Refractory Alloy Coating for Stronger Biostable Medical Implants
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Solution Overview
Problem
Common metal alloys used in medical devices, such as stainless steel, cobalt-chromium alloys, and TiAlV alloys, have deficiencies in properties like strength, durability, biostability, and biocompatibility, which limit their effectiveness and safety.
Innovation Solution
A refractory metal alloy, including at least 20 wt.% of Mo, Re, Nb, or Ta, is used, optionally coated with a protective layer to enhance properties such as strength, durability, and biocompatibility, while maintaining or reducing the device's bulk and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If common metal alloys (stainless steel, cobalt-chromium, TiAlV) are used for medical devices, then ease of manufacture and availability are improved, but strength, durability, and biostability are insufficient
Solution Approach 1:
The patent employs composite material structures by combining refractory metal alloys (Mo, Re, Nb, Ta, W) with other metals or coatings to create multi-layer or composite constructions. This allows the device to achieve superior strength and durability properties of refractory metals while maintaining manufacturability through established alloying techniques and coating processes.
2Strength
If refractory metal alloys with high strength properties are used, then strength and durability are improved, but device weight and bulk increase
Solution Approach 1:
The patent applies refractory metal alloys and protective coatings selectively to specific regions or layers of the medical device rather than uniformly throughout. This localized application maintains the high strength and durability benefits where needed while minimizing overall device weight and bulk, resolving the contradiction between strength improvement and weight reduction.
3Strength
If refractory metal alloys are used to improve strength and radiopacity, then radial strength and radiopacity are improved, but biocompatibility and adverse tissue reactions are worsened
Solution Approach 1:
The patent introduces protective coatings as intermediary layers between the refractory metal alloy core and the biological environment. These coatings (such as oxide layers, ceramic coatings, or bioactive coatings) serve as mediators that maintain the high radial strength and radiopacity of the refractory metal while providing biocompatibility and reducing adverse tissue reactions, thus resolving the contradiction between mechanical performance and biological compatibility.
4Strength
If refractory metal alloys are used to enhance mechanical properties, then yield strength and fatigue life are improved, but device complexity increases
Solution Approach 1:
The patent utilizes parameter changes in the refractory metal alloy composition (adjusting the ratios of Mo, Re, Nb, Ta, W and other alloying elements) to optimize yield strength and fatigue life. By carefully controlling compositional parameters and heat treatment conditions, the patent achieves enhanced mechanical properties through modified material parameters rather than through complex multi-component constructions or elaborate manufacturing processes, thus improving strength while limiting device complexity.
Data Source
AI summary
A metal alloy that includes an enhancement coating material. The metal alloy includes rhenium and one or more additives. The enhancement coating is at least partially applied to the metal alloy by a physical vapor deposition (PVD) process, a chemical vapor deposition (CVD) process, an atomic layer deposition (ALD) process, a plasma-enhanced chemical vapor deposition (PE-CVD) process, ion implantation, direct energy deposition (DED), and/or thermal spray techniques like plasma arc spraying, flame spraying, high velocity oxy fuel spraying (HVOF). The enhancement coating is formed of a) 35-95 wt. % zirconium and wherein said enhancement coating includes ZrN, ZrNC, ZrOC or a combination of ZrN and ZrO2, b) 20-85 wt. % titanium and one or more of carbon, nitrogen, oxygen, rhenium, and silicon, c) 40-85 wt. % chromium and one or more of carbon, nitrogen, oxygen, rhenium, and silicon, or d) at least 60 wt. % carbon.