PECVD Coating for Ferromagnetic Lamination Stacks
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Solution Overview
Problem
Ferromagnetic lamination stacks in electric machines face corrosion and mechanical damage issues, especially when exposed to harsh environments and high-speed spinning, where existing anti-corrosive coatings fail to adhere effectively.
Innovation Solution
A method involving Plasma Enhanced Chemical Vapor Deposition (PECVD) is used to apply a thin protective coating, typically between 5-50 micrometers thick, made of ultrapure silicon carbide or diamond-like carbon, on ferromagnetic lamination stacks within a hermetic chamber at low temperatures, followed by surface rectification to ensure uniformity and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If anti-corrosive painting is applied to protect lamination stacks from corrosion, then corrosion protection is improved, but coating adhesion deteriorates at high rotation speeds
Solution Approach 1:
The patent changes the deposition parameters from conventional painting at room temperature to PECVD process at controlled temperatures (20-450°C), plasma power (50-500 W), and pressure (0.1-10 mbar). This transforms the coating application from a mechanical process to a controlled physical vapor deposition process, achieving uniform thin films with superior adhesion that can withstand high rotation speeds
Solution Approach 2:
The patent replaces the mechanical painting process with a plasma-based physical vapor deposition process. Instead of using brushes or sprays that rely on mechanical adhesion, the coating is deposited through plasma-enhanced chemical vapor deposition, creating a molecular-level bond between the coating and substrate that remains stable at high speeds
2Ease of manufacture
If conventional coating methods are used to protect lamination stacks, then coating application is simplified, but coating thickness becomes too thick (178-406 μm) and prone to damage at high speeds
Solution Approach 1:
The patent controls the coating thickness through precise adjustment of deposition parameters including plasma power, pressure, deposition time, and substrate temperature. This enables control of coating thickness within the range of 1-10 μm, providing sufficient protection while maintaining the low mass and balance required for high-speed operation
Solution Approach 2:
The patent creates a precise replica of the lamination stack surface topology through conformal deposition. The PECVD process deposits coating material that follows the exact contours of the underlying lamination structure, ensuring uniform protection without adding significant mass or altering the mechanical balance of the rotor
3Reliability
If surface preparation is intensified to improve paint adhesion, then coating adhesion may improve, but manufacturing complexity and time increase
Solution Approach 1:
The patent replaces mechanical surface preparation methods with plasma treatment and direct plasma deposition. The plasma process simultaneously cleans, activates, and deposits the coating in a single integrated step, eliminating the need for separate sandblasting, priming, and painting operations while achieving superior adhesion
Solution Approach 2:
The patent combines multiple surface preparation and coating functions into a single PECVD process step. The plasma environment simultaneously performs surface activation, contamination removal, and coating deposition, reducing the manufacturing process from multiple sequential steps to one integrated operation
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 provides robust protection against corrosion and mechanical damage without affecting the magnetic properties of the lamination stacks, enabling operation in harsh conditions without the need for design changes, ensuring reliable performance across various environmental pressures and temperatures.
Implementation Method 1
depositing a thin layer of protective coating on the lamination stack of ferromagnetic sheets through a method of Plasma Enhanced Chemical Vapor Deposition (PECVD) at a temperature lower than 150° C.
Implementation Method 2
inserting the component module into a hermetic chamber receiving an ionized gas
Data Source
AI summary
A method of protecting ferromagnetic lamination stacks of a component of an electric machine, comprises the following steps: creating a component module by arranging a laminations stack of ferromagnetic sheets into a housing, (b) protecting locations of the component module where coating is unwanted, (c) inserting the component module into a hermetic chamber receiving an ionized gas, (d) polarizing the component module to submit a fixed electric potential to the component module, (e) depositing a thin layer of protective coating on the laminations stack of ferromagnetic sheets through a method of Plasma Enhanced Chemical Vapor Deposition (PECVD) at a temperature lower than 150° C., (f) monitoring the deposition homogeneity and deposition thickness of the thin layer of protective coating until desired thickness, and (g) rectifying the surface of the thin layer of protective coating to have a uniform protective layer.