Nanostructuring of Additively Manufactured Stainless-Steel Surfaces for Superior Boiling Heat Transfer

Area of Science:

• Materials Science
• Thermal Engineering
• Surface Engineering

Background:

• Stainless steel is valuable for thermal applications in corrosive settings.
• Traditional nanostructuring methods are ineffective for stainless steel heat transfer augmentation.

Purpose of the Study:

• To develop a novel method for nanostructuring stainless steel for improved heat transfer.
• To investigate the heat transfer enhancement achieved through additive manufacturing and etching.

Main Methods:

• Fabrication of 304L stainless steel using directed energy deposition (DED).
• Application of a two-step chemical etching process using chloride species.
• Characterization of the resulting micro- and nanoscale surface structures.
• Experimental evaluation of heat transfer coefficient during pool boiling.

Main Results:

• Directed energy deposition created a metastable microstructure in 304L stainless steel.
• The etching process successfully generated a network of micro- and nanoscale surface structures.
• A 5-fold enhancement in the heat transfer coefficient was observed during pool boiling.
• Enhanced nucleation in etched cavities contributed to improved heat transfer.

Conclusions:

• Additive manufacturing combined with etching offers an effective route for stainless steel surface modification.
• The developed technique significantly boosts heat transfer efficiency in thermal systems.
• This approach holds promise for creating more compact and efficient thermal management solutions.