Powder Injection Molding of Ceria-Stabilized, Zirconia-Toughened Mullite Parts for UAV Engine Components

Abstract

Powder injection molding (PIM) of ceria-stabilized, zirconia-toughened mullite composites were investigated in the present article with the goal of obtaining performance enhancement in complex geometries for energy and transportation applications. A powder-polymer mixture (feedstock) was developed and characterized to determine its suitability for fabricating complex components using the PIM process. Test specimens were injection molded and subsequently debound and sintered. The sintered properties indicated suitable properties for engine component applications used in unmanned aerial vehicles (UAVs). The measured feedstock properties were used in computer simulations to assess the mold-filling behavior for a miniature turbine stator. The results from the measurements of rheological and thermal properties of the feedstock combined with the sintered properties of the ceria-stabilized, zirconia-toughened mullite strongly indicate the potential for enhancing the performance of complex geometries used in demanding operating conditions in UAV engines.

Sintering Characteristics of a Powder Injection Molded Ceria-Stabilized Zirconia–Mullite Composite

“…Figure 1(a) shows a typical target geometry of a UAV stator to be fabricated by PIM. Figure 1(b) demonstrates the feasibility of the geometry to be fabricated using mold-filling simulations based on measured feedstock data in the prior study [21]. Such part geometry is clearly impossible to fabricate by simple uniaxial compaction and is hard to achieve large production volumes by cold isostatic pressing and sintering.…”

“…The ability of PIM technology to successfully fabricate zirconia-mullite parts without formation of defects was studied. Our prior publication discusses the successful development and characterization of zirconia-mullite feedstock for injection molding [21]. The powder-polymer mixture properties were used to successfully simulate the mold-filling behavior of the material for fabricating UAV engine components using PIM.…”

“…A standard wax-polymer mixture was used as a binder system in the present study. The details regarding the preparation and characterization of feedstock for various properties are published elsewhere [21,22]. Test samples were molded on an injection molding machine (Arburg) at Kinetics Corporation (Wilsonville, OR).…”

Process parameter optimization of plastic injection molding: a review

“…Numerous works using such software packages have been reported, e.g., Moldflow ® in the fabrication of window frames using rice husk filled polyethylene composites [94], Moldflow ® combined with Autodesk Inventor r for modeling and simulating shallow and flat thin walled molds of a polymer composite [5,6], Moldflow ® to determine significant parameters affecting the shrinkage of molded components [69], Moldflow ® to study material distribution and melt flow behaviour in sandwich molding process [92], Moldflow ® combined with the Taguchi method to determine the optimal design parameters by minimizing the warpage of gas assisted molding components [14], and Moldflow ® integrated with the Taguchi method to study the effects of processing parameters on the molding of ultra-thin wall polymer components [102]. Apart from that, Moldflow ® was applied to some other similar works also, e.g., simulation of feedstock properties for powder injection molding of thermal management devices [86], feedstock properties and injection molding simulations of bimodal mixtures [49], measurements of powder-polymer mixture properties and their use in powder injection molding simulations [48], powder injection molding of ceramic engine components for transportation [61], effects of nanoparticle addition on processing of alloys [85], powder injection molding of parts for UAV engine components [74], etc.…”