Multilayer Tool Coating for Corrosion and Abrasion Resistance
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Solution Overview
Problem
Current coatings for metal tools in plastic processing applications fail to effectively protect against combined corrosive and abrasive attacks, particularly from glass fiber reinforced plastics, due to defects in ceramic coatings that lead to corrosion and delamination, and lack of ductility and impact resistance.
Innovation Solution
A multilayer coating system comprising a corrosive resistant layer, an abrasive resistant layer, and a transition layer is applied, where the corrosive resistant layer is deposited closer to the substrate, the abrasive resistant layer is deposited further away, and the transition layer improves adhesion between the two, using materials like AlCrO, CrON, and Cr2O3, which enhances both corrosion and abrasive resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ceramic coatings are applied to protect against corrosion, then corrosion resistance is improved, but the coatings contain defects that lead to galvanic corrosion and delamination
Solution Approach 1:
The patent applies a composite coating system consisting of multiple layers with different materials and functions. The底层 layer provides corrosion protection through materials like aluminum chromium oxide, while the顶层 layer provides abrasion resistance through materials like chromium oxynitride. This composite structure allows each layer to perform its specialized function, preventing the galvanic corrosion and delamination issues that occur with single-layer ceramic coatings.
Solution Approach 2:
The coating is segmented into distinct functional layers: a corrosion-resistant底层 layer and an abrasion-resistant顶层 layer, separated by a transition layer. This segmentation allows each layer to be optimized for its specific function, with the corrosion layer protecting against chemical attack and the abrasion layer protecting against mechanical wear, thereby preventing the failure modes of single-layer coatings.
2Reliability
If hard ceramic coatings are used to resist abrasion, then abrasive resistance is improved, but the coatings lack ductility and impact resistance
Solution Approach 1:
The patent uses a composite coating system where the abrasion-resistant顶层 layer (e.g., chromium oxynitride) provides hardiness against wear, while the underlying corrosion-resistant layer and transition layers provide ductility and impact resistance. This composite structure allows the hard顶层 to resist abrasion while the softer underlying layers absorb impact energy and prevent catastrophic failure.
Solution Approach 2:
Different regions of the coating have different material properties optimized for their specific functions. The顶层 is made harder for abrasion resistance, while the underlying layers are made more ductile for impact resistance. This local differentiation of material properties allows the coating system as a whole to exhibit both high abrasion resistance and adequate ductility.
3Ease of manufacture
If single-layer ceramic coatings are applied, then deposition process is simplified, but the coatings cannot simultaneously provide high corrosion and abrasion resistance
Solution Approach 1:
The coating process is segmented into multiple deposition steps, each creating a layer with specific material composition and properties. The first layer is deposited with corrosion-resistant materials, followed by a transition layer, and finally an abrasion-resistant顶层 layer. This segmentation of the deposition process allows each layer to be optimized for its specific function, achieving simultaneous corrosion and abrasion resistance that cannot be obtained with a single-layer coating.
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 multilayer coating system significantly improves the durability of tools by providing high abrasive resistance, corrosion resistance, and ductility, reducing wear and corrosion, and extending the tool's lifespan by preventing delamination and maintaining performance under mechanical loads.
Implementation Method 1
physical vapor deposition (PVD) or chemical vapor deposition (CVD) titanium, aluminum and other carbide or nitride layers
Implementation Method 2
physical vapor deposition (PVD) or chemical vapor deposition (CVD) titanium, aluminum and other carbide or nitride layers
Data Source
AI summary
An improved coating used in plastic processing applications including a first layer system that includes at least one corrosion resistant material layer; a second layer system that includes at least one abrasion resistant material layers; and a transition layer provided between the first layer and the second layer. The coating is resistant to both abrasion and corrosion, while maintaining ductility and impact resistance.