córdoba-Tuta, Elcy María Chamotte Emeralds Micro-Casting Plaster Refractory Mold Stone-In-Place Chamota Microfundición Molde refractario Preengaste de esmeraldas Yeso During the jewelry stone-in-place micro-casting process, the ceramic mold, which is composed of silica and plaster is stabilized at temperatures close to 650 °C, whereas the casting temperature of the precious metal alloy hovers around 1000 °C. Therefore, this type of micro-casting technique is not suitable for gems such as emeralds, since they are highly susceptible to damage at temperatures over 350 °C. In the face of this fact, the main purpose of the present work is to develop a refractory mold based on chamotte and plaster, which can be stabilized at low temperatures, in order to use it for the micro-casting of pre-set emeralds. To achieve this, the experimental methodology was divided into three phases: i) raw chemical materials, mineralogical, granulometric and thermal characterization; ii) preparation and characterization of chamotte-plaster-water mixtures, including the measurement of casting times, mechanical and microstructural properties, permeability, and resistance to thermal shock; and iii) evaluation of the resulting refractory mold in the micro-casting of pre-set emeralds. The results showed that the refractory mold with composition chamotte/plaster 75/25, an addition of 50 % of water to the dried mixture, and fine granulometry (-200 mesh) had a stabilization temperature of 350 °C. Furthermore, it is possible to subject the emeralds to the stone-in-place micro-casting process that employs the refractory mold developed here, with a thermal treatment that does not surpass the 350 °C, along with a low melting point (398 °C) for the precious metal alloy. Durante el proceso de microfundición de joyería con preengaste de gemas, el molde cerámico compuesto de sílice y yeso se estabiliza a temperaturas cercanas a 650 °C, mientras que la temperatura de vertido de la aleación preciosa ronda los 1000 °C. Por tal motivo, este método no es apropiado para gemas como la esmeralda, dada la gran susceptibilidad de esta al daño cuando se expone a temperaturas superiores a 350 °C. Teniendo en cuenta lo anterior, el objetivo del presente trabajo fue desarrollar un revestimiento cerámico de chamota-yeso que adquiera estabilidad dimensional a bajas temperaturas, con el fin de implementar el método de preengaste de esmeraldas para la obtención de piezas de joyería.La metodología experimental se dividió en tres etapas: i) caracterización química, mineralógica, granulométrica y térmica de las materias primas; ii) preparación y caracterización de las mezclas chamota-yeso-agua, incluyendo tiempos de vertido y fraguado de las pastas, junto a la permeabilidad y resistencia a la compresión y al choque térmico, y. además, análisis microestructural, y iii) evaluación del nuevo revestimiento en el proceso de microfundición con preengaste de esmeraldas. Se encontró que las condiciones más adecuadas para obtener el revestimiento chamota/yeso son: granulometría fina del refractario (100 % con pasante malla 200), relación chamota/yeso 75/25 y adición de 50 % de agua a la mezcla seca.Los resultados de la investigación permiten concluir que es posible someter las esmeraldas al proceso de microfundición de joyería, con gemas preengastadas, empleando el revestimiento chamota-yeso desarrollado aquí, cuyo tratamiento térmico no supera los 350 °C, así como una aleación de metal precioso de bajo punto de fusión (398 °C). Universidad Pedagógica y Tecnológica de Colombia 2017-04-30 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion investigation investigación application/pdf application/xml https://revistas.uptc.edu.co/index.php/ingenieria/article/view/6421 10.19053/01211129.v26.n45.2017.6421 Revista Facultad de Ingeniería; Vol. 26 No. 45 (2017); 121-135 Revista Facultad de Ingeniería; Vol. 26 Núm. 45 (2017); 121-135 2357-5328 0121-1129 eng https://revistas.uptc.edu.co/index.php/ingenieria/article/view/6421/5591 https://revistas.uptc.edu.co/index.php/ingenieria/article/view/6421/6412 |
| spellingShingle | Chamotte Emeralds Micro-Casting Plaster Refractory Mold Stone-In-Place Chamota Microfundición Molde refractario Preengaste de esmeraldas Yeso Londoño-Montes, Carlina Sofía Fernández-Torres, Mayerly Jhojana Córdoba-Tuta, Elcy María Development of a refractory mold based on chamotte/plaster for jewelry micro-casting with pre-set emeralds |
| title | Development of a refractory mold based on chamotte/plaster for jewelry micro-casting with pre-set emeralds |
| title_alt | Desarrollo de un revestimiento de chamota/yeso para microfundición de joyería con esmeraldas preengastadas |
| title_full | Development of a refractory mold based on chamotte/plaster for jewelry micro-casting with pre-set emeralds |
| title_fullStr | Development of a refractory mold based on chamotte/plaster for jewelry micro-casting with pre-set emeralds |
| title_full_unstemmed | Development of a refractory mold based on chamotte/plaster for jewelry micro-casting with pre-set emeralds |
| title_short | Development of a refractory mold based on chamotte/plaster for jewelry micro-casting with pre-set emeralds |
| title_sort | development of a refractory mold based on chamotte plaster for jewelry micro casting with pre set emeralds |
| topic | Chamotte Emeralds Micro-Casting Plaster Refractory Mold Stone-In-Place Chamota Microfundición Molde refractario Preengaste de esmeraldas Yeso |
| topic_facet | Chamotte Emeralds Micro-Casting Plaster Refractory Mold Stone-In-Place Chamota Microfundición Molde refractario Preengaste de esmeraldas Yeso |
| url | https://revistas.uptc.edu.co/index.php/ingenieria/article/view/6421 |
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