Hydroxyapatite Plasma Spray Material for Strong Adhesion
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Solution Overview
Problem
Existing plasma spray methods for forming hydroxyapatite films on metal substrates, such as those used in artificial joints, often result in films with low adhesive strength, leading to potential peeling and inflammation when subjected to load, due to the poor biocompatibility and fracture toughness of ceramics like hydroxyapatite.
Innovation Solution
A plasma spray material comprising hydroxyapatite powder with a mode diameter of 550 to 1000 nm and a pore diameter of 5000 nm or less, which is uniformly melted and adheres strongly to the substrate, enhancing the adhesive strength of the film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional plasma spray methods are used to form hydroxyapatite films on metal substrates, then the film can be formed with acceptable appearance, but the adhesive strength is low leading to peeling under load
Solution Approach 1:
The invention changes the physical parameters of the hydroxyapatite powder, specifically controlling the pore diameter to be 5000 nm or less and mode diameter to be 550-1000 nm. This parameter modification enables the material to achieve both high adhesive strength (15-20 MPa) and load resistance while maintaining film stability, resolving the contradiction between adhesive strength and reliability under load.
Solution Approach 2:
The invention utilizes controlled porosity in the hydroxyapatite powder particles, with pore diameters of 5000 nm or less. This porous structure allows for enhanced bonding with the metal substrate while maintaining the integrity of the film under load, simultaneously improving adhesive strength and film stability.
2Strength
If plasma spray conditions are significantly changed to improve adhesive strength, then bonding may improve, but thermal decomposition property and color tone are affected and production efficiency decreases
Solution Approach 1:
Instead of changing plasma spray process parameters, the invention modifies the material parameters (pore diameter and mode diameter of hydroxyapatite powder). This approach achieves high adhesive strength (15-20 MPa) without affecting thermal decomposition properties, color tone, or production efficiency, as the plasma spray conditions can remain standard.
Solution Approach 2:
The invention uses pre-prepared hydroxyapatite powder with optimized physical properties (pore diameter ≤5000 nm, mode diameter 550-1000 nm) that can be directly applied using standard plasma spray processes. This eliminates the need for complex process adjustments and maintains production efficiency while achieving superior adhesive strength.
3Adaptability or versatility
If ceramic materials like hydroxyapatite are used to improve biocompatibility, then biological adaptability increases, but fracture toughness remains low making the film susceptible to peeling
Solution Approach 1:
The invention modifies the physical parameters of hydroxyapatite powder (pore diameter ≤5000 nm, mode diameter 550-1000 nm) to enhance fracture toughness while maintaining biocompatibility. The controlled porosity and size distribution provide both biological adaptability and mechanical strength, allowing the film to resist peeling under load while remaining biocompatible.
Solution Approach 2:
The invention creates a composite structure where the hydroxyapatite powder with controlled pore structure forms a film on the metal substrate. The porous architecture provides both biocompatibility for bone integration and enhanced mechanical properties for load resistance, effectively combining biological and mechanical requirements.
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 proposed plasma spray material significantly increases the adhesive strength of hydroxyapatite films on metal substrates, improving their load resistance and maintaining high whiteness and appearance, making them suitable for implants like artificial joints.
Implementation Method 1
When a working gas such as an argon gas is supplied to an arc generated by applying a voltage between a cathode and an anode, the working gas is ionized. By supplying the biocompatible material into a plasma frame thus generated, the temperature and airflow of the plasma frame cause the molten biocompatible material to adhere to a metal substrate
Implementation Method 2
a plasma spraying method is as follows. When a working gas such as an argon gas is supplied to an arc generated by applying a voltage between a cathode and an anode, the working gas is ionized. By supplying the biocompatible material into a plasma frame thus generated, the temperature and airflow of the plasma frame cause the molten biocompatible material to adhere to a metal substrate to form a film of the biocompatible material
Data Source
AI summary
The purpose of the present invention is to provide a plasma spray material which is capable of forming a hydroxyapatite film that exhibits high adhesion strength with respect to substrates such as metal substrates. When used as a plasma spray material, hydroxyapatite powder having a modal diameter of 550-1000 nm in a pore diameter of at most 5000 nm as measured by a mercury intrusion method is capable of forming a hydroxyapatite film that exhibits high adhesion strength with respect to substrates such as metal substrates.