摘要
目的为了提升AlN基板的散热性能,研究嵌入式一体化AlN平板热管的激光加工方法。方法通过飞秒激光微织构技术结合热处理工艺制备出AlN亲疏水组合表面,并组装嵌入式一体化平板热管,测试其传热性能。通过三维表面轮廓仪、SEM、EDS和XPS分别分析表面的三维轮廓、形貌、元素含量和化学成分,研究表面亲、疏水的形成机理。结果楔形亲疏组合AlN平板热管的启动时间、启动温度均最低,相较于全超亲水样品,启动时间降低了14.9%,启动温度降低了6.0%。楔形亲疏组合热管的热阻最低,热流密度最高。相较于全亲水热管,热阻降低了33%,热流密度提升了2%。结论AlN陶瓷表面经过激光织构会产生AlOx(多价铝氧化物),具有较高的表面能,呈超亲水状态。热处理能使表面充分氧化,降低表面能,呈超疏水状态。嵌入一体化AlN平板热管的设计和无化学激光选区微织构方法,为电子陶瓷基板的散热提供了一种新思路。
Liquid wicking is one of the key factors determining the heat dissipation capacity of heat pipe.The work aims to study the laser processing of embedding AlN flat heat pipes to enhance the heat dissipation performance of AlN substrates.An integrated flat heat pipe was designed to be embedded in a ceramic substrate.AlN ceramic,known for its high thermal conductivity,was utilized as the material for the capillary core on the plate surface.In the present processing,an ultrafast laser micro texturing technology was employed to fabricate highly-infiltrated integrated flat heat pipes,thereby enhancing heat transfer performance of the ceramic substrate.A superhydrophilic and superhydrophobic composite surface was created on AlN with femtosecond laser micro texturing technology.Additionally,the AlN was subsequently assembled into an embedded plate flat heat pipe to test its heat transfer performance.The heat flux and thermal resistance of the heat pipe were calculated according to the temperature change of measuring point and Fourier's heat conduction law.These three-dimensional surface profile,morphology,oxygen content,and chemical composition were analyzed with three-dimensional optical microscopy,SEM,EDS,and XPS to investigate the formation mechanism of the hydrophilic and hydrophobic surface.The results indicated that the wedge-shaped combination samples had the shortest start-up time and lowest start-up temperature.The samples exhibited a start-up time of approximately 80 s and a start-up temperature of around 81.5℃.Compared to the fully superhydrophilic sample,the start-up time and start-up temperature were reduced by 14.9%and 6.0%,respectively.Additionally,the wedge-shaped combination samples exhibited the lowest thermal resistance and the highest heat flux,with a thermal resistance of 0.0052 K/W and a heat flux of 1593.1 kW/m^(2).These values represented a 33%reduction in thermal resistance and a 2%increase in heat flux compared to the fully superhydrophilic sample.SEM observations revealed that after laser texturing and heat treatment,the surface of the AlN ceramic exhibited numerous laminar structures with micrometer-sized pores between them.The AlN surface was covered with scattered nano-villus clusters,which exerted a lifting effect on water droplets and rendered the superhydrophobic surface.However,subsequent micro texturing of the AlN ceramic surface led to the almost complete disappearance of nano-villus clusters,revealing a"bare"sheet structure,and resulting in a superhydrophilic surface.From a surface energy perspective,laser texturing of the AlN ceramic surface generated an inadequate amount of high surface-energy aluminum polyvalent oxide,leading to a superhydrophilic surface.Heat treatment in a constant-temperature oven at 120℃for 24 h,made the surface be oxidized completely.The reactions occurring on the sample surface might involve 2AlN→2Al+N2 and 4Al+3O_(2)→2Al_(2)O_(3),which subsequently reduced the surface energy and transformed it into a superhydrophobic state.This hybrid superhydrophilic and superhydrophobic surface is beneficial to the rapid transmission of liquid from evaporation end to condensation end in the flat heat pipe,thus enhancing heat transfer performance.The heat pipe fabricated in this study exhibits superior thermal response speed and stability compared to the fully superhydrophilic one,offering a promise for heat dissipation issues in microelectronic devices.
作者
娄德元
李珩
邱媛
江宏亮
杨东超
陈晨阳
董超帅
李腾
刘顿
LOU Deyuan;LI Heng;QIU Yuan;JIANG Hongiang;YANG Dongchao;CHEN Chenyang;DONG Chaoshuai;LI Teng;LIU Dun(Ultrafast Laser Processing Research Center,School of Mechanical Engineering,Hubei University of Technology,Wuhan 430068,China;Shenyang Aircraft Corporation,Shenyang 110034,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2024年第16期182-189,共8页
Surface Technology
基金
湖北省重点研发计划项目(2021BAA172)
湖北省轻工业绿色材料重点实验室开放基金(202107A03)
国家自然科学基金(52205148)。
关键词
ALN
飞秒激光
微织构
超疏水
超亲水
平板热管
传热性能
AlN
femtosecond laser
micro texturing
superhydrophobic
superhydrophilic
flat heat pipe
heat transfer performances
