Investigation of the Mechanical Properties of Water-Soluble Salt Cores Produced by Binder Jetting Additive Manufacturing

Abstract Salt core is an environmentally alternative used to form cavities in molds and is easily cleaned after casting due to its water solubility. The production of salt cores with complex structures represents a challenging process when employing techniques based on traditional salt core production methods. In the traditional production methods, molten salt is either poured into the core mold and shaped or placed therein and compressed to a high degree of pressure. This study introduces a binder jetting approach to the production of water-soluble salt cores, offering a significant advancement in the field of salt core fabrication. This approach investigated the production of water-soluble salt cores utilizing binder jetting additive manufacturing technology. The binder was sodium silicate, and the matrix material was NaCl powder. The impact of binder rate (15%–20%–25%, according to NaCl ratio by weight) and sintering temperature (200 °C–275 °C–350 °C) on the compressive and flexural strength, solubility of salt cores was evaluated. In addition, the microstructural characteristics of the salt cores were examined by scanning electron microscopy. In this study, the binder content was determined to be 20 wt.%, and the sintering temperature and time were determined to be 200 °C and 180 min, respectively, to produce salt cores with a maximum compressive strength of 2.54 MPa, maximum flexural strength of 2.67 MPa, and water solubility value of 100.6 g/min·m 2 . The results of the study demonstrate that samples prepared under a range of parameters can be employed as cores in aluminum casting, particularly in permanent molds where pressure is elevated.