Single-Layer Ceramic Coating for Medical Implants
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Solution Overview
Problem
Existing medical implants, particularly deformable ones like stents, face issues with coating stability under physical stress, leading to chipping and adverse cellular responses due to fretting and corrosion, and current multilayer coatings have high failure probabilities and costly quality management requirements.
Innovation Solution
A single-layer ceramic coating with varying nitrogen content regions, comprising an ion-implanted adhesion area, a nitride cross-sectional area, and an oxynitride outermost area, is applied using physical vapor deposition with a changing gas mixture to enhance adhesion and mechanical stability, eliminating interfaces and reducing the likelihood of scaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a multilayer coating is used to provide protective functionality, then the coating can offer different functional properties in different layers, but the number of interfaces increases leading to higher probability of scaling and coating failure
Solution Approach 1:
The patent merges multiple functional layers into a single continuous coating layer with a gradient structure. The coating transitions from a metal-rich adhesion layer at the substrate interface to a ceramic-rich wear-resistant layer at the surface, eliminating interfaces while maintaining diverse functional properties throughout the single layer.
Solution Approach 2:
The patent applies local quality by creating regions within the single layer that have different compositions and properties. The adhesion area has higher metal content for bonding, the cross-sectional area has intermediate composition for transition, and the outermost area has higher ceramic content for wear resistance, with each region optimized for its specific function.
2Quantity of substance
If the coating is made thinner to reduce material usage and cost, then production costs decrease, but the coating becomes more susceptible to chipping and wear
Solution Approach 1:
The patent changes the compositional parameters within the coating layer, creating a gradient from metal-rich to ceramic-rich regions. This allows the coating to achieve enhanced durability and chip resistance through compositional optimization rather than increasing thickness, maintaining material efficiency while improving performance.
3Reliability
If ion implantation is used to enhance adhesion, then the coating bonds better to the substrate, but the adhesion layer thickness must be precisely controlled within a narrow range
Solution Approach 1:
The patent uses ion implantation to modify the compositional parameters at the coating-substrate interface, creating an adhesion-enhanced region without requiring precise thickness control. The ion implantation process alters the chemical and physical properties of the adhesion area, providing strong bonding while allowing greater flexibility in coating deposition parameters.
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 coating significantly improves stability against chipping and mechanical stress, ensuring biocompatibility and extended implant lifespan by maintaining adhesion and preventing particulate formation, thus addressing the limitations of existing coatings.
Implementation Method 1
a single layer coating comprising an ion-implanted adhesion area (1, 2) located on the inner side of the layer
Implementation Method 2
A single-layer ceramic coating with varying nitrogen content regions, comprising an ion-implanted adhesion area, a nitride cross-sectional area, and an oxynitride outermost area, is applied using physical vapor deposition with a changing gas mixture
Data Source
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AI summary
The present invention relates to a single layer ceramic coating comprising a multiplicity of cross-sectional areas, wherein the area adjacent to a substrate carrying said coating is an adhesion area composed of a solid or a combination thereof and one area comprises a metal nitride (MXNY), wherein M is a solid transition metal of group IV B, V B or VI B of the periodic table of the elements, said one area being 0.1 to 25 nm thick, with X and Y being a number between 0 and 1, wherein X+Y is 1.