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大气等离子喷涂及固相反应法制备MnCoCu金属连接体防护涂层OACSTPCD

MnCoCu Protective Coatings of Metallic Interconnects Prepared by Atmospheric Plasma Spraying and Solid Reaction

中文摘要英文摘要

目的 锰钴尖晶石涂层可有效抑制金属连接体高温氧化、降低固体氧化物燃料电池(SOFC)性能衰减,但其成本较高,电性能和稳定性也需进一步提升.方法 本文拟采用大气等离子喷涂技术(APS)和固相反应法以金属粉末制备高电导率尖晶石涂层.通过Cu元素的添加,在尖晶石涂层中引入高电导率的铜锰尖晶石相,获得高电导率尖晶石涂层,并通过对涂层的相组成、表面截面形貌、元素分布、电性能等物性的表征,揭示 Cu 添加量及固相转变条件对尖晶石涂层性能的影响规律.结果 800℃热处理后涂层明显致密化、均匀化,涂层主相为CuxMn3-xO4(x=1,1.2,1.4)和MnCo2O4;在基体和涂层的界面处存在Cr富集,800℃氧化10 h后,含Cu量 12%(质量分数)的试样面比电导最高;氧化 100 h后,面比电导有所下降,含Cu量 12%(质量分数)试样仍具有最高的面比电导;经过还原的试样面比电导明显低于未还原样品,其原因在于还原过程中Cr元素产生扩散,氧化后生成了较多的低电导率相.涂层导电性随Cu含量的增加而增大,800℃时Cu含量为 12%(质量分数)的样品电导率可达 93.15 S/cm.结论 尖晶石涂层可通过APS制备的金属涂层经热处理后获得;涂层的相组成可以通过金属粉末成分进行调控;Cu的添加有效提高了涂层的电导率,且随Cu含量的增加而增大;经还原处理后的涂层更加致密,但导电性低于未还原样品.

Mn-Co spinel coating can effectively protect metallic interconnects of solid oxide fuel cells(SOFC)from oxidation at elevated temperature and thus can restrain the performance degradation of cells.But currently the cost of spinel is high,the electrical performance and stability need to be improved.In this paper,highly conductive spinel coatings were prepared from metallic powder through atmospheric plasma spraying(APS)and solid phase reaction.Cu-Mn spinel,a highly conductive phase,was introduced into the spinel coating by Cu-doping.The effect of Cu addition and doping condition on the properties of spinel coatings was studied according to phase composition,morphology,element distribution and conductivity.The results showed that coatings were obviously densified and homogenized after being heated at 800℃.The main phase of the obtained coatings was identified as CuxMn3-xO4(x=1,1.2,1.4)and MnCo2O4 according to the X-ray diffraction(XRD)analysis.For sample with 6wt.%Cu and 9wt.%Cu,CuO,Mn2O3 were also in the coating samples containing 6wt.%Cu and 9wt.%Cu content.A region with rich Cr was observed between the substrate and the spinel coating.Sintering at controlled temperature with H2 protection(a reduction process)could significantly improve the density of coatings.The conductance of samples was characterized according to the areal specific conductivity and the conductivity.The areal specific conductivity was obtained by an ohmmeter,including both the contribution of the metallic substrate,the coating and the Cr-enriched region between them.The sample with 12wt.%Cu exhibited the highest areal specific conductivity with value of 24.84 S/cm2 after oxidation for 10 h at 800℃.For all samples,being oxidized for a period more than 100 h,the measured areal specific conductivity decreased,but sample with 12wt.%Cu still presented the highest conductivity.Moreover,after a reduction process,the areal specific conductivity of the obtained samples was significantly lower than that of samples without reduction process.It was thought that an intensive diffusion of Cr happened during the reduction process which turned to low-conductive phases during the oxidation step.The conductivity of coatings was obtained via a four-probe method.It was found that the conductivity of oxidized coatings increased with the addition of Cu and the test temperature.At 800℃,the conductivity of the sample with 12wt.%Cu was as high as 93.15 S/cm,but when a reduction process was introduced before the oxidization,its conductivity decreased to 35 S/cm due to the intensive diffusion of Cr happened during the reduction,which introduced the Cr-enriched region and low conductive phases to the coating.In addition,the conductivity of coatings was found higher after a long-time sintering.Therefore,it can be concluded that highly conductive spinel coatings can be obtained by sintering the metallic coatings prepared by APS.The phase composition of obtained spinel coatings can be easily regulated by adjusting the composition of metallic powder.The addition of Cu can effectively improve the electrical conductivity of spinel coatings.The reduced coatings were significantly densified,but will lead a decrease both of areal specific conductivity and the coating conductivity.

杨壮壮;刘太楷;文魁;宋琛;张留艳;邓畅光;邓春明;刘敏

广东工业大学 材料与能源学院,广州 510640||广东省科学院新材料研究所 现代材料表面工程技术国家工程实验室,广州 510650||广东省科学院新材料研究所 广东省现代表面工程技术重点实验室,广州 510650广东省科学院新材料研究所 现代材料表面工程技术国家工程实验室,广州 510650||广东省科学院新材料研究所 广东省现代表面工程技术重点实验室,广州 510650广东工业大学 材料与能源学院,广州 510640

金属材料

大气等离子喷涂连接体防护尖晶石涂层MnCoCu涂层电导率

atmospheric plasma sprayinginterconnect protectionspinel coatingsMnCoCu coatingconductivity

《表面技术》 2024 (002)

175-183 / 9

国家重点研发计划(2022YFB4003601);广东省科学院建设国内一流科研机构行动专项资金(2019GDASYL-0102007);广东省科学院国际科技合作平台建设资金(2022GDASZH-2022010203-003);广东省基础与应用基础研究项目(2021B15120087) The China National Key R&D Program(2022YFB4003601);GDAS'Project of Building Domesctric First-class Scientific Research Institutions(2019GDASFYL-0102007);GDAS'Project of Science and Technology Development(2022GDASZH-2022010203-003);Guangdong Fundamental and Applied Research Foundation(2021B15120087)

10.16490/j.cnki.issn.1001-3660.2024.02.017

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