Review: Thermal Debinding Process in Particulate Materials Processing

Abstract

Developing a rapid and efficient method for removing polymers (termed binders) from a shaped powder component, know as a green body, is important to forming defect-free metal, ceramic, and cermet structures. The rapid growth in powder injection molding to form complex shapes at high precision in large quantities has increased the need for faster, cleaner, and cheaper polymer removal processes. Binder removal using controlled heating of the component in gaseous atmosphere is the most popular method. This thermal debinding or burnout process is a delicate process, since it is easy to crack, blister, slump, or otherwise damage the component with an improperly designed cycle. To avoid these issues, often long heating cycles are used to remove the binder, but with a loss of productivity. Considerable progress has been made over the past several decades in understanding various phenomena during polymer burnout, resulting in substantial reduction in the thermal debinding time. This article provides an overview of the research carried out on thermal debinding process (primarily from powder injection molded samples) with major emphasis on progress reported over the last fifteen years. This review article proposes a model to predict the formation of defects during all stages of thermal debinding and suggests future research direction in the field.

Additive Manufacturing of Metallic and Ceramic Components by the Material Extrusion of Highly-Filled Polymers: A Review and Future Perspectives

“…The part with the lower of soluble binder removal had bubbles at the center (left). Bloating of specimens due to incomplete debinding is a common defect in PIM [ 143 ]. The cause of this defect is the vapor formed during the degradation of the polymers.…”

“…The cause of this defect is the vapor formed during the degradation of the polymers. In the areas rich in binder, this vapor cannot be easily evacuated and when the partial pressure of the trapped vapor is higher than the atmospheric pressure the bubbles appear [ 143 ]. Therefore, the creation of a porous structure by the removal of the soluble component is critical for the following thermal debinding step [ 62 ].…”

Near‐Net‐Shaping Methods for Ceramic Elements of (Body) Armor Systems

“…High volume fraction of organic materials must be removed from the ceramic compact without creating cracks, distortion or voids. In general, the organic materials are removed by a slow volatilization at elevated temperature . The typical temperature for binder burn‐out is 400°C, but this may vary depending on the type and composition of the binder.…”

Study of a New Method to Fabricate W–Cu Composites

“…However, the distinct difference in melting point and the insolubility between W and Cu make it difficult to prepare W-Cu composites. Many methods of preparing W-Cu composites have been developed, including laser sintering, infiltration method, resistance sintering, mechanical alloying, activated sintering, liquid-phase sintering and plasma spraying [2][3][4][5][6][7][8][9].…”