## 4 Conclusions  
This study investigated the effect of using a unique binder formulation on the rheological, density, oxygen, and carbon contamination and the magnetic properties of Ce-substituted Nd-Fe-B feedstocks. The LLDPE backbone content ranged from 35-52.5 vol.%, the PW soluble component from 41.25 to 60 vol.%, and the SA surfactant content from 5 to 8.75 vol.% in the binder system, and the powder loadings between 55 and 60 vol.% were used to understand the impact of the binder formulation on the rheology, density, and magnetic properties of MIM feedstocks. The results demonstrated that a 52.5 vol.% LLDPE backbone content in the binder system results in high viscosity and pressure; however, a 35 vol.% backbone reduces the processability because the extremely low viscosity leads to unstable pressure. However, the rheological results showed that the pressure variation for the binder formulation with the 45 vol.% LLDPE was low, which can be concluded that this binder had a proper flow behavior for the MIM process. The viscosity results for the powder loadings of 55, 57, 58, 59, and 60 vol.% with the binder formulation containing 45 vol.% LLDPE revealed that the viscosity of 60 vol.% was higher than the recommended viscosity of 1000 Pa-s. The feedstock with 58 vol.% powder had acceptable pressure stability at the measured shear rates. In addition, the flow index n of the feedstock with 58 vol.% was the highest; therefore, this feedstock is more suitable for the MIM process since it has the best flow behavior.  
The physical characteristics of sintered parts for different feedstock formulations complemented the results of the rheological properties. A high density of 6.83 g/cm\({}^{3}\)  
Figure 7: Representative values for magnetic properties of the feedstock formulation of B at different powder content.  
the remanence (Br) of 0.591 T, and the coercivity (Hcj) of 744.6 kA/m were obtained for feedstocks having the best rheological behavior. Increasing the powder loading to 58 vol.% decreased the porosity to 0.7% and increased the density to 7.54 g/cm\({}^{3}\). Although the feedstock with 59 vol.% solid loading has the highest magnetic properties, the 58 vol.% powder loading was considered the optimized formulation due to having better flowability and homogeneity. Therefore, the binder system components significantly influence the magnetic properties of MIM magnets, and a tailored formulation can be used to maximize their magnetic properties.  
V.M. and S.L.: conception, experimental design, carrying out measurements and manuscript composition; J.G.-G.: conception and manuscript composition; S.C.: experimental design and manuscript composition; E.S.: carrying out measurements; Z.S.: manuscript composition; S.S.: manuscript composition; C.K.: manuscript composition; C.H.: manuscript composition. All authors have read and agreed to the published version of the manuscript.  
This research was supported under Project Agreement No. 19120 and has received funding from the European Institute of Innovation and Technology (EIT), a body of the European Union, under the Horizon 2020, the EU framework program for research and innovation.  
Not applicable.  
The data that support the findings of this study will be available on request.  
The authors declare no conflicts of interest.