## 1 Introduction  
Metal-injection molding (MIM) is a process used to obtain complex net shape components with accurate final tolerances and surface roughness [1; 2]. It consists of preparing high-loaded mixtures with metallic powders (feedstock) and thermoplastic polymers (multi-component binder). The feedstock undergoes three stages: injection molding, debinding, and sintering [3]. The MIM process presents some interesting properties for the industrial mass production of complex-shaped components. The feedstock behavior (binder-weight fraction, powder-volume loading, critical-volume loading, chemical composition, shear-viscosity behavior, etc.) has an important influence on the final components [4]. Therefore, as important features of the process, the mixing conditions and thermal-physical characteristics must be identified [5]. The binder must support the powder load and carry the powder into the mold cavity during the injection-molding step [6]. It should interact well with the metal powders [5]. Then, the binder is removed during the debinding step, and finally sintered by solid-state diffusion of the powder to obtain the final dense metallic component, which has mechanical properties similar to those of a wrought material [7]. The debinding stage, corresponding to the extraction of the binder, is probably the most time-consuming step. In addition, it is difficult to completely remove the binder without introducing defects into the component [8]. Different methods can be used to accomplish the debinding process [9; 10]. The most common debinding techniques are thermal debinding [11], catalytic debinding [12], and solvent debinding [13]. Catalytic debinding focuses on a solid-to-vapor catalytic degradation, e.g., exposing an acetyl-based component to acid vapors [12]. It results in a much faster binder removal and a higher handling strength than thermal debinding [14]. However, this method can affect the chemical properties of the powder skeleton. Thermal debinding involves the oxidation of the binder in air, or pyrolysis in nitrogen [9]. During thermal debinding, the component is heated until the degradation temperature of the main binder (backbone). The advantage of this process is that the main binder is removed without disrupting the packing of the powder particles. However, if the binder oxidation is incomplete, the residue may affect the final properties of the component [15]. Moreover, the high debinding stress can affect the final shape. To reduce defects during this step, some alternative methods have been developed. Solvent debinding consists of extracting a soluble binder by immersing the component in a solvent (e.g., water or ethanol) before the thermal debinding [6; 16; 17; 18]. Organic solvents are commonly used and have the advantages of shape retention and rapid debinding [8]. However, water is often used because it is less pollutant and more economic. However, the diffusion time of a soluble binder during water debinding is much longer. A shorter and innovative method for extracting an organic binder is to use supercritical fluid debinding [19; 20; 21; 22]. Supercritical debinding was reported by [PERSON] et al. [23] in 1995 on ceramic-powder components. It has proven to be a useful alternative to solvent debinding; it reduces the debinding time and eliminates defects in green-body components [22]. Carbon dioxide is the most used fluid because it is very effective and environmentally friendly [19]. Nevertheless, during supercritical debinding, the component is subjected to high pressure, which can cause additional shrinkage. The main goal of these methods is to make the component porous before the thermal degradation of the binder. The relevant properties of a supercritical fluid are the density, the viscosity, the mass diffusivity, and the thermal conductivity, as reported by [PERSON] et al. [24]. These properties can be easily controlled by the pressure and the temperature of the supercritical fluid.