摘要
目的针对冷喷涂CuCrZr涂层与CuCrZr板材在界面处的开裂问题,采用Cu涂层为过渡层,并探究Cu过渡层对CuCrZr涂层组织及性能的影响。方法采用高压氮气为工作气体,使用冷喷涂技术在CuCrZr基板上先制备一层Cu涂层打底,再继续喷涂多层CuCrZr涂层。通过金相显微镜、扫描电镜、显微硬度仪和激光热导仪,对涂层的组织和性能进行表征。结果Cu+CuCrZr涂层与基板界面结合良好,涂层的孔隙率约为0.624%,CuCrZr颗粒的扁平率为(43.62±4.54)%。Cu涂层的平均硬度约为153HV,冷喷涂CuCrZr涂层的平均硬度约为173HV。采用Cu涂层打底获得的CuCrZr涂层的热导率随温度的升高而升高,在500℃时与基体相当。结论Cu过渡层促进颗粒与基体之间发生良好结合,有效防止Cu CrZr涂层与CuCrZr板材开裂。采用Cu+CuCrZr涂层能满足CuCrZr结晶器力学与导热性能的要求。
Cold spraying has become a potential technology for repairing continuous casting crystallizer due to its advantages of small thermal impact,no damage to the substrate and unrestricted shape of the repair workpiece.At present,the crystallizer material commonly used for continuous casting is CuCrZr alloy,but the thermal expansion coefficient difference between the CuCrZr substrate and the cold-hardened coating is large,and the interface between the coating and the substrate is very likely to crack under the service conditions of the crystallizer with rapid cooling and heating.Therefore,the introduction of Cu particles with good plastic deformation ability was considered as an intermediate layer between the cold sprayed CuCrZr coating and the CuCrZr substrate to solve the cracking problem at the interface of the CuCrZr coating,and the influence of the Cu transition layer on the organization and properties of the CuCrZr coating was investigated,so as to provide a new idea for the repair of the copper crystallizer by cold spraying.With high-pressure nitrogen as the working gas,compressed air as the powder feeding gas,cold spraying technology was used in the CuCrZr substrate to prepare a layer of Cu coating primer,and then a multi-layer CuCrZr coating was sprayed.The CuCrZr and Cu powder were spherical,with a particle size range of 10-100μm.The average size was 30.2μm and 34.4μm,respectively.The substrate material was CuCrZr,and sandblasting was performed before coating.The cold spraying distance was 20 mm,the spraying speed was 20 mm/s,the powder feeding rate was 20 g/min,the pressure was 3.4 MPa,and the temperature was 500℃.Axio Oberver A1m Zeiss inverted metallurgical microscope and scanning electron microscope were used to observe the coating organization,combined with Image-J software to count the coating porosity and flattening.A DHV-1000ZTRDT microhardness tester was used to characterize the coating hardness.The thermal conductivity was determined with a NETZSCH LFA-427 Laser Thermal Conductivity Meter at test temperature of 50℃,250℃,and 500℃,and the specimens wereϕ10 mm×2.7 mm discs.It was found that the Cu+CuCrZr coating was well combined with the interface of the substrate,and the thickness of the Cu coating was about 50μm,and the CuCrZr coating was deposited on the top of the Cu coating sequentially.The porosity of the coating was about 0.624%,and the flattening rate of CuCrZr particles was(43.62±4.54)%.The hardness of the CuCrZr substrate was about 160HV,and there was a work-hardening layer of the substrate near the interface,with the hardness of about 163HV-168HV,and the thickness of about 160μm.The average hardness of the Cu coating was about 153HV,and that of the cold-sprayed CuCrZr coating was about 173HV.The thermal conductivity of the coating increased with the increase of test temperature,which arrived at the value of the substrate at 500℃.The Cu transition layer promoted a good bonding between the coating and the substrate,and thus effectively prevented the cracking of CuCrZr coating from the CuCrZr plate.The use of Cu+CuCrZr coating can meet the mechanical and thermal conductivity requirements of the CuCrZr crystallizer.
作者
王博
余敏
吕培源
陈辉
WANG Bo;YU Min;LYU Peiyuan;CHEN Hui(Key Laboratory of Advanced Technologies of Materials,Ministry of Education,School of Materials Science and Engineering,Southwest Jiaotong University,Chengdu 610031,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2024年第17期196-201,共6页
Surface Technology
基金
四川省自然科学基金(2022NSFSC1933)
国家自然科学基金(51601157)。
