Heat transfer tube having rare-earth oxide superhydrophobic surface and method for manufacturing the same
The present disclosure relates to a heat transfer tube having rare-earth oxide deposited on a surface thereof and a method for manufacturing the same, in which the rare-earth oxide can be deposited on the surface of the heat transfer tube to implement a superhydrophobic surface even under the high temperature environment and a plurality of assembled heat transfer tubes can be coated by coating a complex shape by depositing rare-earth oxide using a method for dipping a surface of the heat transfer tube and coating the same, thereby reducing or preventing the heat transfer tubes from being damaged during the assembling of the heat transfer tubes after the coating.
1. A method for manufacturing a heat transfer tube having a rare-earth oxide superhydrophobic surface, comprising:
preparing a rare-earth coating solution including Ce(NO 3 ) 3 , peroxide, and water;
sonicating the heat transfer tube;
dipping the sonicated heat transfer tube into an acidic solution; and
dipping the heat transfer unit into the rare-earth coating solution to form a coating layer on a surface of the heat transfer tube,
wherein the coating layer includes a rare-earth oxide.
2. The method of claim 1 , wherein the preparing of the rare-earth coating solution includes:
preparing a mixture by mixing the Ce(NO 3 ) 3 , the peroxide, and the water;
sonicating the mixture;
agitating the mixture at least 500 rpm for 10 to 30 minutes after the sonicating of the mixture; and
stabilizing the mixture for 50 to 70 minutes after the agitating.
3. The method of claim 1 , further comprising performing a hydrocarbon contamination after the dipping the heat transfer unit.
4. The method of claim 3 , wherein the performing includes:
providing an airtight container including alkene of C 10-20 or unsaturated fatty acid solution,
disposing the heat transfer tube dipped into the rare-earth coating solution in the airtight container, and
heating the airtight container to 40 to 60° C. for 6 hours or more.
5. The method of claim 3 , wherein the coating layer formed on the surface of the heat transfer tube includes a carbon coating layer.
6. The method of claim 1 , wherein the rare-earth oxide coating solution includes 4 to 9 wt % of Ce(NO3)3, 1.3 to 2 wt % of peroxide, and a balance of water.
7. The method of claim 1 , wherein the sonicating includes disposing the heat transfer tube in acetone and sonicating the heat transfer tube for 3 to 7 minutes, and thereafter disposing the heat transfer tube in ethanol and sonicating the heat transfer tube for 3 to 7 minutes.
8. The method of claim 1 , wherein the heat transfer tube includes a plurality of assembled heat transfer tubes.
9. The method of claim 1 , wherein the acidic solution includes 2M of hydrochloric acid (HCl).
10. The method of claim 1 , wherein in the dipping includes dipping the transfer tube in 2M of hydrochloric acid (HCl) for 20 to 40 seconds.
11. The method of claim 1 , wherein the dipping removes a metal oxide layer formed on the surface of the heat transfer tube.
12. The method of claim 1 , wherein the heat transfer tube includes copper or aluminum.
13. The method of claim 12 , wherein the heat transfer tube includes copper, and the heat transfer tube is dipped into the rare-earth coating solution for 20 to 40 minutes.
14. The method of claim 12 , wherein the heat transfer tube includes aluminum, and the heat transfer tube is dipped into the rare-earth coating solution for 30 to 120 minutes.
15. The method of claim 1 , wherein the rare-earth oxide of the coating layer includes CeO2.
16. The method of claim 1 , wherein a thickness of the coating layer is in the range of 100 to 400 nm.