Freeze Casting Research Articles

Hierarchical porous SiCnws/SiC composites with one-dimensional oriented assemblies for high-temperature broadband wave absorption

The research on high-performance electromagnetic wave absorption materials with high-temperature and oxidative stability in extreme environments is gaining popularity. Herein, the lightweight silicon carbide nanowires (SiCnws)/SiC composites are fabricated with in-situ SiC interface on one-dimensional oriented SiCnws skeleton, which collaborative configuration by 3D printing and freeze casting assembly. The constructed porous structure optimizes the impedance matching degree and scattering intensity, the maximum effective absorption bandwidth (EABmax) of 5.9 GHz and the minimum reflection loss (RLmin) of −41.4 dB can be realized. Considering the inherent oxidation resistance of SiC, the composites present well-maintained absorption performance at 600 °C. Even at 1100 °C, the EABmax of 4.9 GHz and RLmin of −30.4 dB also demonstrate the high-temperature absorption stability of the composites, indicating exceptional wave absorption properties and thermal stability. The slight attenuation can be attributed to the decrease in impedance matching capability accompanying the elevated dielectric constant. This work clarifies the impact of structure and component synergy on wave absorption behavior, and offers a novel approach to producing high-performance and high-temperature resistance ceramic-based electromagnetic wave absorption materials suitable for extreme environments.

Construction of multi-interface magnetic FeMnC modified carbon/graphene aerogels for broadband microwave absorption

Magnetic carbon-based aerogels with low-density and strong attenuation, have attracted significant attention as microwave absorbing materials, but still face huge challenges. Herein, magnetic FeMnC modified carbon/Graphene aerogels (NCMF) were synthesized utilizing freeze casting following a carbothermal reduction process. The conductivity, defects density, material component and electromagnetic properties can be regulated by the temperature. The NCMF aerogels exhibit remarkable microwave absorption properties, with an effective absorption bandwidth of 5.76 GHz at a thickness of 2.1 mm and a minimum reflection loss as low as −50.8 dB at 7.52 GHz with a fill ratio of only 5 wt%. The exceptional microwave absorption capabilities of NCMF aerogels are attributed to the synergistic effects of dielectric loss, magnetic loss, three-dimensional (3D) carbon conductive network, and the optimal impedance matching. Consequently, this research paves a way for the development of microwave absorbing materials with lightweight, broadband and strong microwave absorption at low loading.

Eco-friendly MXene/enteromorpha prolifera biomass aerogel with excellent photothermal conversion and flame retardant properties for efficient separation of viscous oil/seawater mixture

Traditional adsorbents are often ineffective in cleaning up high-viscosity oil spills that cause harm to the marine environment. An efficient, safe and eco-friendly solution is urgently needed. Here, we prepare a superhydrophobic MXene/gelatin-enteromorpha prolifera biomass aerogel (H-MXene/G-EP) with excellent photothermal conversion and flame retardancy for solar-driven remediation of high-viscosity oil spills. The short-range aligned multidomain lamellar structure constructed through unidirectional freeze casting endows H-MXene/G-EP with compressibility and an adsorption capacity (63.7 g/g). Due to the excellent light responsiveness and full-spectrum high absorption of H-MXene/G-EP, it can reach a surface temperature 71.6 °C under 1 Sun (1.0 kW/m2), and an in-situ adsorption rate 367.40 g/h for viscous crude oil. The efficiency of separating O/W emulsions is up to 99.1%, which greatly broadens the range of applications for oil/water separation technology. Furthermore, the H-MXene/G-EP exhibits excellent flame retardancy, reducing the heat release rate by 89.59% and the total smoke production rate by 47.83%, respectively. This effectively reduces the probability of secondary marine fires. Thus, this novel biomass-derived aerogel provides a feasible and environmentally friendly solution for effective remediation of marine oil spills.

Bone-inspired AZ31/HA composites with gradient structures and properties for implant applications

The increasing demand for lightweight, damage-resistant, wear-resistant, and corrosion-resistant materials in implant applications has driven the development of novel bone-inspired composites. This study introduces AZ31 (Mg–3Al–1Zn)/hydroxyapatite (HA) composites fabricated using centrifugal freeze casting and pressureless infiltration. The unique formation mechanism and structure-property relationship of these composites were investigated. The gradient distribution of HA particles and the nucleation and growth behavior of ice crystals, influenced by varying solid content in the centrifugal field, resulted in a radially increasing ceramic-layer-to-metal-layer thickness ratio. Consequently, the composites exhibited a gradient distribution of compression strength, hardness, wear resistance, and corrosion resistance. Moreover, the composites showed no cytotoxicity and promoted osteoblast proliferation, making them suitable for bone tissue engineering applications. These findings provide valuable insights for developing new materials in bone tissue engineering and pave the way for future research in this field.

Smart polymer composites with vertically oriented boron nitride and carbon fiber for heat management: Magneto-thermal responsiveness

Emerging structural materials for aerospace deformable structures, soft robotics, and advanced smart electronic devices necessitate reversible, lockable, and reprogrammable shape transformation capabilities. A challenge in this realm is heat accumulation in high-power density devices, which limited impedes broader applications of these materials. This study introduces magneto-thermal coupling response and efficient heat dissipation to structural composite, facilitating reversible and reprogrammable material deformation. Our composites prepared using bi-directional freeze casting strategy demonstrated excellent thermal management capabilities. When the composites were applied to the chip heat dissipation, the chip temperature was significantly reduced by 36.3 °C from 112.2 °C. Furthermore, the integration of a flexible boron nitride nanosheets (BNNS)/carbon fibers (CFs) network with magnetic Fe3O4 particles and phase-change material enables effective magneto-thermal response. This magnetically controlled thermal deformation behavior of composites provides a promising avenue for the development of multimodal morphing structures for soft robotics and aerospace applications.

Corrosion Behavior of Nacre-Inspired (TiBw-TiB2)/Al Composites Fabricated by Freeze Casting.

Nacre-inspired metal matrix composites have received much attention due to their excellent deformation coordination ability, which can achieve the synergy of strength and ductility. The preparation of nacre-like Al matrix composites by freeze casting has been a promising application, but the continuous ceramic-rich layer affects the corrosion resistance of the composites, facing complex corrosion problems during service. In this work, the microstructure and corrosion behavior of the nacre-inspired (TiBw-TiB2)/Al composites fabricated by freeze casting and squeeze casting were systematically studied. The results indicated that the Al layers and ceramic-rich layers had little change, about 35 μm and 31 μm, respectively, with an increasing ratio of the Ti/TiB2. Meanwhile, a high Ti/TiB2 ratio resulted in an increase in the Fe-Ti intermetallic phases, which was detrimental to the corrosion performance of the composites and was prone to pitting. The electrochemical test results showed that the 3Ti7TiB2 composite had the lowest corrosion current density (15.9 μA) and intergranular corrosion depth (231 μm), indicating that it had the best corrosion resistance, which can be attributable to its stable and dense passivation film. Two different corrosion phenomena during the intergranular corrosion test existed in the present nacre-inspired (TiBw-TiB2)/Al composites: intergranular corrosion in the Al matrix layer and pitting corrosion in the ceramic-rich layer. Among all the composites, the corrosion depth of the 3Ti7TiB2 composite was the smallest and significantly less than that of the 2024Al alloy. In addition, the continuous ceramic-rich layer acted as a corrosion channel during corrosion, significantly degrading the corrosion resistance of the nacre-like Al composites.

Solar-heated mono-domain-structured ferrimagnetic cellulosic sponge fabricated by using bidirectional freeze casting for energy-efficient liquid adsorption

Liquid adsorption has a wide range of industrial and environmental applications. In recent years, interest in liquid adsorption technology that leverages porous materials has surged, primarily driven by these materials’ substantial surface area and adjustable wettability. However, high tortuous structures of conventional porous materials impede the flow of liquids, limiting their applicability in situations requiring rapid liquid adsorption such as oil spill cleanups. This study proposed two strategies for rapid liquid adsorption. We introduced a polydimethylsiloxane (PDMS) wedge to control ice crystal growth by generating a dual temperature gradient. This led to a mono-domain lamellar structure composed of vertically aligned channels. Cubic iron oxide nanoparticles (CION) were also utilized to enhance solar heating, that enabled rapid adsorption, even of high-viscosity liquids, without an external power supply unit for heating sorbents. The application of a solar-heated ferrimagnetic cellulosic sponge with precisely controlled channels facilitates the rapid removal of high-viscosity oils, which have traditionally been challenging for large-scale oil spill cleanups in oceans.

Freeze-Casting of Alumina and Permeability Analysis Based on a 3D Microstructure Reconstructed Using Generative Adversarial Networks.

In this study, alumina ceramics with hierarchical pores were successfully fabricated using freeze casting. Experimental studies show that both the solid loading of the slurry and the thermal insulation layer at the interface of the slurry and cooling plate can influence the pore characteristics of cast samples. In order to examine the pore characteristics and evaluate the permeability of the freeze-cast samples fabricated under different conditions, a generative adversarial network (GAN) method was employed to reconstruct the three-dimensional (3D) microstructure from two-dimensional (2D) scanning electron microscopy (SEM) images of the samples. Furthermore, GAN 3D reconstruction was validated against X-ray tomography 3D reconstruction results. Based on the GAN reconstructed microstructures, the permeability and pore distribution of the various samples were analyzed. The sample cast with 35 wt.% solid loading shows an optimal permeability.

Role of solvent composition and sintering time on the porosity of α‐alumina monoliths produced by freeze casting

AbstractThe present study reports the investigation of the influence of naphthalene–camphor binary solvent and the densification process on the pore structure formation of α‐alumina monoliths using the freeze‐casting technique with a freezing temperature control mechanism. Freeze‐casting technique allowed a controlled production of monoliths with high porosity (65%–70%) and distinct pore morphologies based on the adjustment of solvent composition (hypoeutectic, eutectic, and hypereutectic) and sintering time. In general, the longer the sintering time, the greater the average pore diameter (8–10 µm), the larger the grain size (∼319–596 nm), the higher the material density (∼1450–1650 kg/m3), the lower the open porosity (∼60%–49%), the higher the closed porosity (5%–18%), and the greater the compressive strength of the monoliths (hypoeutectic: 23.56 MPa; eutectic: 4.81 MPa; hypereutectic: 23.49 MPa). The study also reveals that the solvent composition directly influenced the alignment of the pore structure, as the pores of the final monolith resemble frozen solvent crystals. Hydraulic tortuosity varied from 1.30 to 1.53 for selected samples. Finally, solvent composition and sintering time proved to be important parameters that should be considered in the manufacturing process of porous ceramic structures via freeze casting.

Ultralight Three-Layer Gradient-Structured MXene/ Reduced Graphene Oxide Composite Aerogels with Broadband Microwave Absorption and Dynamic Infrared Camouflage.

Infrared and radar detectors posed substantial challenges to weapon equipment and personnel due to their continuous surveillance and reconnaissance capabilities. Traditional single-band stealth devices are insufficient for dual-band detection in both infrared and microwave bands. To overcome this limitation, a gradient-structured MXene/reduced graphene oxide (rGO) composite aerogel (GMXrGA) is fabricated through a two-step bidirectional freeze casting process, followed by freeze-drying and thermal annealing. GMXrGAexhibits a distinct three-layered structure, with each layer playing a crucial role in microwave absorption. This deliberate design amplifies both the efficiency of microwave absorption and the material's effectiveness in dynamic infrared camouflage. GMXrGA displays an ultralow density of 5.2 mg∙cm-3 and demonstrates exceptional resistance to compression, enduring 200 cycles at a maximum strain of 80%. Moreover, it shows superior microwave absorption performance, with a minimum reflection loss (RLmin) of -60.1dB at a broad effective absorption bandwidth (EAB) of 14.1GHz (3.9-18.0GHz). Additionally, the aerogel exhibits low thermal conductivity (≈26 mW∙m-1∙K-1) and displays dynamic infrared camouflage capabilities within the temperature range of 50-120°C, achieving rapid concealment within 30 s. Consequently, they hold great potential for diverse applications, including intelligent buildings, wearable electronics, and weapon equipment.

Modulating charge separation of Ce–TiO2 aerogel supported on chitosan derived ordered porous carbonaceous frameworks for promoting CO2 photoreduction activity

Developing efficient photocatalysts with low cost, high performance, and high selectivity is essential and imperative for CO2 conversion and utilization, yet it remains a big challenge. Herein, a novel Ce-doped TiO2 aerogel with oxygen vacancy anchored on the oriented carbonaceous (Ce–TiO2@CS) is synthesized by the sol-gel technique, combined with the freeze casting, supercritical drying technique, and heat treatment processes. The Ce–TiO2@CS aerogel has a typical aerogel-like structure, with the Ce–TiO2 aerogel anchored on the oriented porous carbon, rendering a large BET-specific surface area of 124 m2/g, which leads to enhanced photocatalytic activity. The Ce-doping into the pristine TiO2 results in impurity levels within the band gap, which extends the light response range to the visible light region. In addition, the rapid combination of electrons and holes is prevented via the two-phase microstructures and rapid transfer rate of electrons within the oriented porous carbon. The yields of CH4 and CO are as high as 9.45 μmol h−1 g−1 and 42.26 μmol h−1 g−1, respectively, which are 28.6 and 2.46 times higher than those of pristine TiO2 aerogel under simulated solar spectrum conditions without any sacrificial agents or co-catalysts, The density functional theory (DFT) calculation shows that larger C–O bonds of CO2 molecule and more negative adsorption energy have occurred on the Ce–TiO2@CS aerogel, indicating that the CO2 activation has been enhanced, which greatly improves the CO2 photoreduction activity. This work may guide the designing of aerogel-based photocatalysts for CO2 photocatalytic reduction.

Nature-inspired wood-like TPU/CB aerogels for high performance flexible strain sensors

Strain sensors based on porous conductive polymers (CPCs) have garnered growing research interest for their potential applications in motion detection, healthcare, human–computer interaction, and artificial intelligence. However, the complexity of CPC processing makes it difficult to achieve the controlled design of microscopic porous structures, leading to simple and random porous structures, thus limiting their further use in the field of pressure sensing. This paper presents a strain sensor with a high-performance, wood-like structure composed of flexible conductive carbon black/plastic polyurethane foam (BWCT) using a bidirectional freeze casting process. The results show that, compared with conventional random freezing and unidirectional freezing, the bidirectional freeze casting process can effectively realize multiscale control of the composite structure, which results in a good laminar porous structure of the prepared BWCT. This parallel laminar structure not only contributes to the layered transfer of stresses but also avoids the local concentration of stresses. At the same time, it significantly increases the directional electrical conduction ability, which results in high sensing stability performance. In particular, the BWCT sensors had a wide detection range (80%), a lower limit of detection (0.2%), rapid response and relaxation times (200 ms), as well as exceptional durability (>2000 cycles). Furthermore, the BWCT was integrated into a wearable sensor to monitor various human motions, including arm bending, squatting, and walking, demonstrating reliable detection performance. Altogether, the BWCT sensors are promising in expanding the application but also offer guidance for designing high-performance wearable strain sensors.

Porous silicate cement membrane: Unraveling the effect of triethanolamine on ice crystal changing, pore structure, and performance

Triethanolamine (TEA) has been broadly used as the organic amine conditioning agent to modify the workability of cement-based materials. However, the effect of TEA on the structure and property of porous silicate cement membranes has not been reported. In this paper, TEA was applied to study its effect on parameters of porous silicate cement membranes based on the preparation method combining freeze casting and heat-dry curing, because it is easy to form complexes with cement particles. The effect and acting mechanism of TEA on porous silicate cement membranes were researched using a series of characterizations and molecular dynamics (MD) simulation. Results showed that TEA significantly improved the performance of porous silicate cement membranes. The addition of TEA changed the pore morphology of porous silicate cement membranes from lamellar structures to cellular structures, with mesoporous size distribution focusing on 2.5–4.5 nm at TEA doping ratio of 0.16 wt%. The oil-water separation performance could reach up to 99.6 %. Through comprehensive comparison, the porous silicate cement membrane with 1.0 wt% TEA showed better holistic preponderance of oil-water separation and permeation flux. Quantum chemistry calculation and MD simulation were used to briefly explain the influence of TEA on phase transformation. MD showed that adding TEA changed the morphology and structure of ice crystals. The percentage of the Ih structure significantly increased from 53 % to 86 % after adding TEA. This study might expand the application of TEA in other aspects and enlighten relevant workers in new experimental designs.

Developing Porous Fibrin Scaffolds with Tunable Anisotropic Features to Direct Myoblast Orientation.

Functional regeneration of anisotropically aligned tissues such as ligaments, microvascular networks, myocardium, or skeletal muscle requires a temporal and spatial series of biochemical and biophysical cues to direct cell functions that promote native tissue regeneration. When these cues are lost during traumatic injuries such as volumetric muscle loss (VML), scar formation occurs, limiting the regenerative capacity of the tissue. Currently, autologous tissue transfer is the gold standard for treating injuries such as VML but can result in adverse outcomes including graft failure, donor site morbidity, and excessive scarring. Tissue-engineered scaffolds composed of biomaterials, cells, or both have been investigated to promote functional tissue regeneration but are still limited by inadequate tissue ingrowth. These scaffolds should provide precisely tuned topographies and stiffnesses using proregenerative materials to encourage tissue-specific functions such as myoblast orientation, followed by aligned myotube formation and recovery of functional contraction. In this study, we describe the design and characterization of novel porous fibrin scaffolds with anisotropic microarchitectural features that recapitulate the native tissue microenvironment and offer a promising approach for regeneration of aligned tissues. We used directional freeze-casting with varied fibrin concentrations and freezing temperatures to produce scaffolds with tunable degrees of anisotropy and strut widths. Nanoindentation analyses showed that the moduli of our fibrin scaffolds varied as a function of fibrin concentration and were consistent with native skeletal muscle tissue. Quantitative morphometric analyses of myoblast cytoskeletons on scaffold microarchitectures demonstrated enhanced cell alignment as a function of microarchitectural morphology. The ability to precisely control the anisotropic features of fibrin scaffolds promises to provide a powerful tool for directing aligned tissue ingrowth and enhance functional regeneration of tissues such as skeletal muscle.

Composite polymer electrolyte with vertically aligned garnet scaffolds for quasi solid-state lithium batteries

Structure design is of great importance for composite solid electrolytes to meet the high requirements for lithium batteries today. Herein, a novel composite polymer electrolyte with vertically aligned fast ion pathways has been constructed through the in-situ UV-induced polymerization of poly (butyl acrylate) (PBA) based gel polymer electrolyte inside the honeycomb-structure Li6.5La3Zr1.5Ta0.5012 (LLZTO) scaffolds by freeze casting. The addition of LLZTO enhances the anion adsorption through the Lewis-acid sites of the La ions and reduces the Li+ complexation by participating in the interaction of CO⋯Li+. Therefore, the interface of PBA and LLZTO scaffold serves as a continuous Li+ transport pathway and the resulting composite solid electrolyte exhibits a high ionic conductivity (5.098×10−4 S cm−1), near single-ion conducting characteristic (a transference number of 0.8) and high electrochemical stability window (5.15 V). Based on the above superior performance, the composite electrolyte promotes uniform distribution of lithium ion concentration and electrolyte potential. Thus, quasi-solid-state LiFePO4/Li cells exhibit excellent cycling performance (capacity retention of 91.7 % after 300 cycles at 0.5 C).

The study of double-network carboxymethyl chitosan/sodium alginate based cryogels for rapid hemostasis in noncompressible hemorrhage

Developing an injectable hemostatic dressing with shape recovery and high blood absorption ratio for rapid hemostasis in noncompressible hemorrhage maintains a critical clinical challenge. Here, double-network cryogels based on carboxymethyl chitosan, sodium alginate, and methacrylated sodium alginate were prepared by covalent crosslinking and physical crosslinking, and named carboxymethyl chitosan/methacrylated sodium alginate (CM) cryogels. Covalent crosslinking was achieved by methacrylated sodium alginate in the freeze casting process, while physical crosslinking was realized by electrostatic interaction between the amino group of carboxymethyl chitosan and the carboxyl group of sodium alginate. CM cryogels exhibited large water swelling ratios (8167 ± 1062 %), fast blood absorption speed (2974 ± 669 % in 15 s), excellent compressive strength (over 160 kPa for CM100) and shape recovery performance. Compared with gauze and commercial gelatin sponge, better hemostatic capacities were demonstrated for CM cryogel with the minimum blood loss of 40.0 ± 8.9 mg and the lowest hemostasis time of 5.0 ± 2.0 s at hemostasis of rat liver. Made of natural polysaccharides with biocompatibility, hemocompatibility, and cytocompatibility, the CM cryogels exhibit shape recovery and high blood absorption rate, making them promising to be used as an injectable hemostatic dressing for rapid hemostasis in noncompressible hemorrhage.

Silver nanowire bridged graphene framework for encapsulating phase change materials with high thermal conductivity and solar-to-heat conversion ability

To construct a high-efficiency thermally conductive graphene nanoplate (GNP) framework, ball-milling technique and silver nanowires (AgNW) bridging strategy were employed to improve the compatibility of GNP and the interfacial thermal resistance (ITR) in GNP skeletons, respectively. By using unidirectionally freeze casting technique, long range ordered GNP frameworks containing a small amount of AgNW as “bridge” were obtained, which were used to encapsulation phase change material (PCM). As a result, the honeycomb-like micropores of the framework with strong capillary effect give PCM anti-leakage and shape stability. The vertically aligned and AgNW bridged GNP skeletons form high-speed heat transfer paths endowith low ITR, thus significantly improve thermal conductivity to 7.24 W/mK. More importantly, GNP framework with strong light absorption ability endows PCM with well solar-to-heat conversion and storage ability. Therefore, AgNW bridged GNP framework endowing PCM with comprehensive thermal management ability exhibits a high potential in addressing the thermal problems of electronics.

Optimizing polymer composite dielectric properties via digital light processing 3D printing of ordered barium titanate skeleton

Through construction of a three-dimensional continuous ceramic network, the dielectric performance of polymer composites can be enhanced with a reduced amount of ceramic loading. However, the commonly employed methods, such as freeze casting or sacrificial template, fail to precisely control the structure of the ceramic skeleton, leading to significant randomness in content control. In this work, a Digital Light Processing (DLP) 3D printing technique is utilized to precisely fabricate ordered three-dimensional ceramic structures, which are further sintered at high temperatures to obtain a continuous barium titanate (BT) skeleton (BTS). This is then compounded with cyanate ester based polymers (CP) to prepare BTS/CP composites. Results show that when the content of BT is 61.2 vol%, the dielectric constant of the composite is 657 at 100 Hz, which is about 173 times higher than CP, while maintaining a lower dielectric loss of 0.026. Interestingly, the distribution of BTS in the composites has a significant impact on the dielectric performance of the composite. When the BT content is about 50 vol%, the dielectric constant of the “fine and dense” skeleton composite is 2.1 times higher than that of the “coarse and sparse” skeleton composite. This study proposes a novel strategy for building a structurally and compositionally controllable three-dimensional barium titanate (BT) network within polymers, demonstrating the noteworthy influence of macrostructure on the dielectric performance of polymer composites. This offers a fresh approach to the mass application of ordered three-dimensional ceramic skeleton enhanced polymer composites in the fields of electronics and electricity.

Superelastic bamboo fiber-based spongy aerogel for flexible piezoresistive sensors with wide response range and high sensitivity

Superelastic, breathable, and flexible piezoresistive sensors with excellent sensing performance are drawing tremendous attention in wearable electronics and sleeping furnishings. However, simultaneous realization of their high performance is still a huge challenge. In this study, inspired by the pore structure of natural sponges, a high-performance sponge-like bamboo fiber/graphene oxide aerogel piezoresistive sensor (M−CBF−rGO) was prepared utilizing bamboo fibers (BFs) and graphene oxide (GO) as raw materials through freeze casting and carbonization. Benefiting from the unique porous structure with effective absorbing/releasing energy, the M−CBF−rGO aerogel sensor exhibits excellent superelasticity (not being destroyed under 90 % deformation), mechanical durability (7,000 cycles), and good breathability. Moreover, the M−CBF−rGO sensor demonstrates ultra-high strain sensitivity (892.9), a wide detection range (0–300 kPa), and a fast recovery time (20 ms). Taking advantage of these benefits, the M−CBF−rGO sensor can not only be applied to detect human signals ranging from finger motion to swallowing recognition, but also integrated into the cushioning materials of upholstered furniture to generate a sensing array for monitoring and recogniting human activity including sitting postures and sleeping positions in real-time. This sensor demonstrates the potential application prospects in the fields of human health diagnosis, smart wearable products, and intelligent upholstered furniture.

High porosity hafnia ceramics by freeze casting

Highly porous hafnia ceramics are prepared by freeze casting. The major challenge resides in the high density of the hafnia particles typically leading to settling in the slurry. To address this, we optimized the suspension formulation to achieve structures with porosities of 68–74 %. Our approach includes a reduction in additive quantities and an adjustment of the pH value for suspension stabilization and prevention of particle settling. The use of PVA and PEG ensures a green body strength during the process yielding in cellular microstructure with pore channels aligned in the freezing direction throughout the sample. With increasing solid loading, the scaffolds become denser and the pore wall thickness increases. Compressive strength tests confirm the enhanced stiffness of the samples with 15 vol% hafnia. Samples with 10 vol% hafnia show a buckling-dominated failure behavior. Our results provide valuable insights to the preparation of suspensions containing high density materials.