Magnesium Oxide Coating on Fe-Co Alloy for EDM Insulation Stability
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Solution Overview
Problem
Existing laminated cores with permendur ceramic coatings face issues of discoloration during electric discharge machining due to ceramic layer elution, leading to potential loss of electrical insulation, and melt-adhesion during thermal treatment, which affects magnetic characteristics.
Innovation Solution
Applying a magnesium hydroxide solution followed by baking at 600-900°C to form a magnesium oxide coating on a Fe—Co-based alloy base material, stabilizing the lattice structure and preventing elution, thereby maintaining electrical insulation and suppressing melt-adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ceramic layer is applied on permendur single layer material to improve electrical insulation, then electrical insulation between laminated single plates is improved, but the ceramic layer elutes during electric discharge processing causing discoloration and potential loss of electrical insulation
Solution Approach 1:
The invention changes the chemical composition parameters of the coating by using a specific alloy containing Cr, Mn, and Mo elements in defined ranges. This compositional parameter change creates a coating that forms a stable oxide layer resistant to elution during electric discharge processing, while maintaining electrical insulation properties.
Solution Approach 2:
The invention creates a composite material structure by forming an oxide coating layer on the permendur alloy base material. The coating layer consists of multiple oxides (Cr2O3, Mn3O4, MoO3) that work together to provide both electrical insulation and resistance to elution during processing, solving the contradiction between insulation and stability.
2Object-generated harmful factors
If thermal treatment is performed on Fe—Co-based alloy material to form magnesium oxide coating for preventing melt-adhesion, then melt-adhesion between single layer materials is prevented, but the lattice structure becomes unstable causing coating elution and discoloration
Solution Approach 1:
The invention extracts and eliminates the problematic magnesium oxide coating that causes lattice instability and elution. Instead, it uses a oxide coating formed from Cr, Mn, and Mo elements that naturally forms a stable structure without causing discoloration or elution during electric discharge processing.
Solution Approach 2:
The invention replaces the unstable magnesium oxide coating with a stable multi-element oxide coating that does not require frequent replacement or re-coating. The new coating maintains its integrity throughout the manufacturing and service life of the laminated core.
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 method ensures electrical insulation during electric discharge processing and prevents melt-adhesion during thermal treatment, preserving the magnetic characteristics of the laminated core.
Implementation Method 1
a baking step for baking the base material after the application step at 600-900° C. to form a magnesium oxide coating on the base material
Implementation Method 2
a two-stage thermal treatment is performed on a cold-rolled Fe—Co-based alloy material and a laminated core is produced from the thermally treated alloy material
Data Source
AI summary
A coated member manufacturing method includes: an application step for applying a magnesium hydroxide solution on a surface of a Fe—Co-based alloy base material; and a baking step for baking the base material after the application step at 600-900° C. to form a magnesium oxide coating on the base material. This coated member has, on a Fe—Co-based alloy base material, a baked coating of magnesium oxide having a lattice constant of 4.20-4.23 Å.