Porous layer
First Claim
Patent Images
1. A method for forming a surface layer on a substrate, comprising the steps of:
- providing a substrate having a copper surface cathode;
depositing a surface layer on the surface of the substrate by electrodeposition from a copper anode in a solution of copper sulphate and 1.5M sulpheric acid, the surface layer comprising a porous wall structure defining and separating macro-pores that are interconnected in the general direction normal to the surface of the substrate and that have a diameter greater than 5 μ
m and less than 1000 μ
m, wherein the diameter of the pores gradually increases with distance from the substrate, and wherein the porous wall structure comprises dendritically ordered copper nanoparticles; and
modifying the porous wall structure to a continuous branched structure formed of the dendritically ordered copper nanoparticles that have been modified by annealing at 500°
C. for 5 hours to increase a grain size of the nanoparticles and reduce a boundary effect of the nanoparticles,wherein a boiling surface comprising the surface layer on the substrate maintains stable performance for over 80 hours in a pool of saturated R134a at a pressure of 4 bar and at a heat flux between 0.1 W/cm2 and 10 W/cm2 so as to have a surface superheat temperature difference of less than 0.3°
C. at a heat flux of 1 W/cm2 and a surface superheat temperature difference of less than 1.5°
C. at a heat flux of 10 W/cm2.
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Abstract
Heat exchange device with a boiling surface comprising a porous surface layer arranged on a solid substrate, the porous surface layer comprises a porous wall structure defining and separating macro-pores that are interconnected in the general direction normal to the surface of the substrate and have a diameter greater than 5 μm and less than 1000 μm wherein the diameter of the pores gradually increases with distance from the substrate wherein the porous wall structure is a continuous branched structure.
19 Citations
6 Claims
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1. A method for forming a surface layer on a substrate, comprising the steps of:
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providing a substrate having a copper surface cathode; depositing a surface layer on the surface of the substrate by electrodeposition from a copper anode in a solution of copper sulphate and 1.5M sulpheric acid, the surface layer comprising a porous wall structure defining and separating macro-pores that are interconnected in the general direction normal to the surface of the substrate and that have a diameter greater than 5 μ
m and less than 1000 μ
m, wherein the diameter of the pores gradually increases with distance from the substrate, and wherein the porous wall structure comprises dendritically ordered copper nanoparticles; andmodifying the porous wall structure to a continuous branched structure formed of the dendritically ordered copper nanoparticles that have been modified by annealing at 500°
C. for 5 hours to increase a grain size of the nanoparticles and reduce a boundary effect of the nanoparticles,wherein a boiling surface comprising the surface layer on the substrate maintains stable performance for over 80 hours in a pool of saturated R134a at a pressure of 4 bar and at a heat flux between 0.1 W/cm2 and 10 W/cm2 so as to have a surface superheat temperature difference of less than 0.3°
C. at a heat flux of 1 W/cm2 and a surface superheat temperature difference of less than 1.5°
C. at a heat flux of 10 W/cm2. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification