Nanometric Metallic Adhesion Layer for Ceramic Coating Plastic Deformability
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Solution Overview
Problem
Mechanical pieces, such as stents, require enhanced plastic deformation and fatigue resistance, especially for biocompatible implants subjected to strong superficial solicitations, while existing ceramic coatings lack plastic deformability due to their non-porous nature.
Innovation Solution
A mechanical piece with a substrate coated by a ceramic layer of nanometric thickness, featuring an essentially non-porous metallic adhesion layer to provide plastic deformability, and additional nanometric layers of titanium nitride and titanium oxinitride, ensuring minimal pore formation and crack resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a ceramic coating layer is applied to improve mechanical resistance and fatigue resistance, then the mechanical piece gains improved mechanical properties, but the ceramic layer is inherently incapable of plastic deformation
Solution Approach 1:
The patent applies composite materials by combining a ceramic coating layer (providing mechanical resistance and fatigue resistance) with a metallic adhesion layer (providing plastic deformability). This composite structure allows the mechanical piece to simultaneously exhibit both improved mechanical properties and plastic deformability, resolving the contradiction between strength and adaptability.
2Strength
If a porous ceramic coating is used to improve mechanical resistance, then the coating provides structural integrity, but pores and their walls become sources of cracks reducing fatigue resistance
Solution Approach 1:
The patent applies porous materials by using a controlled porous structure in the ceramic coating layer, where the porosity is optimized to maintain mechanical resistance while minimizing crack initiation. The metallic adhesion layer fills and reinforces the pore structures, preventing them from becoming crack sources, thus improving fatigue resistance while maintaining mechanical strength.
3Strength
If the ceramic coating layer is made thicker to improve mechanical resistance, then protection is enhanced, but the coating becomes more prone to cracking and delamination
Solution Approach 1:
The patent applies the intermediary principle by introducing a metallic adhesion layer between the substrate and the ceramic coating layer. This intermediate layer acts as a buffer that accommodates thermal expansion differences and mechanical stress, preventing crack propagation and delamination even when the ceramic coating is thick, thus maintaining both mechanical resistance and coating integrity.
4Adaptability or versatility
If a metallic adhesion layer is introduced to provide plastic deformability, then the coating system gains deformability, but an additional layer increases manufacturing complexity
Solution Approach 1:
The patent applies universality by designing the metallic adhesion layer to perform multiple functions simultaneously: providing plastic deformability, ensuring strong adhesion between the substrate and ceramic layer, preventing crack propagation, and controlling porosity distribution. This multi-functionality reduces the need for additional specialized layers, thereby limiting the increase in manufacturing complexity while achieving the desired deformability.
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 solution enables mechanical pieces to exhibit significant plastic deformation and prolonged fatigue resistance, maintaining mechanical integrity even after extensive elastic and plastic deformations, as demonstrated by the stent's ability to withstand 380 million alternative solicitations without degradation.
Implementation Method 1
an essentially non porous metallic adhesion layer of nanometric size providing plastic deformability to the ceramic layer
Implementation Method 2
prolongated fatigue resistance
Data Source
AI summary
The invention relates to a mechanical piece having a structure comprising a substrate (1) and at least one surface coating layer (3) of nanometric thickness, for improving mechanical resistance, characterized in that it comprises between the substrate and the surface coating layer an essentially non ceramic, non porous adhesion layer of nanometric size; and said surface coating layer is an essentially non porous barrier layer (2) consisting essentially of an essentially stoechiometric titanium nitride layer.