Thermal Shock Research Articles

Development of a novel Al-Si microcapsules with heat-resistant, high latent heat, and efficient solar heat absorption

Aluminum-silicon (Al-Si) alloys are prominent in high-temperature thermal storage due to their high thermal storage density, thermal conductivity, and low cost. Despite their potential, the corrosivity and chemical activity from their liquid phase leakage limit broader applications. The hydrothermal method, often used for encapsulating Al-Si into microencapsulated phase change materials (MEPCMs), consumes the core material, reducing latent heat values. Additionally, the inability to modify the shell material fails to meet multifunctional demands. Addressing solar thermal application needs, we developed a novel heat-resistant, high-latent-heat Al-Si MEPCMs using a “double-layer coating, sacrificial inner layer” approach. This method, originally proposed by our research group and first extended to the microencapsulation of high-temperature phase change materials (PCM), uses Al-12Si as the core, PMMA as the sacrificial layer, and SiO2 as the outer shell.The MEPCMs demonstrated an encapsulation efficiency of 90.7 % and a latent heat value of 454.9 J/g. By adjusting the core–shell ratio, the size of the internal void was optimized to enhance thermal performance and cyclic stability, with MEPCM-S3 maintaining 98.6 % of its latent heat (439.5 J/g) after 10 thermal shocks and 300 thermal cycles. Furthermore, surface loading of carbon black (CB) enhanced the spectral absorption rate to 87.72 % in the 200–2500 nm range, marking an 11 % increase. These modifiable, high-latent heat, and cycle-resistant Al-Si MEPCMs hold broad prospects for applications in high-temperature thermal storage and as next-generation efficient solar energy storage media.

Effect of Ti3AlC2 addition on the densification and high- temperature erosion resistance of TiB2 composite ceramics fabricated by SPS

TiB2-Ti3AlC2 composite ceramics were fabricated by spark plasma sintering (SPS) technique. The effects of Ti3AlC2 additive on the densification, mechanical properties and resistance to high-temperature aluminum liquid erosion of composite ceramics were investigated, and the mechanisms of densification and erosion resistance were highlighted, respectively. At sintering temperature of 1800 °C, pressure of 40 MPa, and holding time of 10 min, TiB2 composite ceramic with 40 wt% Ti3AlC2 acquired 98.9 % densification, 98.2 % thermal shock resistance, and 13.71 MPa∙m1/2 fracture toughness. The in-situ decomposition of Ti3AlC2 was clearly observed during the sintering process, and the generated liquid Al induced the liquid phase sintering mechanism, promoting the densification of composite ceramics. Besides, the simultaneous in-situ generation of TiC phase strengthened the TiB2 matrix and induced a mixed toughening mechanism of transgranular fracture and intergranular fracture, resulting in superior mechanical properties and better resistance to high-temperature erosion of TiB2-Ti3AlC2 composite ceramics.

Temperature-responsive self-healing coating with excellent resistances to oxidation and thermal shock from core-shell B2O3@SiO2 microcapsule

Hierarchical design was applied to core-shell B2O3@SiO2 microcapsule, followed by fabrication of the SiC–B2O3@SiO2 coating by a combination of entrapping and hot dip processes. Among the C/C-SiC-BS2, C/C-SiC-BS4 and C/C-SiC-BS6 samples, the C/C-SiC-BS4 composite exhibits long-term antioxidant capabilities, with only a 2.30 % mass loss as oxidized at 973 K for 1500 h, and 2.35 % at 1073 K for 2600 h. Furthermore, after enduring 150 thermal shocks between 293 K and 1173 K, its mass loss is only 2.07 %. The XRD patterns detected the existence of B2O3 and SiO2 phases, and the SEM and EDS analysis proved the borosilicate glass, indicating the excellent performances came from the synergistic self-healing effects of the B2O3, SiO2 phases, and borosilicate glass. Thus, within the temperature ranges from 873 K to 1273 K, the oxygen penetration shifts from osmotic state to defect diffusion in coating. This research emphasizes the significance of hierarchical designs for core-shell sacrificial phase in silicate coatings, thereby enhancing their long-term applicability.

Continuous Rapid Fabrication of Ceramic Fiber Sponge Aerogels with High Thermomechanical Properties via a Green and Low-Cost Electrospinning Technique.

Ceramic aerogel is an appealing fireproof and heat-insulation material, but synchronously improving its mechanical and thermal properties is a challenge. Moreover, the expensive discontinuous processing techniques inhibit the large-scale fabrication of ceramic aerogels. Here, we propose a water-based electrospinning method, based on the hydrolysis and condensation reactions of ceramic precursor salts themselves, for the continuous and rapid (0.025 m3/min) fabrication of ceramic fiber sponge aerogels with dual micronano fiber networks, which show synchronous enhanced fireproof, thermal insulation, and resilience performance. The elastic ceramic micro/nano fiber sponge aerogels contain robust silica-based microfibers as a firm skeleton and alumina-based nanofibers as elastic thermal insulation filler. The sponges have a high porosity of >99.8%, a low mass density (6.21 mg/cm3), a small thermal conductivity (0.022 W/m·K), and a large compression strength (21.15 kPa at 80% strain). The ceramic fiber sponges can effectively prevent the propagation of thermal runaway when a lithium battery experiences catastrophic thermal shock (>1000 °C) in the power battery packs. The proposed strategy is feasible for low-cost and rapid synthesizing ceramic aerogels toward effective battery thermal management.

Upcycling process of mill scale waste into high-value ceramic products

Ceramic industry consumes large amounts of raw materials, including costly and environmental impact iron based-pigments. Steel rolling (SR) and wire drawing (WD) waste, rich in iron (>67 wt %), present a viable alternative. This study aims to develop high value stoneware pastes for tableware products by substituting commercial pigments with SR and WD. The influence of incorporation content (3, 5 and 10 wt %) and pre-treatments (sieving at 250, 150 and 63 μm, and grinding followed by sieving at 63 μm) on the samples properties was assessed including weight loss, firing shrinkage, apparent density, flexural resistance, and water absorption. The laboratory scale results revealed that darker hues, ranging from grey to reddish, were obtained when SR and WD were incorporated in the stoneware paste (beige colour). The smaller the particle size, more homogeneous is the developed colour, which is intensified as higher is the incorporation level.The prototypes (plates) were characterized in terms of thermal shock, edge impact, cracking and microwaves resistance, water absorption, and leaching behaviour, demonstrating that they met the industrial requirements. Thermal shock resistance was enhanced and the levels of leached Fe, Pb, Cd, Ni, Cr, Mo, V, Zn, and Cu, were below permissible limits (EU Ceramic Directive 84/500/EEC, Decree-Law n°152/2017, Decree-Law n°236/98 and WHO Guidelines for Drinking-Water Quality) confirming their effective immobilization. Concluding, this work shows the viability of using mill scale waste as a valuable secondary raw material in stoneware pastes acting as a chromophore agent. Dark colours are obtained while preserving the product technical characteristics, promoting sustainable production and reducing landfilled waste.

A Strategy for Anode Recovery and Upgrading by In Situ Growth of Iron-Based Oxides on Microwave-Puffed Graphite.

Faced with the increasing volume of retired lithium-ion batteries (LIBs), recycling and reusing the spent graphite (SG) is of great significance for resource sustainability. Here, a facile method for transforming the SG into a carbon framework as well as loading Fe2O3 to form a composite anode with a sandwich structure is proposed. Taking advantage of the fact that the layer spacing of the spent graphite naturally expands, impurities and intercalants are eliminated through microwave thermal shock to produce microwave-puffed graphite (MPG) with a distinct three-dimensional structure. Based on the mechanism of microwave-induced gasification intercalation, a Fe2O3-MPG intercalation compound (Fe2O3-MPGIC) anode material was constructed by introducing iron precursors between the framework layers and subsequently converting them into Fe2O3 through annealing. The Fe2O3-MPGIC anode exhibits a high reversible capacity of 1000.6 mAh g-1 at 200 mA g-1 after 100 cycles and a good cycling stability of 504.4 mAh g-1 at 2000 mA g-1 after 500 cycles. This work can provide a reference for the feasible recycling of SG and development of high-performance anode materials for LIBs.

Ti4+ doped high-entropy fluorite oxide ceramics ((ZrHfCeYEr)(1-x)/5Tix)O2-δ: Thermal, mechanical and cyclic thermal shock resistance properties studies

High-entropy fluorite oxide ceramics are promising candidates for spacecraft applications due to their excellent high-temperature thermal-mechanical properties. In this work, four kinds of high-entropy fluorite oxide ceramics ((ZrHfCeYEr)(1-x)/5Tix)O2-δ (HEFOs, x = 0, 0.025, 0.05, 0.075) with different Ti4+ contents were successfully synthesized through solid-state reaction method with conventional sintering. They all exhibited phase stability when annealed at 1500 ℃ for 20 h. When the content of Ti4+ was increased to x = 0.075, the thermal conductivity reduced to1.34 W·m−1·K−1 at 1100 ℃, and the hardness and elastic modulus increased to 14.01 GPa and 205.70 GPa, respectively. Furthermore, the cyclic thermal shock resistance of HEFOs at different temperatures was investigated. The initial flexural strength reached 219.03 MPa when the content of Ti4+ was increased to x = 0.075. After 60 thermal shock cycles at 1200 ℃ and 1500 ℃, the residual strength ratios were 97.56 % and 83.36 %, respectively. The results of this study establish the foundation for future applications of high-entropy fluorite oxide ceramics in spacecraft hot-end components.

Influence of acute heat shock on antioxidant defense of tropical fish, Psalidodon bifasciatus

Psalidodon bifasciatus is a fish species sensitive to physical and chemical changes in water. It serves as a good bioindicator of temperature variations and is utilized in environmental monitoring studies in Brazilian rivers. The objective of this study was to evaluate antioxidant defense biomarkers in the heart, brain, and muscle of P. bifasciatus exposed to a 10 °C thermal increase. P. bifasciatus were collected and divided into a control group (21 °C) and groups subjected to thermal shock (31 °C) for periods of 2, 6, 12, 24, and 48h. Two-way ANOVA indicated that a 10 °C temperature increase caused oxidative stress in P. bifasciatus. This was evidenced by altered levels of lipid peroxidation (LPO), carbonylated proteins (PCO), and glutathione peroxidase (GPx) in the heart, catalase (CAT) and LPO in the brain, and LPO in the muscle. Principal component analysis (PCA) and integrated biomarker response (IBR) analysis indicated that, compared to the heart and muscle, the brain exhibited a greater activation of the antioxidant response. Sensitivity analysis indicated that the muscle was the most sensitive organ, followed by the brain and heart. Our results indicate that the stress response is tissue-specific through the activation of distinct mechanisms. These responses may be associated with the tissue's function as well as its energy demand. As expected, P. bifasciatus showed changes in response to thermal stress, with the brain showing the greatest alteration in antioxidant defenses and the muscle being the most sensitive tissue.

Low Current Density Cathode Plasma Electrolytic Deposition of Aluminum Alloy Based on a Bipolar Pulse Power Supply

The present paper reported a novel bipolar-pulse cathodic plasma electrolytic deposition (BP-CPED) technique with a low current density. This newly developed CPED technique can break down the barriers of the existing CPED technique with higher current density. In this report, ceramic coatings were successfully prepared on aluminum alloy via the BP-CPED technique in an aqueous carbamide-based electrolyte. Data recording results in the reacting process show that there is the current density of the cathode below 0.15 A/cm2 and that of the anode below 0.035 A/cm2, which approximately reaches the level of conventional MAO technique. Interestingly, the addition of PEG into the electrolyte can further reduce the current density and effectively improve the coating quality. The kinetic of the BP-CPED process was discussed based on the evolution of current density/voltage-time curves and spark discharge phenomena. SEM observations illustrate that BP-CPED coatings possess a typical porous-surface feature. XRD analysis indicates that the coating was mainly composed of Al2O3 and Al4C3. Al2O3/Al4C3/ZrO2 composite coatings fabricated after Zr-doping reflected the successful Zr-incorporation into the coating, which demonstrated that the BP-CPED technique can be used to design the coating composition by the doping modification. The direct pull-off and thermal shock tests confirmed that new BP-CPED coatings obtained under the cathodic plasma discharge have excellent bonding strength. It is possible that this novel BP-CPED technique can provide a promising choice in developing the large-area CPED surface treatment for the industrial application.

Impact damage resistance and tolerance of alumina-based oxide/oxide ceramic matrix composite upon one sided thermal shock and hold

In this study, ceramic matrix composite specimens constituting Nextel™720 fibers and alumina matrix were subjected to one-sided thermal shock and subsequent 30-min hold at temperatures of 1200℃, 1350℃ and 1500℃. The plates were then subjected to low velocity impact at 5 J impact energy, followed by edgewise compression with digital image correlation. No noticeable change in mass, roughness and specimen dimensions were observed after the thermal shock and hold event at any of the temperatures for any of the specimens. External and internal damage resulting from the impact event also showed no dependence on the thermal shock temperature. The percentage compressive strength retention after low velocity impact ranged from 61 % to 68 % for all cases considered, again with no trends observed based on shock temperature. However, the compressive modulus for the impacted panels that were exposed to high temperature were higher than the pristine (non-thermal shocked) impacted panels.

Impact fracturing of rock-like material using carbon dioxide under different temperatures and pressures

Unconventional resources (oil, gas, and geothermal) are often buried deep underground within dense rock strata and complex geological structures, making it increasingly difficult to create volumetric fractures through conventional hydraulic fracturing. This paper introduces a novel method of supercritical energetic fluid thermal shock fracturing. It pioneers a CO2 deflagration impact triaxial pneumatic fracturing experimental system, using high-strength similar materials to simulate deep, hard rock masses. The study investigates the rock-breaking process and crack propagation patterns under supercritical CO2 thermal shock, revealing and discussing the types of thermal shock-induced fractures, their formation conditions, and discrimination criteria. The research indicates that higher supercritical CO2 thermal shock pressures and faster pressure release rates facilitate the formation of radial branching fractures, circumferential cracks, and branch cracks. Typically, CO2 thermal shock generates 3–5 radial main cracks, which is significantly more than the single main crack formed by hydraulic fracturing. The formation of branched cracks is often caused by compression-shear failure and occurs under relatively harsh conditions, determined by the confining pressure, rock properties, peak thermal shock pressure, and the pressure sustained post-decompression. The findings are expected to offer a safe, efficient, and controllable shockwave method of supercritical fluid thermal shock fracturing for the exploitation of deep unconventional oil and gas resources.

Impact of cyclic thermal shocks on the electrochemical and tribological properties of Fe-based amorphous coating

Fe-based amorphous coatings hold immense potential for marine industries due to their remarkable properties, including high hardness, exceptional corrosion resistance, and outstanding wear resistance. However, their performance under thermal shock conditions, particularly in high-temperature applications, remains a topic requiring further investigation. In this work, a Fe-based amorphous coating with a composition of Fe48Mo14Cr15Y2C15B6 was successfully developed using High-velocity oxygen fuel thermal spraying. To assess the thermal shock resistance of the amorphous coating, we subjected them to thermal cycles at 300 °C for 150 times, followed by cooling in two different mediums: saltwater quenching and air cooling. The results revealed that the coating maintained excellent contact with the substrate and preserved mainly amorphous structure both in the as-sprayed condition and after thermal shocks. Interestingly, the differential scanning calorimetry (DSC) results indicated that the air-cooled samples exhibited greater structural relaxation and crystallization compared to the brine-quenched samples. This microstructure changes in the air-cooled samples resulted in inferior mechanical properties, such as wear resistance and hardness, compared to the brine-quenched and as-sprayed samples.

Thermal shock behavior of novel (Yb0.1Gd0.9)2Zr2O7 thermal barrier coatings with a Cr modified (Ni, Pt)Al bond coat

The durability of thermal barrier coatings (TBCs) is significantly influenced both by the ceramic top coat and the bond coat. In this study, novel YbGdZrO ceramic coats were deposited on the surfaces of three types of Cr-modified (Ni, Pt)Al bond coats via electron beam physical vapor deposition (EB-PVD) technique. These Cr-modified (Ni, Pt)Al bond coats were fabricated by magnetic sputtering Cr onto the (Ni, Pt)Al bond coats with varying sputtering times of 30, 60, and 90 min. The results indicates that the thickness of the Cr-modified layer increases with the extension of sputtering time. A short deposition time of 30 min is adequate for achieving an appropriate Cr content in the (Ni, Pt)Al bond coats, which ensures selective oxidation of Al element within the bond coat and further enhances the metallurgical interfacial bonding strength with the ceramic coat by adapting to the concentration gradient diffusion. However, as the sputtering time is extended to 60 and 90 min, α-Cr begins to form in the Cr-modified (Ni, Pt)Al bond coats, which negatively affects the oxidation resistance of the bond coat. Consequently, the thermal shock life of the TBCs samples is significantly reduced with increasing sputtering time. The longest thermal shock lifetime is obtained on the bond coat with Cr plating time of 30 min owing to a differing thermally grown oxide formation and failure mechanism.

Improved sinterability and thermal shock resistance of MgO–ZrO2 composites due to in-situ formed MgAl2O4

To solve the problems of high cost and high firing temperature of ZrO2 inserted rings of slide plates, the in-situ MgAl2O4 (MA) toughened MgO–ZrO2 new ring materials were prepared using lightly calcined MgO, m-ZrO2 and nanoscale Al2O3. The effects of MgO/ZrO2 ratio and the amount of nanoscale Al2O3 on properties of samples were investigated. The results showed that the sinterability and mechanical properties of MgO–ZrO2 composites improved significantly due to the MA formed in situ by reaction between MgO and Al2O3, which promoted reactive sintering and densification of the samples. The improved thermal shock resistance (TSR) in MA-toughened MgO–ZrO2 composites was attributed to microcracks developed due to thermal expansion mismatch, MA and ZrO2 also acted as bridging particles, improving the ability to prevent crack propagation of the composites. The optimum MgO/ZrO2 ratio and addition amount of nanoscale Al2O3 were 7/3 and 3 wt%, respectively.

Effects of SiC/ZrO2 ratio on the key service performance of BN-ZrO2-SiC composites

BN-ZrO2-SiC composites have excellent comprehensive performance, which can be used in iron and steel metallurgy, such as side dams for thin strip continuous casting. In this paper, the influence of SiC/ZrO2 ratio on the structure and properties for BN-ZrO2-SiC composites was investigated, and the atmosphere used for corrosion tests was more closely to the real usage situation. The results show that with the increase of SiC/ZrO2 ratio, the thermal shock resistance of BN-ZrO2-SiC composites increases, as well as the corrosion resistance by molten steel decrease. When the SiC/ZrO2 ratio is 35:15, the BN-ZrO2-SiC composites present the best comprehensive performance, and its hardness and modulus of elasticity are higher than those of other samples, which are 165.8 MPa and 101.9 GPa, respectively.

The study on interaction mechanisms between Ti48Al2Cr2Nb alloy and Y2O3 ceramic crucibles with good thermal shock resistance: Assessing a novel, cost-effective approach to the preparation of high-performance TiAl alloys

Enhancing the thermal shock resistance of Y2O3 ceramic crucibles, coupled with advancements in melting and casting technologies to reduce the adverse influence of interfacial reactions, is essential for producing low-energy consumption, high-quality titanium-aluminum (TiAl) alloys. In this study, the Y2O3 ceramic crucible with good thermal shock resistance was developed through the optimization of particle size distribution and sintering holding time. The interaction mechanisms between Y2O3 ceramics and TiAl alloys under extreme conditions were investigated, and strategies for enhancing the mechanical properties of TiAl alloys through the integration of Y2O3 crucibles with centrifugal casting were discussed. The results indicated that introducing large particles of 1–3 mm under sintering conditions of 2023 K and 6 h effectively enhances the thermal shock resistance of Y2O3 crucible. The interaction between Y2O3 and TiAl alloys primarily involved physical erosion (spalling/dispersion), dissolution of separated particles, and surface modification of interface layer particles (reaction). Physical erosion played an important role in this dynamic interaction, with the extent of erosion intensifying through continuous use of the crucible, while electromagnetic forces ensured the uniform distribution of inclusions within the TiAl alloy matrix. Moreover, the application of centrifugal casting technology substantially refines the grain size and reduces the inclusion count, thereby significantly enhancing the mechanical properties of TiAl alloy.

Oxidation and corrosion resistance of resin-bonded magnesia-based refractories reinforced by CaB6 addition for secondary refining

Excellent properties are required for refractories used for secondary refining because of the harsh service conditions. The current study investigated the effect of calcium boride (CaB6) on the properties of magnesium oxide (MgO)‒based refractories. The sample with 0.4 wt% CaB6 exhibited excellent properties. It possessed the highest bulk density indicating that a suitable content of CaB6 can increase the compactness of the refractories. The in-situ formation of aluminum oxycarbonitride (Al3CON) at high temperatures in the MgO-based refractories was from the reaction of Al, Al4C3, AlN, and Al2O3 due to the addition of Al powders, which endowed them with high strength. The refractory containing 0.4 wt% CaB6 also exhibited the highest hot modulus of rupture (HMOR) of 26.6 MPa, which was around 2.5 times the strength of commercial MgO‒CaO bricks and 1.5 times that of the samples without CaB6 addition. In addition, it exhibited the best oxidation resistance revealed by the minimum thickness of the decarbonization zone, because the addition of CaB6 promoted the formation of a dense magnesium aluminate spinel (MgAl2O4, MA) layer between the oxidized and non-decarburized zone in the refractories, thereby promoting the resistance of the samples to oxidation. It also exhibited excellent thermal shock resistance, and the residual strength ratio reached 76.6 %. The corrosion depth of the sample containing 0.4 wt% CaB6 was 9.8 % that of the MgO‒CaO bricks. This work indicates a potential alternative for producing high‒performance resin‒bonded MgO-based refractories with CaB6 in secondary refining furnaces.

Thermal shock resistance of silica gel‐modified magnesium carboxylate‐bonded high alumina castables

AbstractSilica gel‐modified hydratable magnesium carboxylate (HMC) is used as the binder for refractory castables. The mechanical strength and thermal shock resistance of HMC bonded and silica gel‐modified HMC‐bonded castables were compared. When the HMC/silica gel mass ratio is 2, the cold modulus of rupture, the hot modulus of rupture, the residual strength ratio after three‐times water quenching tests, and the matrix‐specific fracture energy of the castables were increased by 300%, 124%, 44.7%, and 132%, respectively, compared with HMC‐bonded castables. The characterization of microstructure evolution of silica gel‐modified HMC‐bonded castables indicated that a small amount of liquid phase generated is conducive to improving the high‐temperature mechanical properties. The in situ alumina‐rich spinel and needle‐like mullite toughened the matrix and enhanced the thermal shock resistance of the castables by “microcrack generation” and “preventing crack propagation” mechanisms.

Enhancing side die resistance to thermal shock in automotive casting: a comparative study of FCD550 and SKD6 materials

Enhancement of side die resistance to thermal shock in mold disc car applications was achieved by substituting FCD550 material with SKD6 material. The primary issue addressed is the cracking of side dies due to thermal shock induced by an accelerated production process, leading to production halts and failure to meet large customer orders. The study aims to identify a material that can better withstand thermal shock than FCD550, thereby improving the durability of side dies and the overall productivity of the manufacturing process. The research involved direct production experiments, analyzing the materials FCD550 and SKD6, evaluating die characteristics, and assessing finished product attributes before and after material changes. Laboratory tests and machine-setting trials were conducted, varying production processes and assessing the results. The findings indicate that SKD6 is significantly more resistant to thermal shock than FCD550 in mold disc car applications. The study compared the strength of side die materials using data sheets and adjusted setting parameters under existing cooling conditions. Experimentation involved altering the standard temperature from 520 °C–545 °C to 532 °C–538 °C and reducing the soaking time from a minimum of 270–540 seconds to 332 seconds. This reduced soaking time from 69 seconds to 46 seconds and aging time from 190 seconds to 180 seconds, increasing casting productivity from 194,870 pieces/28 days to 213,311 pieces/28 days across seven machines, thereby fulfilling the customer’s requirement of 200,000 pieces/28 days without side die cracks. Durability testing on five product samples according to TSD5605G standards confirmed the quality as meeting customer specifications

Effects of Alumina Bubble Addition on the Properties of Corundum-Spinel Castables Containing Cr2O3.

Purging plugs made of corundum-spinel castables containing Cr2O3 have been widely utilized in secondary refining process. However, their poor thermal shock resistance has greatly limited the improvement of their service life. Aiming to enhance their properties, we introduced alumina bubbles (ABs) to corundum-spinel castables, and the effects of the AB addition on the properties of the castables are studied in this manuscript. The results indicate that the apparent porosity, permanent linear change, cold strength, and hot strength all increased with an increasing AB amount. The thermal shock resistance of the samples with the AB addition was improved; the residual strength and residual strength ratio of the sample with 4 wt% ABs was the best. The effects of ABs on the tabular alumina aggregate distribution and relationship between the cold strength of the samples and the AB content was evaluated via the box dimension method. With the increments of AB content, the box dimension value of the tabular alumina within the samples significantly decreased, indicating that the tabular alumina aggregate distribution was related to the amount of ABs. In addition, the relationship between the box dimension and the strength was also established.