Artificial Joint Cup Coating with Nano-scale Multilayer DLC Film
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Solution Overview
Problem
High molecular weight polyethylene artificial joint cups exhibit low hardness and wear resistance, leading to bone lysis, loosening of prostheses, and shortened service life due to material limitations and processing challenges, with existing solutions like ceramic-ceramic or gold-gold joints having their own defects.
Innovation Solution
A nano-scale multilayer carbon film is applied to a high molecular weight polyethylene joint cup using a magnetron sputtering coating device, comprising a pure Ti bottom layer, a Ti-TiC transition layer, and a composite layer of alternately deposited graphite-like and diamond-like carbon films, enhancing binding force and hardness while addressing heat resistance and oxidation issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diamond-like carbon film is coated on high molecular weight polyethylene joint cup surface, then wear resistance is improved, but the polyethylene material is damaged due to poor heat resistance and easy carbonization
Solution Approach 1:
The patent changes the temperature parameter during coating deposition, maintaining it below 100°C to prevent thermal damage to the polyethylene substrate while still enabling effective coating adhesion and formation of the diamond-like carbon film with improved wear resistance
Solution Approach 2:
The patent introduces an intermediary treatment process (plasma treatment or chemical etching) between the polyethylene substrate and the diamond-like carbon coating, creating a transition layer that enhances coating adhesion without requiring high temperatures that would damage the polyethylene material
2Reliability
If crosslinking modification is applied to high molecular weight polyethylene, then wear resistance is improved, but oxidation and catalysis problems occur
Solution Approach 1:
The patent replaces chemical crosslinking methods (which cause oxidation and catalysis) with a physical coating approach using diamond-like carbon deposition, achieving wear resistance through the coating's inherent properties rather than chemical modification of the polyethylene
3Reliability
If ion injection crosslinking modification is applied, then wear resistance is improved, but ion injection depth is limited to 0.1-0.2μm
Solution Approach 1:
The patent creates a composite structure combining the polyethylene substrate with a diamond-like carbon coating layer, where the coating provides the wear-resistant properties that would otherwise require deep modification, achieving effective protection without needing deep ion injection
4Reliability
If physical filling mode is used to improve wear resistance, then wear resistance is improved, but tensile strength, shock strength and elongation at break are reduced
Solution Approach 1:
The patent segments the functional requirements by placing the wear resistance function in a separate diamond-like carbon coating layer, while the polyethylene substrate maintains its original mechanical properties, allowing each layer to optimize its specific function without compromising the other
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 significantly improves the wear resistance and service life of artificial joint cups by providing a high-hardness, self-lubricating nano-scale multilayer structure that maintains the mechanical properties of the polyethylene material, reducing wear and oxidation risks.
Implementation Method 1
a magnetron sputtering coating device for manufacturing the artificial joint cup
Implementation Method 2
Through a coating technology, additional properties may be added to a substrate material
Data Source
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AI summary
The present invention aims at improving and upgrading the present devices based on the low temperature magnetron sputtering coating devices. Starting from the material systems, this invention establishes a new material system and a manufacturing method thereof based on a high molecular weight polyethylene joint cup to solve the poor binding force problem between the film and the matrix, and the problems of easy oxidization and carbonization of high molecular weight polyethylene with low temperature magnetron sputtering technologies at the same time. On the above basis, the ultra-lubrication performance of graphite-like structure films and ultra-hardness of diamond-like structure films are utilized to construct a nano-scale multilayer structure DLC film alternately coated with a graphite-like film and a diamond-like film. The present invention improves the wear resistance of high molecular weight polyethylene joint cups, and restricts low accuracy of joints due to creeping by constructing a new artificial hip joint cup of ultra-wear-resisting nano-scale multilayer structure DLC film with high hardness and self-lubricating capability.