High-Temperature Dielectric and Microwave Absorption Property of Atmospheric Plasma Sprayed Al2O3-MoSi2-Cu Composite Coating

Cheng Gao,Dayong Cai,Yangsheng Jiang,Jinyong Xu,Jia Ding

doi:10.3390/coatings11091029

Cheng Gao, Dayong Cai + Show 3 more

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https://doi.org/10.3390/coatings11091029

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Abstract

Al2O3-MoSi2 coating has excellent high-temperature stability. On this basis, Al2O3-MoSi2-Cu composite high-temperature absorbing coating was prepared by atmospheric plasma spraying method. The phase transition characteristics of Al2O3-MoSi2-Cu spraying feedstock under high temperatures were analyzed by thermogravimetric test, the phase analysis of coating was performed by an in situ XRD test at different temperatures, and the microstructure of the coating was characterized by SEM. The test results of high-temperature microwave absorption performance show that, in high-temperature air atmosphere, the Cu in the coating is gradually transformed into Cu2O by oxygen atom diffusion, and the microwave absorption performance of the coating gradually increases with the increase in temperature. The 1.7 mm-thick coating at 500 °C has the best absorbing performance with a reflection loss (RL) value of −17.96 dB and an effective absorbing bandwidth (RL < −10 dB) in X-band of 2.42 GHz. The prepared Al2O3-MoSi2-Cu composite high-temperature absorbing coating takes into account the dual advantages of high-temperature stability and high-temperature absorbing properties.

Highlights

With the rapid development of radar detection technology, absorbing materials have attracted more and more attention, especially high-temperature absorbing materials
Al2 O3 has the advantages of high hardness and high melting point, which is commonly used in the production of high-temperature resistant materials; after fully mixing with MoSi2, the high-temperature stability of MoSi2 can be enhanced
The results showed that the content of MoSi2 had an effect on the high-temperature resistance of Al2 O3 /MoSi2 coating

Summary

Introduction

With the rapid development of radar detection technology, absorbing materials have attracted more and more attention, especially high-temperature absorbing materials. The commonly used dielectric materials include Ti3 SiC2 [1], SiCf [2], and Al2 O3 -TiC [3], and the magnetic materials include Fe3 Si [4], Cr2 AlB2 [5], Fe@MoS2 [6], etc. The absorbing materials include SiCN(CNTs) [7] and SiCO@BN [8], and the absorbing coatings include. In this study Al2 O3 , MoSi2 , and Cu powders were used to prepare high-temperature absorbing coating by air plasma spraying. MoSi2 is often used as spraying feedstock for plasma spraying, which has good oxidation resistance, high-temperature resistance, wear resistance, and good dielectric properties [11,12], and is widely used in high-temperature oxidation resistant materials and coatings. Yan et al [13]

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Conclusion