Anodized Heat Exchanger Fins With Submicron Bactericidal Surface
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Solution Overview
Problem
The mechanism of bacterial killing by nanopillars is unclear, and black silicon's strong bactericidal activity is difficult to utilize due to its poor mass productivity and brittleness, limiting its application in products like heat exchangers and metal members.
Innovation Solution
A heat exchanger and metal member with a porous anodized layer having a submicron-order uneven structure, featuring recessed portions and protruding portions, are developed, which provide a microbicidal surface for preventing fungal growth and sterilization, utilizing a surface treatment agent to enhance microbicidal activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If black silicon nanopillars are used for bactericidal activity, then strong bactericidal effect is achieved, but mass productivity is poor and material is brittle
Solution Approach 1:
The patent copies the bactericidal surface structure concept from black silicon and applies it to aluminum alloy through porous anodization, creating a scalable manufacturing process that maintains the nanoscale uneven structure's microbicidal effect while enabling mass production
Solution Approach 2:
The patent changes the material parameter from black silicon to aluminum alloy and modifies the surface treatment parameters (anodization voltage, time, electrolyte composition) to create nanopillars with two-dimensional size of 100-500 nm, achieving both bactericidal activity and manufacturability
2Reliability
If black silicon nanopillars are used for bactericidal activity, then strong bactericidal effect is achieved, but shapability is poor due to brittleness
Solution Approach 1:
The patent copies the bactericidal surface structure concept from black silicon and applies it to aluminum alloy through porous anodization, creating a scalable manufacturing process that maintains the nanoscale uneven structure's microbicidal effect while enabling mass production
Solution Approach 2:
The patent changes the material parameter from black silicon to aluminum alloy and modifies the surface treatment parameters (anodization voltage, time, electrolyte composition) to create nanopillars with two-dimensional size of 100-500 nm, achieving both bactericidal activity and manufacturability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The microbicidal surface effectively reduces bacterial counts and prevents fungal occurrence, improving the antimicrobial properties of heat exchangers, beverage dispensers, and food container lids without increasing manufacturing complexity or costs.
Implementation Method 1
reportedly, black silicon has 500 nm high nanopillars, and the physical structure of the nanopillars produces a bactericidal activity. Wings of cicadas and dragonflies have 240 nm high nanopillars.
Implementation Method 2
a porous anodized layer formed on the metal base
Data Source
AI summary
A heat exchanger includes a fin, the fin including a metal base and a porous anodized layer formed on the metal base. A surface of the porous anodized layer has a submicron-order uneven structure, the uneven structure including a plurality of recessed portions whose two-dimensional size viewed in a normal direction of the surface is more than 100 nm and less than 500 nm.