Physical property of 925 sterling silver metal injection molding and morphology of brown parts under varying solvent-based debinding conditions

Abstract

This research aims to study the physical properties of raw parts produced using Metal Injection Molding (MIM), an advanced manufacturing process suitable for the industrial-scale production of highly complex, small, and high-precision three-dimensional metal parts. However, applying this technique to precious metals, especially 925 sterling silver, still has significant limitations and research gaps, particularly regarding the use of atomized metal powders, which are a byproduct and have lower costs than general-purpose specialized metal powders. 925 silver feedstock used to produce the MIM samples consisted of 90% 925 silver powder and 10% binder. Solvent-based binder removal was performed in water for 5 hours at three temperatures: 30°C, 40°C, and 50°C, respectively. Microstructure and particle morphology were examined using a scanning electron microscope (SEM). The goal was to identify the optimal conditions for forming an open porous structure conducive to sintering and shape retention in subsequent industrial processes. The experimental results showed that the optimal material ratio consisted of 90% silver powder and 10% binder by weight, resulting in an average material density of 4.507 g/cm³ and an average material tensile strength of 17.70 MPa. The results indicated that the binder removal process using distilled water at 50°C for 5 hours was the most efficient method.