Two-Layer Anodic Oxide Coating for Engine Heat Insulation
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Solution Overview
Problem
Conventional anodizing treatments for aluminum-based materials face challenges in achieving both high heat insulation and corrosion resistance simultaneously, with existing methods requiring long treatment times and resulting in low formation efficiency, while also struggling to provide sufficient durability and impact resistance for internal combustion engine components.
Innovation Solution
A two-layer anodic oxide coating structure is formed using AC-DC superimposition electrolysis followed by direct-current electrolysis, where the first anodic oxide coating has a higher porosity for heat insulation and the second has a denser structure for corrosion resistance, enhancing durability and impact resistance, and improving coating formation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a porous anodic oxide coating is formed by direct-current electrolysis to improve heat insulation, then heat insulation properties are improved, but corrosion resistance deteriorates due to pore formation
Solution Approach 1:
The anodic oxide coating is divided into two distinct layers: a first porous layer formed by direct-current electrolysis for heat insulation, and a second dense layer formed by AC-DC superimposition electrolysis for corrosion resistance. This segmentation allows each layer to fulfill its specific function without compromising the other.
Solution Approach 2:
The coating structure combines two different anodic oxide layers with distinct properties - a porous layer for thermal insulation and a dense layer for corrosion protection - creating a composite structure that achieves both heat insulation and corrosion resistance simultaneously.
2Reliability
If a dense anodic oxide coating is formed to improve corrosion resistance, then corrosion resistance is improved, but heat insulation properties deteriorate due to reduced porosity
Solution Approach 1:
The coating is segmented into two functional layers where the first layer (porous) handles heat insulation and the second layer (dense) handles corrosion resistance, allowing both properties to coexist without compromise.
Solution Approach 2:
Different regions of the coating have different properties: the inner layer is porous for heat insulation while the outer layer is dense for corrosion resistance, with each layer optimized for its specific local function.
3Manufacturing precision
If conventional anodizing treatment is conducted to achieve desired porosity and film thickness, then coating quality is improved, but treatment time increases resulting in low formation efficiency
Solution Approach 1:
The coating formation uses periodic AC-DC superimposition electrolysis followed by direct-current electrolysis, creating a multi-stage periodic process that achieves high-quality coating with reduced total treatment time compared to conventional single-stage anodizing.
Solution Approach 2:
The first anodic oxide layer is formed as a preliminary step to establish the porous structure for heat insulation, which then serves as the base for forming the second dense layer, eliminating the need to form a thick dense layer from scratch and thus reducing total treatment time.
4Temperature
If multiple cylindrical pores are present in the anodic oxide coating to improve heat insulation, then heat insulation is improved, but durability and impact resistance deteriorate
Solution Approach 1:
The coating is segmented into a porous first layer for heat insulation and a dense second layer for durability and impact resistance, with the second layer protecting the porous structure from mechanical damage while maintaining thermal insulation properties.
Solution Approach 2:
The composite coating structure combines a porous thermal insulation layer with a dense protective layer, creating a material system that simultaneously achieves heat insulation and high durability/impact resistance.
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 method achieves high heat insulation, corrosion resistance, durability, and impact resistance for internal combustion engine components, while reducing the time and complexity of the anodizing process, thereby improving coating efficiency and preventing issues like adhesion failure and porosity degradation.
Implementation Method 1
In the porous layer of the anodic oxide coating, which is formed mainly by direct-current electrolysis
Implementation Method 2
an anodic oxide coating with a high porosity and a large film thickness is formed to lower the thermal conductivity
Data Source
AI summary
Provided are a method for an anodizing treatment on an aluminum-based material and a structure of an internal combustion engine which are provided with both high heat insulation properties and a high corrosion resistance, a high durability and a high impact resistance, and high water-repellent and oil-repellent functions. This method comprises the steps of: forming a second anodic oxide coating 2b by application of AC-DC superimposition electrolysis to an aluminum-based material 1; and, after the step, forming a first anodic oxide coating 2a by application of direct-current electrolysis to the aluminum-based material 1, wherein the second anodic oxide coating 2b is formed on the first anodic oxide coating 2a.