High Temperature Thermal Shock Research Articles

Experimental and modeling investigation of the thermal shock behavior of TiC-based self-healing coatings on AISI 321 stainless steel

The AISI 321 steels of structural components serviced at high temperature are usually subjected to oxidation and thermal shock damage during service. Therefore, to improve their high-temperature oxidation and thermal shock resistance, the self-healing coating consisting of Al2O3-13 %TiO2 layer, TiC layer and NiCrAlY layer was prepared for 321 steels in this work. The experimental and microstructural characterization results showed that the thermal shock resistance of such self-healing coating was remarkably improved as compared to the counterpart double-AT13 coating. This is because the volume increment resulting from the oxidation reaction between the TiC and oxygen decreased the porosity of the self-healing coating and retarded crack growth, which also led to the improved high-temperature oxidation resistance. Further, a thermal shock life model based on the crack growth model of Paris formula were developed. The modeling results not only agreed well with the experimental results but also indicated that thickening of thermal grown oxide (TGO) is the main cause of crack initiation and growth.

High-temperature oxidation and gas thermal shock studies of IC10 simulated specimens with thermal barrier coatings

PurposeThe purpose of this study is to investigate the effects of high-temperature oxidation tests and gas thermal shock tests on IC10 simulated components with thermal barrier coatings under different temperatures and oxidation times.Design/methodology/approachIn the high-temperature oxidation test, specimens were oxidized at three different temperatures of 850, 980, and 1,100 °C for durations of 10, 20, 50, 100, 200, and 300 h, respectively. In the gas thermal shock test, specimens were pre-oxidized for 10, 20, 50, and 100 h, followed by a high-temperature gas thermal shock test at 1,100 °C.FindingsIn the high-temperature oxidation tests, with increasing oxidation time, the oxidation layer thickened, and the air-film holes diameter decreased. The microstructure of the bond coat transitioned from strip-like to block-like, and internal cracks transformed from numerous and short to larger and deeper. Below the bond coat, a noticeable disappearance layer of strengthening phase appeared, with increasing thickness. The strengthening phase in the substrate transitioned from regular square shapes to circles as temperature increased. In gas thermal shock tests at 1,100 °C, the oxidation weight gain ratio increased with longer pre-oxidation times, whereas the erosion weight loss ratio gradually decreased.Originality/valueThe originality and significance of this study lie in its departure from the typical subjects of high-temperature oxidation and thermal shock tests. Unlike common research targets, this study focuses on IC10 simulative specimens with thermal barrier coatings and air-film holes. Furthermore, it investigates the effects of varying temperatures and oxidation durations.

Insights into pyrolysis product characteristics and carbon structure evolution of bituminous coal under high-temperature thermal shock

The current investigation aims to reveal the pyrolysis characteristics and particle microstructure evolution of bituminous coal under the high-temperature thermal shock. In the experimental temperatures, the purification of carbon matrix in the coal char is a successive process linear on temperature. In contrast, the graphitization process of carbon structure existed a transition temperature (1600 ℃). Specifically, the range of 1000–1500 ℃ is critical for the transformation of amorphous carbon to disordered graphite, but the growth of graphite microcrystals was minimally affected. While the range of 1600–1900 ℃ is critical for the formation of the graphite-like carbon structure. It is characterized by the release of defective structures such as oxygen-containing functional groups, and a significant increase in crystal size. Although beneficial for the subsequent study of carbon materials, the ordered graphite transformation led to the deactivation of char. The pyrolysis behavior study under thermal shock insight into the thermal behavior of coal char in high-temperature furnaces, as well as a new idea for the clean utilization of coal resources.

High-temperature selective reduction of NOx into N2 catalyzed by different ion-doped titania

The active titanium-based composite oxide carrier with strong thermal stability and surface acidity is the key to ensure the steady operation of high-temperature deNOx catalyst for gas-fired exhaust. In this paper, W6+, Zr4+, Mo6+, Al3+, Si4+, Cu2+, Co2+, Mn2+, Fe3+ doped titanium-based composite oxides were synthesized by sol–gel method. The effects of ion species, doping amount, calcination temperature on NH3-SCR deNOx efficiency and resistance to water vapor and SO2 poisoning were investigated. Results showed that the Cu2+, Co2+, Mn2+, Fe3+ doped titanium-based composite oxides calcined at 630 °C had negligible deNOx activity, while the doping of W6+, Zr4+, Mo6+, Al3+ and Si4+ improved the NH3-SCR activity and anti-water vapor and SO2 poisoning of titanium-based composite oxide. The deNOx efficiency of the best compatibility of the five ions doping was TiW0.1Ox-630 > TiMo0.12Ox-630 > TiAl0.11Ox-487 > TiZr0.06Ox-538 ≈ TiSi0.04Ox-582, which was consistent with the order of total acid amount. The order of resistance to water vapor and SO2 poisoning and resistance to high temperature thermal shock was TiW0.1Ox-630 ≈ TiMo0.12Ox-630 > TiSi0.04Ox-582 > TiZr0.06Ox-538 > TiAl0.11Ox-487. Doping of five ions inhibited the transformation of anatase TiO2 to rutile TiO2 in different degrees. Among them, W6+ doping had the best inhibitory effect and the exposure ratio of TiO2 (101) crystal plane in TiW0.1Ox-630 was the highest, which was beneficial to NH3-SCR of NOx. Furthermore, the concentration of chemisorbed oxygen Oα was in the order of TiW0.1Ox-630 > TiMo0.12Ox-630 > TiAl0.11Ox-487 > TiZr0.06Ox-538 > TiSi0.04Ox-582. The higher the concentration of Oα is, the more conducive to the oxidation of NO to NO2 and the promotion of NH3 adsorption and dehydrogenation oxidation.

Mechanisms and experimental study of directional thermal shock fracture of granite under bidirectional horizontal loading

The study of the mechanism of thermal shock directional fracture of rocks under bidirectional horizontal stress is important for the application of directional thermal shock fracture technology. With the engineering background of the thick igneous roof overlying the coal seam, we conducted high temperature thermal shock directional fracture tests on granite under different horizontal loads to investigate the fracture mechanism. The results show that during the directional thermal shock of granite, the heating rate of borehole surrounding rock experienced three stages of rapid increase, rapid decrease and slowly decrease. AE tests were used to characterize the typical features of rocks during thermal shock fracture: the appearance of macrocracks in the specimen was accompanied by sharp increases in the cumulative AE count and the sudden drops in b-value. The experimental results show that thermal shock can create macroscopic directional fractures within the rock. Within a certain range of horizontal stress difference, the expansion direction of thermal shock cracks could be released locally from geological stress control, i.e. expanding along the direction of the minimum horizontal dominant stress. This provides completely new thinking for the cutting of hard roof and the directional fracturing of rock. In addition, directional thermal shock caused modifications in the distribution of stress in borehole surrounding rocks. We have established a model for stress distribution around the borehole rock and given the calculation formula for the initiation stress of the rock. The studies provide significant theoretical guidance for the industrial application of directional thermal shock fracturing technology.

Heat transfer mechanism and performance optimization scheme of refractory oxide solid heat storage materials

Clean energy advances can drive solid heat storage technology. Because of their high-temperature, corrosion, and excellent thermal shock resistance properties, refractory oxides are widely used as solid heat storage materials. However, their applications are limited owing to their poor heat-transfer performance resulting from their multicomponent, multiphase, and complex nature and thus understanding their heat-transfer mechanism will be crucial for their performance optimization. In this study, the thermal properties and mechanisms of corundum, high-alumina, and magnesia bricks were characterized using heat-transfer theories and models. Macroscopic analysis of the bricks revealed that they are all “internal porosity” materials. By comparing the weighting parameter j, the multiphase high-alumina brick shows poor heat-transfer path patency and the measured thermal conductivity is the lowest at 3.55 W m−1 K−1. Microscopic analysis found that in contrast to the thermal conductivity of other materials, the thermal conductivity of high-alumina bricks was significantly affected by phonon intrinsic scattering. Moreover, corundum and magnesia bricks exhibited a wider range of ultimate heat-transfer performance than the high-alumina brick. Hence, the heat-transfer performance of refractory oxide can be enhanced by increasing their particle contact, reducing the negative effects of microcracks, phases, and impurities, and by reducing the number of defects on phonon heat transfer, thereby providing an optimization scheme for improving the heat-transfer performance of the materials.

Oxidation behavior and thermal-shock resistance of AO20/Si3N4 coating for carbon/carbon composites

A new Si3N4 coating was proposed and prepared as bonding layer for improving the high temperature thermal shock resistance of carbon/carbon composites (C/C). It is found that the mass loss of the AO20/Si3N4 coating was 0.60% after oxidation at 1723 K for 69 h in air, and 2.86% after oxidation at 1673 K for 134 h. In particular, the coating sample has excellent thermal shock resistance, where the mass loss of the sample is only 0.03% after 33 times of thermal shock from 1673 K to room temperature. The excellent oxidation and thermal shock resistance are mainly attributed to the better thermal expansion mismatch of the coatings, self-healing ability of the glass layer, and the formation of Si2N2O, which expected to enhance the potential application of C/C in more severe thermal shock environment.

Frank Partial Dislocations in Coplanar Ir/C Ultrathin Nanosheets Boost Hydrogen Evolution Reaction.

Developing highly active and stable acidic hydrogen evolution catalysts is of great significance and challenge for the long-term operation of commercial proton exchange membrane (PEM) electrolyzers. In this work, coplanar ultrathin nanosheets composed of rich-Frank partial dislocations (FPDs) are first synthesized. Ir nanoparticles and carbon (Dr-Ir/C NSs) use a nonequilibrium high-temperature thermal shock method (>1200 °C) and KBr template-assisted techniques. Dr-Ir/C NSs exhibit excellent hydrogen evolution reaction (HER) performance with a remarkably high mass activity of 6.64 A mg-1 at 50 mV, which is among the best Ir-based catalysts.In addition, Dr-Ir/C NSs are able to operate stably at 1.0 A cm-2 for 200 h as a cathode in a PEM electrolyser, and the original coplanar ultrathin nanosheets structure are maintained after the test, demonstrating excellent stability against stacking and agglomeration. Geometrical phase analysis and theoretical calculations show that the FPDs produce a 4% compressive strain in the Dr-Ir/C NSs, and the compressive strain weaken the adsorption of H* by Ir, thus increasing the intrinsic activity of the catalyst.

The millisecond fabrication of medium-entropy alloy as a high-performance bifunctional electrocatalyst for ultralong-term rechargeable zinc–air batteries

Zinc air battery (ZAB) has widely recognized advantages such as high theoretical energy density, environmental friendliness, and safety. However, its cathodic reactions involve sluggish four-electron process oxygen reduction and oxygen evolution reactions (ORR and OER). Therefore, developing a cheap, efficient and durable dual functional oxygen electrocatalyst has important scientific significance and practical value for the development of ZAB. Herein, we applied noble metal free medium-entropy alloy (CoFeNi) nanoparticles which were in embedded nitrogen doped carbon framework (N-PCF) as a highly active and ultra-stable bifunctional electrocatalyst. The CoFeNi@N-PCF was prepared by high temperature thermal shock approach from ion-exchanged ZIF percussor to ensure the uniform dispersion of medium-entropy alloy, hierarchical porosity and strong metal-support interaction. Due to the medium-entropy induced synergistic effects, the as-prepared bifunctional electrocatalyst has a large ORR onset potential (Eonset) of 0.92 V and half-wave potential (E1/2) of 0.85 V (vs. RHE) in 0.1 M KOH. And the overpotential of OER in 1.0 M KOH is only 320 mV at 10 mA cm−2. When used in ZAB, the as-assembled rechargeable ZAB with the self-supported air electrode provides an extremely high-power density of 203 mW cm−2, a superior specific capacity of 812 mAh g−1, and amazing cycled steadily for 600 h. The assembled flexible ZAB with CoFeNi@N-PCF exhibits an excellent stability (over 45 h) and the excellent bending ability under different angles. This work can provide some new insights into the design and preparation of advanced bifunctional oxygen electrocatalysts for next-generation metal-air batteries.

Perovskite evolution on La modified Mn1.5Co1.5O4 spinel through thermal ageing with enhanced oxidation activity: Is sintering always an issue?

Non-precious metal oxides have great potential in catalytic deep oxidation of emitted hydrocarbons to help address various environmental pollution concerns. However, sintering issue is a stumbling block in practical application upon long-term high-temperature operation or thermal shock experience. Herein, La was applied to modify Mn1.5Co1.5O4 spinel to get a highly active oxidation catalyst with exceptional stability against high-temperature thermal ageing treatment. With thermal ageing at 750 °C for 100 h, the La modified Mn–Co composite reached 90 % conversion in toluene oxidation at 265 °C under the high WHSV of 120,000 mL g−1 h−1, while this value increased to 312 °C over blank Mn–Co spinel. The addition of La not only inhibited the growth of spinel nanocrystals, but also brought about perovskite formation through sintering, generating perovskite-spinel interfaces, thus enhancing both activity and stability. Meanwhile, the La modified Mn–Co spinel exhibited superior performance in presence of water or sulfur dioxide after thermal ageing treatment. This work offers a versatile strategy to design anti-sintering and active oxidation nanocatalysts based on non-precious metal oxides for industrial applications.

High-specific capacity thermal battery cathode Fe and Ni doped CoS2 by enhanced thermal stability and conductivity

CoS2 can meet the strict requirements of high probability output capacity and high energy output capacity of thermal batteries in modern weaponry thanks to its advantages of low resistivity and high thermal decomposition temperature combined with a full Li+ conductive electrolyte. Nevertheless, CoS2 has the limitations of a low voltage platform and theorical capacity. In this case, Fe and Ni are doped into the CoS2 lattice through low-temperature solid-phase sintering to synthesize Fe0.1Co0.8Ni0.1S2 with a single-phase structure. Fe0.1Co0.8Ni0.1S2 generated by the solid phase method has higher thermal stability, which can reduce the high temperature thermal shock at the immediate start of the thermal battery and assure the safety of the thermal battery in operation. Meanwhile, the mass loss of Fe0.1Co0.8Ni0.1S2 at 615 °C is only 5 %, allowing it to discharge at the maximum effective mass at the normal operating temperature(∼500 °C). Because of the synergistic action of Fe2+, Ni2+, and Co2+ in the discharge process, the discharge voltage of CoS2 increases significantly, giving CoS2 higher specific energy. The simultaneous boost in specific energy and specific capacity indicates that doping has been highly successful in modifying CoS2, making CoS2 more appropriate for the use of high current and long-life thermal cell systems.

Effect of High-Temperature Thermal Shock on Solar Absorption Rate of Alumina Coating

With the development of the aerospace industry, the close exploration of the Sun has become a human demand. However, close-range exploration means that the detection satellite needs to accept the test of high temperatures above 1400 °C, so a thermal protective coating is a necessary part of the detection satellite to isolate heat and reflected light. Al2O3 coating has the characteristics of high emissivity and low absorptivity, and it is the best choice for thermal protection coating. However, the coating is subjected to thermal cycles, including heating and cooling, as the satellite rotates around the Sun, which could result in a change in the structure and properties of the coating. Therefore, thermal shock experiments were carried out, and the influence of microstructure on the absorption rate of the Al2O3 coating was investigated. In this study, an Al2O3 coating was prepared by atmospheric plasma spraying (APS). The coating was subjected to a thermal shock (TS) test at 1400 °C using a self-made flame shock device, and coating samples under different thermal shock degrees were obtained. A scanning electron microscope (SEM) was used to characterize the coating pores, and the effects of the coating pore size, aspect ratio (A/R) and cracks in the coating on the optical properties of the coating under different thermal shock degrees were analyzed. In order to clarify the influence of coating microstructure changes on the optical properties of the coating under different thermal shock degrees, not only relevant experiments were carried out, but also the solar reflectivity of Al2O3 coatings with different pore structures was analyzed by the finite element method using finite-difference time-domain (FDTD). The results show that increasing the porosity and aspect ratio of the pores can improve the partial solar absorption of the coating. It was also found that the transverse crack propagation improves the solar reflectance of the coating.

A novel route to enhance high-temperature mechanical property and thermal shock resistance of low-carbon MgO–C bricks by introducing ZrSiO4

A novel route to enhance high-temperature mechanical property and thermal shock resistance of low-carbon MgO–C bricks by introducing ZrSiO4

Improving the anti-thermal-shock properties of Sc2O3-Y2O3-ZrO2-CaF2-PHB abradable coatings by fabricating the textures on ceramic matrix composites: experiment verification and numerical analysis

The abradable coating is one of the most important coatings for improving the efficiency of aeroengine. To improve the durability of Sc2O3-Y2O3-ZrO2-CaF2-PHB abradable coating under the conditions of high temperature thermal shock, the femtosecond laser processing technology is proposed to fabricate the texture on the surface of SiCf/SiC composites to improve the coating/matrix contact area. The environmental barrier coating (EBC) was prepared by vacuum plasma spraying (VPS) equipment on SiCf/SiC ceramic matrix composites to avoid water-oxygen corrosion. And the abradable coating was prepared by air plasma spraying (APS) equipment on the EBC. The thermal shock test of the abradable coating at (1,250 ± 50)°C was established in the simulated gas environment of the oxygen-propane flame, and the variation of interface stress between the layers during the thermal shock test was analyzed by ANSYS software. The hidden crack between the layers was detected by an infrared thermal imager. The results show that the surface textures have significant influences on the anti-thermal-shock properties of Sc2O3-Y2O3-ZrO2-CaF2-PHB abradable coating by improving the contact area and optimizing the interface stress distribution. The bonding strengths of the coating are increased by 14.6% and 42.2% when the surface textures increase the contact area of the substrate and the coating by 41.3% and 104%, respectively. Compared with the coatings without texture treatments, the coatings with texture treatments can reduce coating thickness by 30% and the coatings do not peel off after the thermal shock tests. Influenced by the cyclic thermal stress, the cracks of abradable coating are initiated at the defect position and gradually propagated a shell-like shape. The textures on the surface of SiCf/SiC composites have deep influences on improving the high-temperature thermal shock life of Sc2O3-Y2O3-ZrO2-CaF2-PHB abradable coating.

A Study on Long-Term Oxidation and Thermal Shock Performance of Nanostructured YSZ/NiCrAlY TBC with a Less Dense Bond Coat.

This paper focused on studying the performance of a nanostructured thermal barrier coating (TBC) system deposited by APS, which had a bond coat with inter-lamellar porosities that resulted during the manufacturing process. The higher porosity level of the bond coat was studied as a possible way to keep the thickness of the TGO under control, as it is distributed on a higher surface, thereby reducing the chance of top-coat (TC) spallation during long-term oxidation and high-temperature thermal shock. The TBC system consisted of nanostructured yttria partially stabilized zirconia (YSZ) as a top coat and a conventional NiCrAlY bond coat. Inter-lamellar porosities ensured the development of a TGO distributed on a higher surface without affecting the overall coating performance. Based on long-term isothermal oxidation tests performed at 1150 °C, the inter-lamellar pores do not affect the high resistance of nanostructured TBCs in case of long-term iso-thermal oxidation at 1150 °C. The ceramic layer withstands the high-temperature exposure for 800 h of maintaining without showing major exfoliation. Fine cracks were discovered in the ceramic coating after 400 h of isothermal oxidation, and larger cracks were found after 800 h of exposure. An increase in both ceramic and bond-coat compaction was observed after prolonged high-temperature exposure, and this was sustained by the higher adhesion strength. Moreover, in extreme conditions, under high-temperature thermal shock cycles, the TBC withstands for 1242 cycles at 1200 °C and 555 cycles at 1250 °C.

The microstructure evolution and failure mechanism of Sn37Pb solder joints under the coupling effects of extreme temperature variation and electromigration

The effect of electromigration and thermal shock on the microstructure evolution and failure mechanism in the Sn37Pb/Cu solder joints were investigated in this study. With increasing thermal shock cycles, Pb atoms acted as the dominant effective charge carrier, which migrated with the electron flow and accumulated at the anode side. As the number of thermal shocks extended to 20 cycles, the dissolution of Cu trace was found at the corner positions where the current was crowded in the solder joints. High and low temperature thermal shock demonstrated the acceleration of solder failure that accompanies an increase in peak temperature and shock frequency during electromigration process. Combining the extreme temperature thermal shock (–196 to 120 °C) with the current density of 2.0 × 104 A/cm2, the cracks were prone to initiate at the corner and then propagate along the IMC layers with thermal shock cycles. The high thermal stress caused by the thermal expansion mismatch between Sn37Pb solder and Cu pad with the large temperature variation (ΔT = 316 °C) significantly aggravated the crack propagation, which induced the failure of Sn37Pb solder joints after 22 cycles.

Thermal shock resistance of Cr/CrN/Cr/CrAlN multilayer anti-erosion coating

In this work, a 12 μm Cr/CrN/Cr/CrAlN erosion-resistant multilayer coating was prepared by arc ion plating. According to the application conditions of high-temperature changing environment, the high-temperature thermal shock performance and erosion resistance of the coating were studied. The results show that the Cr/CrN/Cr/CrAlN coatings show no change after thermal shock up to 700 °C. After thermal shock at 900 °C, the surface shows discolouration and wrinkling, and the nitride phase in the coatings disappears and Cr2O3 and α-Al2O3 phases appear. The hardness of the coating after thermal shock is reduced from 3658.57 Hv to 1930.96 Hv, and the adhesion strength is reduced from HF1 to HF4. The erosion rates of the coatings after thermal shock at room temperature, 300 °C, 500 °C and 700 °C do not vary significantly, and are within 1 mg/g at 30° and 90°. The coating is completely unprotective when the thermal shock temperature reaches 900 °C, reaching 2.731 mg/g at 30° and 4.832 mg/g at 90°. It shows that the coating has an anti-erosion protection effect within 700 °C, but the coating has completely failed after a thermal shock at 900 °C and has no protective effect.

Experimental study on acoustic emission characteristics of high temperature thermal shock directional fracturing of granite with different heating conditions

High temperature thermal shock directional fracturing of hard rock has tremendous promise in the mining and tunneling industries, but the utilization mechanism is unclear and must be resolved before taking it to the field application stage. In this study, the granite specimens were subjected to bidirectional horizontal loads using the real triaxial pressure testing machine, and the thermal shock fracturing tests were conducted utilizing the homemade thermal shock system. The AE (acoustic emission) system tracked the whole granite fracture process throughout the test in real time. The results showed that the granite‘s fracture time under the high temperature thermal shock was negatively related to the peak heating temperature and heating rate. The spectral analysis of the AE was employed to consider a large number of 20–40 kHz AE signals as a sign of thermal shock damage. By spatial localization of AE events, it was determined that the thermal shock cracks sprouted at the borehole edge in the specimen’s center. In the horizontal direction, the cracks extended from the center to the specimen edge; in the vertical direction, the cracks extended from the specimen surface to the deeper portion of the specimen. The RA-AF value analysis indicated that the granite thermal shock damage mode was a mixed tensile-shear damage mode dominated by tensile damage. In addition, the higher the heating rate, the higher the percentage of tensile cracks. Increasing the heating temperature promoted the formation of shear damage inside the specimen when the heating rate was equal. Analyzing the b-value and βt-value indicated that at low heating rates (10 and 60 °C/min), many micro-cracks formed inside the granite before merging into macro-cracks. However, with the higher heating rate (110 °C/min), the formation of micro-cracks and the macro-cracks within the granite proceeded almost simultaneously. The research results provided some experimental foundation and theoretical guidance for high temperature thermal shock directional fracturing of hard rocks.

The high temperature oxidation and thermal shock behavior of a dense WSi2–TaSi2 coating on Ta substrate prepared by a novel two-step process

In order to improve the oxidation resistance of the Ta substrate, a novel two-step process including molten salt electrodeposition (Na2WO4-WO3 system) and halide activated pack cementation was adopted to prepare a WSi2–TaSi2 coating on tantalum substrate. During the electrodeposition process, dense tungsten coatings were fabricated at current densities of 30 mA/cm2, 40 mA/cm2 and 50 mA/cm2. It was observed that the grain size exhibited a log-normal distribution. When the current density was 40 mA/cm2, the grain size and flattest surface of the tungsten coating reached 9.50 ± 0.23 μm and 6.792 μm, respectively. When performing the static oxidation test, the WSi2–TaSi2 coating could effectively protect the Ta substrate oxidized at 1600 °C for 30 h. This is attributed to the presence of dense SiO2 and Ta2O5, which acted as a protective layer and suppressed the further penetration of oxygen. Furthermore, due to the matching thermal expansion coefficient between each layer and the sealing ability of semi-molten SiO2, the four-layer SiO2–W5Si3–WSi2–Ta5Si3 coating could successfully pass 721 thermal shock tests from 1600 °C to room temperature.

Ratio-Tuning of Silica Aerogel Co-Hydrolyzed Precursors Enables Broadband, Angle-Independent, Deformation-Tolerant, Achieving 99.7% Reflectivity.

The super-white body might be defined as its reflectivity exceeding 98% at any angle in the visible light spectrum, which can be used in a variety of emerging fields including optics, energy, environment, aerospace, etc. However, elaborate synthesis of a light-weight, highly reflective super-white aerogel body remains a great challenge. In this work, fine-tuning of silica aerogel co-hydrolyzed precursor ratios, 99.7% reflectivity with angle-independence in the visible light spectrum has been successfully achieved when the areal density is only 0.129g cm-2 , which breaks through the theoretical bandwidth limit of photonic crystals as well as the measured reflectivity limit of conventional porous materials. Furthermore, the reflectivity of super-white silica aerogel remains unchanged after various harsh deformations including compression and bending 1000 times, solar (≈800W m-2 ), ultraviolet (≈0.68W m-2 ), and humidity (100%) aging for 100 days, liquid nitrogen (-196°C) and high-temperature (300°C) thermal shock 100 times. As proofs of performance, the resulting super-white silica aerogels have been used as the novel standard white plate for better spectrum calibration, as the flexible projector curtains for optical display, as well as the transmitted light reflective layer in the photovoltaic cell for improving the relative power conversion efficiency of 5.6%.