Titanate Layer Calcium Gradient for Bone Repair Scratch Resistance
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Solution Overview
Problem
Existing bone repair materials face issues with apatite-forming ability degradation under high-humidity, high-temperature conditions, low scratch resistance, and prolonged apatite formation times, which affect their stability and bonding capabilities with living bone.
Innovation Solution
A bone repair material with a titanium or titanium alloy substrate and a titanate layer having a calcium gradient structure, formed through a process involving alkaline solutions, calcium ion exchange, and heat treatment, which enhances scratch resistance and apatite formation within 3 days in a living body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a titanate layer is formed on the substrate to enable apatite formation and bonding to living bone, then the material can bond to living bone via apatite, but the titanate layer is low in scratch resistance and prone to peel off during surgery
Solution Approach 1:
The patent creates a multi-layer structure where the titanate layer has different calcium concentrations at different depths. The surface region has high calcium concentration for apatite formation, while the deeper region has low calcium concentration for high scratch resistance and strong bonding to the titanium substrate. This local differentiation of properties resolves the contradiction between apatite-forming ability and scratch resistance.
Solution Approach 2:
The patent forms a composite titanate layer that combines two distinct regions: a surface region rich in calcium for apatite formation and a deeper region poor in calcium for mechanical strength and scratch resistance. This composite structure integrates the beneficial properties of both regions, achieving both high apatite-forming ability and high scratch resistance simultaneously.
2Duration of action of stationary object
If the material is exposed to high-humidity condition at high temperature for long time during storage, then the material can be stored in inventory, but the apatite-forming ability is lost
Solution Approach 1:
The patent performs preliminary heat treatment at high temperature (600-800°C) in a controlled atmosphere to form a stable, low-calcium titanate layer in the deeper region before storage. This preliminary action creates a thermally stable structure that prevents calcium diffusion and apatite degradation during subsequent high-humidity, high-temperature storage conditions, preserving apatite-forming ability long-term.
Solution Approach 2:
The patent changes the thermal and compositional parameters of the titanate layer through controlled heat treatment. By heating at 600-800°C in air or oxygen-containing atmosphere, the material transforms into a stable rutile-type titanate structure with reduced calcium content in the deeper region, which is resistant to degradation under storage conditions while maintaining surface apatite-forming ability.
3Area of stationary object
If apatite formation time is extended to 10 days for whole surface coverage, then complete apatite layer is formed, but organic components adhere to surface first and prevent bonding to living bone
Solution Approach 1:
The patent creates a calcium concentration gradient within the titanate layer, with high calcium concentration at the surface region that rapidly promotes apatite formation. This local quality enhancement at the surface allows complete apatite coverage to be achieved within 3 days instead of 10 days, preventing organic component contamination and ensuring timely bonding capability.
4Strength
If heat treatment is applied to improve scratch resistance, then the material becomes more resistant to scratching, but the apatite-forming ability deteriorates
Solution Approach 1:
The patent applies heat treatment selectively to different regions of the titanate layer. The deeper region undergoes heat treatment at 600-800°C to form a stable, low-calcium structure with high scratch resistance, while the surface region maintains higher calcium content for apatite formation. This localized differential treatment resolves the contradiction between scratch resistance and apatite-forming ability.
Solution Approach 2:
The patent segments the titanate layer into functionally distinct regions: a surface region optimized for apatite formation and a deeper region optimized for mechanical strength and scratch resistance. The heat treatment is applied differently to each segment, with the deeper region receiving intensive heat treatment for scratch resistance while the surface region retains calcium for biological activity.
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 material exhibits superior apatite-forming ability and high scratch resistance, ensuring rapid bonding to living bone and maintaining stability during storage and use in load-bearing applications.
Implementation Method 1
immersing the substrate in a second aqueous solution that does not contain phosphate ions but contains calcium ions
Implementation Method 2
heating the substrate in a dry atmosphere
Implementation Method 3
apatite is formed on the whole surface of the material within 3 days in a living body or in a simulated body fluid
Data Source
AI summary
A bone repair material being superior in apatite-forming ability and its stability in a storage and high in scratch resistance is disclosed. The material is produced by a method comprising the steps of: immersing a substrate made of titanium or a titanium alloy in a first aqueous solution that does not contain calcium ions but contains at least one cation selected from the group consisting of sodium ions and potassium ions and is alkaline; immersing the substrate in a second aqueous solution that does not contain phosphate ions but contains calcium ions; heating the substrate in a dry atmosphere; and treating the substrate with hot water of 60° C. or higher or with steam.