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Article

Effect of B4C Content on the Oxidation Resistance of a B4C-SiO2–Albite/Al2O3 Coating at 900 °C

by
Pengbin Chen
1,
Quanhao Luo
1,
Haoze Wang
1,
Huan He
1,2,3,
Tao Liu
1,2,3,
Yingheng Huang
1,2,3 and
Tianquan Liang
1,2,3,*
1
School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China
2
State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Guangxi University, Nanning 530004, China
3
MOE Key Laboratory of New Processing Technology for Nonferrous Metals and Materials, Guangxi University, Nanning 530004, China
*
Author to whom correspondence should be addressed.
Coatings 2025, 15(6), 688; https://doi.org/10.3390/coatings15060688
Submission received: 12 May 2025 / Revised: 31 May 2025 / Accepted: 3 June 2025 / Published: 6 June 2025
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Versions Notes

Abstract

:
B4C is beneficial for forming a glassy film that is effective at impeding oxygen diffusion and improving the oxidation resistance of coatings at high temperature. The effect of B4C content on the oxidation resistance of a B4C-SiO2–Albite/Al2O3 (BSA/AO) double-layer coating by the slurry brushing method at 900 °C was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), and differential scanning calorimetry (DSC) with thermogravimetric analysis (TGA) in this work. It is indicated that the composite coating with 20 wt% B4C exhibits excellent oxidation resistance at high temperature, which shows a mass loss of only 0.11% for the coated carbon block after being exposed to 900 °C for 196 h. This is attributed to the in situ formation of a thin, dense glass layer with good self-healing ability at the interface of the B4C-SiO2–Albite/Al2O3 composite coating within 1 h and the persistence and stability of the dense glass layer during exposure. The mechanism is discussed in detail.

1. Introduction

Anode carbon blocks are indispensable components of aluminum electrolysis due to their high electrical conductivity and electron-donating properties [1,2]. However, the carbon anode exhibits high oxidation susceptibility and suffers from severe oxidation when exposed above 400 °C [3], accelerating the consumption of carbon anodes and carbon emission during the electrolytic aluminum process [4]. The application of the Al2O3 ceramic coating to protect the anode carbon from oxidation is one of the possible strategies to prolong the service life [5,6,7,8], reduce the carbon emissions, and save costs for the electrolytic aluminum process [9,10]. However, the intensive use of the single, pure Al2O3 ceramic coating is limited due to the insufficient anti-oxidant performance [11,12]. More work has been performed to develop a novel coating material to enhance the thermal stability, acid–alkali resistance, and long-term durability of the coating under the conditions of aluminum electrolysis processing [13,14,15].
It is reported that the borosilicate glassy coating exhibits excellent oxidation resistance and self-healing capability at 700–1200 °C owing to the incorporation of B4C as a key constituent [16,17,18,19,20]. B4C is oxidized and forms B2O3 during exposure at high temperature, and then B2O3 reacts with SiO2 to form borosilicate glass. The glassy film is believed to be a prospective coating against oxidation due to the excellent resistance to O diffusion, good self-healing property, and the low melting point and suitable viscosity. Deng et al. [21] revealed that the PSN/borosilicate glass–B4C coating with the addition of 25 wt% B4C via the slurry brushing method showed excellent self-healing property and oxidation resistance due to the formation of a borosilicate glass-based coating at high temperature. The Al2O3-C refractory covered with SiO2-B4C–glass coating had a weight loss of only 1.721% after 100 h duration at 800 °C, showing good oxidation resistance [22]. Paper [23] reports that the application of the HfB2-SiC ceramic coating at medium-to-low temperatures can be broadened by B4C modification. Nevertheless, the long-term stability of the glassy coating at high temperature is challenged due to the progressive oxidation and volatilization of the boron element from the coating when increasing exposure temperature and time [24,25].
Many studies have been performed to improve the long-termed oxidation resistance property of the borosilicate glass coating through incorporating appropriate Al2O3 [26,27,28,29]. Appropriate addition of Al2O3 could promote the formation of strong -B-O-Al- bonds in the SiC/B4C-B2O3-SiO2-Al2O3 composite coating, which become a solid skeleton to stabilize the glass phase and reduce the loss of the B component over a long period [30]. The modification by Zr addition could increase the viscosity of borosilicate glass, improving the integrality and the oxidation resistance of the coating due to the formation of high-melting-point reaction products with Zr such as ZrSiO4 [31]. Another feasible strategy is that a multi-layered coating of the matrix SiC-HfB2/SiC could effectively protect the C/C composites from oxidation for 597 h at 1573 K and 382 h at 1773 K, indicating that an outer layer could mitigate the oxidation and volatilization of the effective element in the inner layer [32].
The content of B4C in the coating is one of the key factors in the long-term oxidation resistance property. Aiming to reveal the effect of B4C concentration on the performance against oxidation after long exposure at 900 °C for the double-layered B4C-SiO2–Albite/Al2O3 (BSA/AO) coating, the phase constitution, microstructure, and reactions between the components in the composite coating were analyzed, and the mechanism of the corresponding effect on the oxidation resistance of the coating at high temperature was discussed in detail.

2. Experimental

2.1. Sample Preparation

A cylindrical carbon anode block (Grade 1, Shenzhen Tailin Machinery Equipment Co., Ltd., Shenzhen, China.) with dimensions of φ50 mm × 50 mm was selected as the coated substrate material and compared with a sample after surface grinding and polishing by #240 abrasive paper. Subsequently, the cylindrical block was coated with the double-layered BSA/AO coating, and the schematic diagrams are shown in Figure 1. The coating slurry was synthesized as follows. The CMC solution was prepared by dissolving sodium carboxymethyl cellulose (CMC, decomposition temperature: 300 °C) in water at a mass ratio of 1:72. The raw powders, including B4C (1–10 μm, Macklin Reagent Co., Ltd., Shanghai, China.), SiO2 (~5 μm, Macklin Reagent Co., Ltd., Shanghai, China.), Al2O3 (~5 μm, Macklin Reagent Co., Ltd., Shanghai, China.), and albite (Na2O·Al2O3·6SiO2, 3000 mesh, Hengyuan New Materials Co., Ltd., Henan, China.), were separately added to the CMC solution at a powder-to-solution mass ratio of 3:5. The mixture was stirred for 2 h to form a uniform slurry. The designed chemical compositions of the slurry are listed in Table 1.
The samples were marked as 15BC, 20BC, 25BC, and 30BC according to the added B4C content, which was 15%, 20%, 25%, and 30% (in mass) in the inner layer in the B4C-SiO2–Albite (BSA)/Al2O3 (AO) composite coatings, respectively. And the corresponding inner BSA layers were labeled 15BSA, 20BSA, 25BSA, and 30BSA. The composite coatings were prepared in two steps. Firstly, the carbon block was coated with a ~120 μm BSA layer and subsequently dried at 80 °C for 2 h. Secondly, an outer ~130 μm AO layer was applied to the BSA-coated carbon, following by drying at 80 °C for 2 h and 120 °C for 10 h. The sample of the carbon block covered with the BSA/AO composite coating was available.

2.2. Characterization

The isothermal oxidation tests of the coated samples were conducted at 900 °C in an ambient furnace (KSL-1700X, Hefei Kejing Material Technology Co., Ltd., Hefei, China.), and the specimens were furnace-cooled after the designed duration. A bare carbon block also was exposed to be a comparison. Then the coated carbon blocks were weighed to obtain the mass before and after oxidation by an analytical balance (GL2004B (±0.1 mg), Shanghai Yoke Instrument & Meter Co., Ltd., Shanghai, China.), and the mass loss percentage was determined by the following calculated Equation (1), which is an important factor for evaluating the oxidation resistance of the coating.
Δ w = m 0 − m 1 m 0 × 100 %
where Δw is mass loss percentage of the sample after oxidation, %; m0 is the initial mass of the sample before oxidation, g; and m1 is the mass after oxidation, g.
The phase constituents of the samples were characterized via X-ray diffraction (XRD, D8 Advance, D8 Advance, Bruker AXS GmbH, Karlsruhe, Germany.) with Cu Kα radiation λ = 1.5406 Å at a scan speed of 6°/min. The microstructure and chemical composition were measured using scanning electron microscopy (SEM, S-3400N, Hitachi High-Technologies Corporation, Tokyo, Japan.) with energy dispersive spectroscopy (EDS). And the thermal stability of the coating was evaluated through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) from 25 to 1000 °C at 10 °C/min in air.

3. Results and Discussion

3.1. Analysis of Oxidation Performance

Figure 2 shows the mass loss of the carbon block with the composite coating during exposure at 900 °C. It is clear that the mass loss percentages are 0.27%, 0.11%, 0.20%, and 16.91% for the samples coated with 15BC, 20BC, 25BC, and 30BC after oxidation for 196 h (Figure 2a), respectively. And the weight loss ratios become relatively steady after exposure within 52 h, which are 0.23%, 0.10%, 0.17% and 0.68% for the four coated samples (Figure 2b). The loss percentages increase by only 0.04%, 0.01%, 0.03, and 16.22% for the coated samples during the exposure from 52 h to 196 h. However, it is more than 90.28% for the uncoated carbon block after 24 h of oxidation from the comparability test. The average mass loss rates are about 0.35, 0.14, 0.26, and 21.95 (mg/cm2·h) for the coating samples, respectively. The application of the BSA/AO composite coating can significantly protect the carbon block from oxidation at high temperature.
The weight loss initially decreases with more B4C addition and then increases when the B4C content is more than 25 wt% in BSA. It is noted that the samples coated with 25BC and 30BC coatings have a mass gain within the initial 1 h exposure (Figure 2b), resulting from the formation of B2O3 due to the fact that more B4C reacts with the O2. The specimen with 30BC shows a linear tendency in mass loss, indicating that the 30BC coating exhibits poor oxidation resistance after long-term exposure at 900 °C. The coating with 20 wt% B4C in the inner BSA layer has the best oxidation resistance among the samples. It is indicated that the composite coatings with 15–25 wt% B4C in BSA show excellent oxidation resistance at high temperature, and more B4C in the BSA is not conducive to the oxidation resistance of the coating.

3.2. Analysis of Microstructure and Performance

The oxidation performance of the coating depends on its chemical composition and the phase constitution. The XRD patterns of the BSA/AO composite coatings before oxidation are presented in Figure 3. The inner BSA layer in the composite coating is composed of B4C, SiO2 and albite components due to the distinct diffraction peaks according to Figure 3a. And the B4C diffraction peak increases with more B4C addition. Figure 3b presents the XRD profiles of the BSA/AO composite coatings, showing that the phase constitution of the outer AO layer for the double-layered coating is mainly Al2O3. Further analysis indicates that the Al2O3 in the outer layer is the mixture of the α-Al2O3, γ-Al2O3, and θ-Al2O3 phases.
The surface and cross-sectional morphologies of the 20BC composite coating before oxidation are presented in Figure 4. The surface morphology of the inner BSA coating shows a relatively compact and uniform morphology, as shown in Figure 4a. The B4C particles are dispersed evenly in the BSA layer. The cross-sectional morphologies show that the adhesions of the BSA/substrate carbon block and BSA/AO are continuous and compact (Figure 4b). It can be seen that there are certain holes inside the two layers, which is beneficial for enhancing the ductility of the ceramic coating. According to the line scanning result of the Si element, it is easy to determine that the thicknesses of the BSA and AO layers both are about 130 μm. The uniform, compact BSA/AO composite coating can be available through the slurry brushing method.
Figure 5 shows the XRD profiles of the coatings after oxidation at 900 °C. As for the inner BSA coating after exposure for 1 h, it is mainly composed of amorphous component due to the fact that little diffraction peak can be detected, except for two weak peaks of SiO2 and albite (Figure 5a), which is completely different from what is shown in Figure 3a. It is indicated that a series of inter-reactions occurred in the coating during exposure. The outer AO layer is mainly composed of the Al2O3 phase, as shown in Figure 3b, indicating that the AO layer is of good thermal stability at high temperature. Furthermore, it is worth noting that there are obvious amorphous peaks around the diffraction of 15°, showing that there are certain amorphous component diffused into the outer layer.
Figure 6 displays the macroscopic morphologies of the samples with different B4C content after oxidation for 196 h at 900 °C. The 15BC and 20BC coatings show a relatively integral appearance compared to that of 25BC and 30BC. However, there is an evident amorphous component on the surfaces of the coatings with more B4C (Figure 6c,d), attributed to the outward diffusion of the glass with a low melting point [33,34]. However, the good fluidity of the glass will damage the strength of the outer Al2O3 coating frame. Then more cracks and outward infiltrated glass will be detected on the surface of the 30BC (Figure 6d). As for 15BC, it is possible that not enough glass component forms inside the composite coating, which is consistent with the relatively weak diffraction peaks of the amorphous component in 15BC among the samples shown in Figure 5b.
Figure 7a–d show the cross-sectional morphologies and the corresponding Si mapping of 20BC samples after oxidation at 900 °C for 1 h, 52 h, 100 h, and 196 h, respectively. The distribution of Si element in the outer AO layer indicates the zones filled with the outward-diffused glass from the inner BSA. The diffusion zone (DZ) is more compact than the top zone without the glass due to the filling and wetting of the amorphous component. The chemical composition of the glass in the DZ (Figure 7h) is 59.2 wt% O, 1.7 wt% Na, 18.6 wt% Al, and 20.5 wt% Si. The thickness of the DZ in 20BC is about 15.9 μm after exposure for 1 h. And it grows to 84.8 μm after 100 h duration, while it is 91.7 μm after 196 h of oxidation. The DZ thickening shows a linear law when exposed to high temperature for the initial 100 h (Figure 7i). The glass shows slow infiltration speed during 100–196 h of exposure. The thickening rates of the DZs are ~0.85 μm/h and 0.07 μm/h at the initial 100 h and the following 100 h exposure, respectively. The possible reason maybe related to the increasing viscosity of the glass in the infiltration layer and the inhibition effect on O2 diffusion [35,36]. This is helpful to enhance the service life of the composite coating against high-temperature oxidation.
According to Figure 7d–g, the thicknesses of the DZs are 60.3 μm, 91.7 μm, 98.1 μm and ~130 μm for 15BC, 20BC, 25BC, and 30BC after 196 h duration (Figure 7j), respectively. The glass in 30BC has infiltrated throughout the outer AO layer, which is consistent with which is shown in Figure 6d. More B4C addition promotes the formation and penetrating of the glass due to the low melting point and good fluidity.
The filling and wetting of the amorphous component are greatly influenced by the amount of B4C in the BSA layer. The chemical compositions of the BSA layers are listed in Table 2. The chemical compositions of the BSA layers after 1 h oxidation are close to those before exposure. However, oxygen significantly increases due to the inter-reaction of the O2 and B4C [37,38]. This then promotes the formation of glass rich in B and Si. It is noted that the amounts of the Na and Al in BSA layers after 196 h of oxidation increase compared to those after 1 h duration, resulting from the outward diffusion of the amorphous component. Meanwhile, the content of Si remains stable. The inter-reactions among the B4C, albite, and O2 lead to the formation of glass rich in B-Si and precipitating oxides rich in Na and Al. The steady level of Si in BSA indicates surplus albite and good stability of the glass layer during exposure.

3.3. Analysis of Mechanism

The composite coating has good oxidation resistance according to the above discussion, attributed to the rapid formation of an amorphous glass layer with an excellent oxygen-blocking diffusion property. The reaction of the mixtures such as the B4C-SiO2–Albite powders and B4C-SiO2–Albite-Al2O3 powders can be examined through the TG/DSC testing, as shown in Figure 8. The mixture of B4C-SiO2–Albite powders is consistent with that of the initial 20BSA layer before oxidation. The B4C-SiO2-Albite–Al2O3 composite powders are the designed 20BSA powders with Al2O3 powder at a 1:1 mass ratio. The melting points of the three components of the BSA layer are all higher than ~1100 °C. However, the mixture of them will react when heated higher than 579.1 °C, resulting in increasing the mass gain of the mixture powders (Figure 8a). The reaction peak temperature is 747.8 °C, and the temperature at the end of significant mass gain is 874.1 °C. This is owing to the reaction of B4C and O2 at high temperature, as shown in Equation (2), resulting in the capture of O and loss of C from B4C, and then the increase in the reaction system [39]. It is reported that the Na+ from albite can effectively lower the reaction temperature of the formation of glass by breaking the silica tetrahedron [40]. And the evaporation of the liquid B2O3 at higher than 874.1 °C is due to the increasing heat absorption trend according to the DSC curve and Equation (3) [41].
B4C + 4O2 = 2B2O3 (l) + CO2
B2O3 (l) = B2O3 (g)
The addition of Al2O3 powder does not distinctly change the reaction that occurs in the B4C-SiO2–Albite mixture powders, as shown in Figure 8b. It is worth noting that the mixture of B4C-SiO2–Albite-Al2O3 powders begins to melt at about 563.9 °C, slightly lower than that of the B4C-SiO2–Albite powders. The melting peak temperature is 759.1 °C, and it is 866.5 °C at the end of significant weight gain. When heated higher than 866.5 °C, the mixture shows a chemical reaction equilibrium for the flat DSC curve, indicating that the B4C-SiO2–Albite-Al2O3 powders exhibit good thermal stability at high temperature after the glass forming. The addition of Al2O3 into the B4C-SiO2–Albite powders can promote the formation of the amorphous component at a relatively low temperature, protecting the substrate from oxidation [42]. Furthermore, the existence of Al2O3 also can inhibit the evaporation loss of B2O3 and keep the glass more stable [43,44]. It can be concluded that certain Al2O3 addition is beneficial to generate the glass BSA layer and enhance the oxidation resistance of the composite coating.
Figure 9 illustrates the schematic of the microstructure evolution for the composite coating during exposure at high temperature. The BSA and AO layers in the BSA/AO composite coating are relatively compact and uniform before oxidation. During exposed to high temperature, such as 900 °C, the B4C in the BSA mixed powders will rapidly react with the O2 to form B2O3, leading to the formation of amorphous glass with a low melting point and good fluidity. Then the glass BSA layer can be generated quickly within the initial 1 h due to the sufficient B and Si [45], being an excellent oxygen diffusion barrier to inhibit O2 infiltration. Furthermore, the fluid mobility of the glass BSA mixture will diffuse into the outer poly-porous AO layer, resulting in the production of the glass-filled frame porous Al2O3 zone (Figure 9b). The Al2O3 does not react with the diffused glass, but keeps it more stable against oxidation and evaporation loss. Certain diffusion of the glass is helpful to increase the self-healing ability of the coating. The formation of the glass infiltration layer then can effectively prevent further loss of the boron in the inner BSA layer, enhancing the long-term oxidation resistance property of the composite coating. It can be concluded that the application of the double-layered BSA/AO composite coating is a promising strategy to protect the substrate carbon block from oxidation during high-temperature exposure.

4. Conclusions

A double-layered B4C-SiO2-Albite/Al2O3 (BSA/AO) coating can be successfully prepared using the slurry brushing method. And B4C has a great influence on the formation of glass and diffusion behavior, and then significantly affects the oxidation resistance of the coating. The double-layered BSA/AO composite coating is a promising strategy to protect the substrate carbon block from oxidation at high temperature.
(1)
The B4C addition promotes the formation of the amorphous component in the composite coating, which is helpful to improve the oxidation resistance of the composite coating due to the excellent oxygen diffusion barrier.
(2)
The addition content of B4C greatly affects the oxidation resistance property of the coating due to the amount of formed amorphous glass, attributed to the fluidity and the diffusion of the glass. The optimal addition content is about 20 wt% in the inner BSA layer. The 20 wt% BSA/AO composite coating shows the best oxidation performance, owing to only about 0.11% mass loss after exposure for 196 h at 900 °C.
(3)
The formation of the infiltration layer effectively prevents the further loss of the B element, keeps the glass stable, and enhances the long-term oxidation resistance property of the composite coating. The average mass loss rate is about 0.14 mg/cm2•h for the coating with 20 wt% B4C after 196 h duration.

Author Contributions

Conceptualization, T.L. (Tianquan Liang); formal analysis, P.C. and H.H.; investigation, P.C., Q.L. and H.W.; data curation, P.C. and Q.L.; writing—original draft preparation, P.C.; writing—review and editing, T.L. (Tianquan Liang), P.C. and T.L. (Tao Liu); supervision, T.L. (Tianquan Liang), Y.H. and H.H. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the Guangxi Science and Technology Base and Talent Special Project (AD25069063, AD25069078) and Innovation Project of Guangxi Graduate Education (YCSW2024036).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Data are contained within the article.

Conflicts of Interest

The authors declare no conflict of interest.

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Coatings 15 00688 g001
Figure 1. Schematic diagram of preparing BSA/AO composite coating.
Figure 1. Schematic diagram of preparing BSA/AO composite coating.
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Coatings 15 00688 g002
Figure 2. Mass loss curves of samples over time at 900 °C: (a) 196 h and (b) the initial oxidation stage within 52 h corresponding to the rectangle in (a).
Figure 2. Mass loss curves of samples over time at 900 °C: (a) 196 h and (b) the initial oxidation stage within 52 h corresponding to the rectangle in (a).
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Coatings 15 00688 g003
Figure 3. XRD pattern of the coatings before oxidation: (a) the inner BSA layers and (b) the BSA/AO composite coatings.
Figure 3. XRD pattern of the coatings before oxidation: (a) the inner BSA layers and (b) the BSA/AO composite coatings.
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Figure 4. The surface and cross-sectional morphologies of the 20BC composite coating before oxidation: (a) the surface morphology of the inner 20BSA layer and the magnified microstructure image of the corresponding rectangular region, (b) the cross-sectional morphology of the 20BC coating.
Figure 4. The surface and cross-sectional morphologies of the 20BC composite coating before oxidation: (a) the surface morphology of the inner 20BSA layer and the magnified microstructure image of the corresponding rectangular region, (b) the cross-sectional morphology of the 20BC coating.
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Coatings 15 00688 g005
Figure 5. XRD patterns of the coatings exposed at 900 °C: (a) inner BSA layers after oxidation for 1 h and (b) the BSA/AO composite coatings after 196 h of oxidation.
Figure 5. XRD patterns of the coatings exposed at 900 °C: (a) inner BSA layers after oxidation for 1 h and (b) the BSA/AO composite coatings after 196 h of oxidation.
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Figure 6. The macrographs of the BSA/AO composite coatings on samples after oxidation for 196 h at 900 °C (a) 15BC, (b) 20BC, (c) 25BC, and (d) 30BC.
Figure 6. The macrographs of the BSA/AO composite coatings on samples after oxidation for 196 h at 900 °C (a) 15BC, (b) 20BC, (c) 25BC, and (d) 30BC.
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Coatings 15 00688 g007
Figure 7. The cross-sectional morphologies and the corresponding Si mapping of samples: (a–d) 20BC after oxidation at 900 °C for 1 h, 52 h, 100 h, and 196 h, respectively. And (e–g), 15BC, 25BC, and 30BC after a duration of 196 h and (h) the microstructure of the diffusion zone corresponding to the rectangle in (d). The thicknesses of the diffusion zones in the AO layer for (i) 20BC after exposure for different hours and (j) the four samples after 196 h of oxidation.
Figure 7. The cross-sectional morphologies and the corresponding Si mapping of samples: (a–d) 20BC after oxidation at 900 °C for 1 h, 52 h, 100 h, and 196 h, respectively. And (e–g), 15BC, 25BC, and 30BC after a duration of 196 h and (h) the microstructure of the diffusion zone corresponding to the rectangle in (d). The thicknesses of the diffusion zones in the AO layer for (i) 20BC after exposure for different hours and (j) the four samples after 196 h of oxidation.
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Coatings 15 00688 g008
Figure 8. TG/DSC plots of coating materials: (a) B4C-SiO2–Albite mixed powders and (b) B4C-SiO2-Albite/Al2O3 (1:1 wt.%) mixture.
Figure 8. TG/DSC plots of coating materials: (a) B4C-SiO2–Albite mixed powders and (b) B4C-SiO2-Albite/Al2O3 (1:1 wt.%) mixture.
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Coatings 15 00688 g009
Figure 9. Schematic of microstructure evolution for the composite coating under high-temperature conditions: (a) pre-exposure state; (b) post-exposure state.
Figure 9. Schematic of microstructure evolution for the composite coating under high-temperature conditions: (a) pre-exposure state; (b) post-exposure state.
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Table 1. The chemical compositions of the coating slurries (wt%).
Table 1. The chemical compositions of the coating slurries (wt%).
SamplesInner BSA LayerOuter AO Layer
B4CSiO2AlbiteAl2O3
15BC154045100
20BC204040100
25BC254035100
30BC304030100
Table 2. The chemical compositions of the BSA layer (wt%).
Table 2. The chemical compositions of the BSA layer (wt%).
Exposure/h ONaAlSi
0 h15BC53.42.13.940.6
20BC53.91.83.840.4
25BC56.31.03.339.4
30BC58.90.72.438.0
1 h15BC62.72.32.132.9
20BC64.11.62.032.4
25BC65.31.31.831.6
30BC66.71.11.730.5
196 h15BC59.03.73.833.5
20BC60.13.34.632.0
25BC59.53.15.831.7
30BC60.81.86.331.2
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MDPI and ACS Style

Chen, P.; Luo, Q.; Wang, H.; He, H.; Liu, T.; Huang, Y.; Liang, T. Effect of B4C Content on the Oxidation Resistance of a B4C-SiO2–Albite/Al2O3 Coating at 900 °C. Coatings 2025, 15, 688. https://doi.org/10.3390/coatings15060688

AMA Style

Chen P, Luo Q, Wang H, He H, Liu T, Huang Y, Liang T. Effect of B4C Content on the Oxidation Resistance of a B4C-SiO2–Albite/Al2O3 Coating at 900 °C. Coatings. 2025; 15(6):688. https://doi.org/10.3390/coatings15060688

Chicago/Turabian Style

Chen, Pengbin, Quanhao Luo, Haoze Wang, Huan He, Tao Liu, Yingheng Huang, and Tianquan Liang. 2025. "Effect of B4C Content on the Oxidation Resistance of a B4C-SiO2–Albite/Al2O3 Coating at 900 °C" Coatings 15, no. 6: 688. https://doi.org/10.3390/coatings15060688

APA Style

Chen, P., Luo, Q., Wang, H., He, H., Liu, T., Huang, Y., & Liang, T. (2025). Effect of B4C Content on the Oxidation Resistance of a B4C-SiO2–Albite/Al2O3 Coating at 900 °C. Coatings, 15(6), 688. https://doi.org/10.3390/coatings15060688

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