Oxidation behavior and thermal stability of Cr2AlB2 powders

Zhang, Haiming; Xiang, Huimin; Dai, Fu‐Zhi; Zhang, Zhi-Li; Zhou, Yanchun

doi:10.1016/j.corsci.2020.108941

Cited by 27 publications

(37 citation statements)

References 51 publications

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“…32, the oxidation of Cr 2 AlB 2 powders exhibits an initial rapid linear oxidation followed by a slow parabolic oxidation behavior. Hence, after the initial rapid oxidation in a few minutes, oxidation rate and weight gain would become very low (lower parabolic rate constant K p of 0.07‐0.31 min −1/2 ) due to the formation of protective Cr 2 O 3 or Al 2 O 3 scale 32 . That is to say, after oxidation for 2 h, the phase compositions and contents would be stable with little change along with prolonging the oxidation time.…”

Section: Resultsmentioning

confidence: 99%

“…To test the effects of high‐temperature oxidation on EM wave absorbing properties of Cr 2 AlB 2 powders, oxidation treatments of Cr 2 AlB 2 powders at different temperatures were conducted using the methods reported in the authors' previous work 32 . The corresponding oxidation products, Cr 2 AlB 2 /Cr 2 O 3 , Cr 2 AlB 2 /CrB/Al 2 O 3 , and Cr 4 AlB 4 /Cr 2 AlB 2 /CrB/Al 2 O 3 composite powders, were obtained by isothermal oxidation of Cr 2 AlB 2 powders at 750, 900, and 1000°C for 2 h in flowing air, respectively.…”

Section: Methodsmentioning

confidence: 99%

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Electromagnetic wave absorbing properties of Cr₂AlB₂ powders and the effect of high‐temperature oxidation

et al. 2021

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The electromagnetic (EM) wave absorbing properties of Cr2AlB2 powders and those after high‐temperature oxidation were investigated. Coupling of magnetic and dielectric loss enables Cr2AlB2 with good absorption properties. The minimum reflection loss (RL) value is −44.9 dB at 8.5 GHz with a thickness of 2.7 mm, and the optimized effective absorption bandwidth (EAB) is 4.4 GHz (13.0‐17.4 GHz) with a thickness of 1.6 mm. After oxidation at 750, 900, and 1000°C for 2 h, the minimum RL values, respectively, are −23.9 dB (17.5 GHz, 1.5 mm), −41.4 dB (16.5 GHz, 1.5 mm), and −39.5 dB (8.0 GHz, 3.0 mm); and the corresponding EAB values, respectively, are 3.8 GHz (13.6‐17.4 GHz, 1.7 mm), 4.1 GHz (13.5‐17.6 GHz, 1.6 mm), and 4.4 GHz (13.0‐17.4 GHz, 1.7 mm). With an absorber thickness of 1.5‐4.0 mm, the EAB with a RL value of less than −10 dB can be tuned in a broad‐frequency range 5.0‐18.0 GHz, which basically covers C (4‐8 GHz), X (8‐12 GHz), and Ku (12‐18 GHz) bands. These results demonstrate that Cr2AlB2, as a high‐efficient and oxidation‐resistant absorber, is a promising candidate for microwave absorption applications and can retain good EM wave absorbing properties after high‐temperature oxidation.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Electromagnetic wave absorbing properties of Cr₂AlB₂ powders and the effect of high‐temperature oxidation

et al. 2021

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“…It is generally known that binary transition metal borides exhibit poor oxidation resistance, especially at a high temperature compared with ternary MAB phases. 15,51 With respect to defect recovery processes (based on Table 2), the most promising M 2 A 1 B 2 and M 3 A 1 B 4 phases for nuclear applications include Cr 2 AlB 2 , Cr 3 AlB 4 , Fe 2 AlB 2 , Fe 3 AlB 4 , Ni 2 AlB 2 , Rh 2 AlB 2 , Sc 2 AlB 2 , and Tc 2 AlB 2 . Considering the cost of the metals, Cr 2 AlB 2 , Cr 3 AlB 4 , Fe 2 AlB 2 , Fe 3 AlB 4 , and Ni 2 AlB 2 would be most promising for practical applications.…”

Section: Effects Of the Type Of Transition Metals On The Recombinatio...mentioning

confidence: 99%

“…More recently, ternary MAB (M = transition metal, A = aluminum, and B = boron) phases , have also been studied in many applications including nuclear reactor materials and magnets for energy applications . MAB phases have shown outstanding properties, such as good radiation and oxidation resistances, ,− magnetocaloric effect, − and electrocatalytic properties , while maintaining such benefits of binary MB phases as mechanical strength, ,, high decomposition temperature, and good thermal and electrical conductivities. − In addition, MBene, a new class of two-dimensional systems exfoliated from MAB phases, has been considered for promising materials in future energy applications, spintronics applications, and safe biological applications. , Many MAB phases have been theoretically predicted so far, while only a few of them have been synthesized. ,,− …”

Section: Introductionmentioning

confidence: 99%

Trends in the Behavior of Point Defects in MB and MAB Phases

Kim

Zhang

et al. 2022

Chem. Mater.

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Binary and ternary transition metal borides exhibit many outstanding properties, such as high melting temperature, high temperature strength, and electrical and thermal conductivities. However, defect properties have been rarely studied so far. Here, using first-principles calculations, we investigate structural effects on defect recovery processes in MB and MAB phases focusing on how Al layers and the type of transition metal affect annihilation of defects. First, we find that metal interstitials cannot be accommodated in MAB phases that have two Al layers, but instead they form antisites, which are largely immobile and therefore detrimental for defect recovery processes. We also find that the absence of Al layers in MB phases that have B chains leads to faster migration of metal interstitials and lower recombination barriers of B Frenkel pairs and hence contributes to efficient defect recovery processes of those MB phases as compared to the corresponding MAB phases. In the other types of MB and MAB phases that have B rings, we find that the role of Al layers varies depending on the type of metal elements. Lastly, we find that a larger M−B bond strength, which depends on the type of transition metal in MAB phases, correlates with a higher recombination barrier of B Frenkel pairs. Based on the discovered trends, we provide insights into the selection of materials to help design diverse applications where defect recovery processes are important.

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“…MoAlB, as the most studied MAB phase, has been widely investigated from theoretical simulations [3][4][5] to experimental studies, and exhibits attractive mechanical properties, high temperature properties, radiation tolerance, and ablation resistance [6][7][8][9][10][11][12]. So far, MoAlB as the only one in the MAB phase family has been demonstrated with better oxidation resistance than other Al-containing MAB phases (such as Fe 2 AlB 2 and Cr 2 AlB 2 ) at temperatures below 1300 ℃ due to J Adv Ceram 2022, 11(2): 0-0 www.springer.com/journal/40145 the formation of a dense and continuous α-Al 2 O 3 layer [13][14][15][16]. The oxidation resistance of MoAlB is even better than that of Ti 2 AlC and Cr 2 AlC MAX phases at 1100 ℃ [17][18][19].…”

Section: Introduction mentioning

confidence: 99%

Synthesis and properties of MoAlB composites reinforced with SiC particles

Zhang

et al. 2022

J Adv Ceram

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Novel MoAlB composites reinforced with 5–15 vol% SiC have been firstly prepared and characterized in the present study. The SiC reinforcement is stable with MoAlB at a sintering temperature of 1200 °C in Ar. The 5 vol% SiC/MoAlB composite exhibited improved mechanical properties and enhanced oxidation resistance. A flexural strength of 380 MPa and a Vickers hardness of 12.7 GPa were achieved and increased by 24% and 51%, respectively, as compared with those for MoAlB, indicating the enhanced strengthening effect of SiC. Cyclic oxidation tests at 1200 and 1300 °C for 10 h in air showed that the 5 vol% SiC/MoAlB composite has better oxidation resistance than MoAlB due to the formation of a dense and continuous scale composed of Al2O3 and SiO2, which prevents the oxygen inward diffusion and the evaporation of oxides. We expect that the general strategy of second phase reinforcing for materials will help to widen the applications of MoAlB composites.

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Oxidation behavior and thermal stability of Cr2AlB2 powders

Cited by 27 publications

References 51 publications

Electromagnetic wave absorbing properties of Cr₂AlB₂ powders and the effect of high‐temperature oxidation

Electromagnetic wave absorbing properties of Cr₂AlB₂ powders and the effect of high‐temperature oxidation

Trends in the Behavior of Point Defects in MB and MAB Phases

Synthesis and properties of MoAlB composites reinforced with SiC particles

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Oxidation behavior and thermal stability of Cr2AlB2 powders

Cited by 27 publications

References 51 publications

Electromagnetic wave absorbing properties of Cr2AlB2 powders and the effect of high‐temperature oxidation

Electromagnetic wave absorbing properties of Cr2AlB2 powders and the effect of high‐temperature oxidation

Trends in the Behavior of Point Defects in MB and MAB Phases

Synthesis and properties of MoAlB composites reinforced with SiC particles

Contact Info

Product

Resources

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Electromagnetic wave absorbing properties of Cr₂AlB₂ powders and the effect of high‐temperature oxidation

Electromagnetic wave absorbing properties of Cr₂AlB₂ powders and the effect of high‐temperature oxidation