Core-Shell Iron Oxide Particles for Inductive Heating
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Solution Overview
Problem
Existing iron-silicon oxide particles used for inductive heating in magnetic fields have not achieved sufficient reduction in heating times, despite improvements, and there is a need for a material that can further shorten these times.
Innovation Solution
Core-shell particles with a crystalline iron oxide core and an amorphous silicon dioxide shell, doped with specific elements like aluminium, calcium, copper, magnesium, silver, titanium, zinc, and zirconium, optimized in composition and structure to enhance heating rates, produced through a flame pyrolysis process in a flow reactor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If iron-silicon oxide particles are used for inductive heating, then heating capability is achieved, but heating time is too long
Solution Approach 1:
The patent changes the chemical composition parameters by introducing specific doping elements (Al, Ca, Cu, Mg, Ag, Ti, Zn, Zr) in optimized amounts (0.1-5 wt%) into the iron oxide core. This compositional parameter change enhances the magnetic properties and heating efficiency of the particles, directly reducing the heating time while maintaining effective heating capability.
Solution Approach 2:
The patent creates a composite core-shell structure combining iron oxide core (providing magnetic heating capability) with silicon dioxide shell (providing stability and controlled release). This composite structure synergistically combines the heating efficiency of iron oxide with the stabilizing properties of silica, achieving faster heating times while preventing particle aggregation and improving dispersion.
2Productivity
If doping components are added to iron oxide core, then heating efficiency is improved, but particle composition complexity increases
Solution Approach 1:
The patent applies local quality by concentrating the doping elements specifically within the iron oxide core region, while maintaining a pure silicon dioxide shell. This localized doping approach enhances heating efficiency at the core level without requiring complex composition throughout the entire particle structure, thus improving productivity while controlling overall complexity.
Solution Approach 2:
The patent optimizes the concentration parameters of doping elements to a specific range (0.1-5 wt%) to achieve optimal heating efficiency. By precisely controlling these compositional parameters, the patent improves heating efficiency while avoiding excessive complexity that would result from higher concentrations or multiple doping elements.
3Reliability
If shell thickness is increased, then particle stability is improved, but heating rate decreases
Solution Approach 1:
The patent optimizes the shell thickness parameter to a specific range (1-50 nm) that balances stability and heating rate. This parameter optimization ensures the shell is thick enough to provide particle stability and prevent aggregation, yet thin enough to allow efficient heat transfer from the iron oxide core to the exterior, thus improving reliability without sacrificing heating rate.
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 optimized core-shell particles achieve significantly shorter heating times compared to prior art, with the best results obtained using aluminium or zinc as doping components, demonstrating improved phonon transport and heat conduction.
Implementation Method 1
inductive heating of adhesive bonds
Implementation Method 2
inductive heating in an alternating magnetic or electromagnetic field
Implementation Method 3
demonstrating improved phonon transport and heat conduction
Implementation Method 4
heat conduction
Implementation Method 5
amorphous shell composed of silicon dioxide
Data Source
AI summary
Core-shell particles containing crystalline iron oxide in the core and amorphous silicon dioxide in the shell and in whicha) the shell contains from 5 to 40% by weight of silicon dioxide,b) the core contains b1) from 60 to 95% by weight of iron oxide andb2) from 0.5 to 5% by weight of at least one doping component selected from the group consisting of aluminum, calcium, copper, magnesium, silver, titanium, yttrium, zinc, tin and zirconium,c) where the % by weight indicated are based on the core-shell particles and the sum of a) and b) is at least 98% by weight of the core-shell particles,d) the core has lattice plane spacings of 0.20 nm, 0.25 nm and 0.29 nm, in each case+/â0.02 nm, determined by means of HR-TEM.