Rare Earth Electrolyte Coloring for Low-Reflectance Ceramic Coatings
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Solution Overview
Problem
Existing electrolytic coloring methods result in metal surfaces with thin oxide films and excessively high reflectance, lacking durability and decorative consistency.
Innovation Solution
A rare earth-based electrolytic coloring method involving anodic oxidation, high-frequency and high-voltage treatment, and specific electrolyte compositions to form a thick, low-reflectance ceramic film layer with improved metallurgical bonding and corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If existing electrolytic coloring methods are used, then the workpiece surface is colored, but the oxide film thickness is insufficient and reflectance is excessively high
Solution Approach 1:
The patent changes multiple parameters including voltage (increased to 300-440V), frequency (50-100 kHz), temperature (25-40°C), and electrolyte composition (sodium silicate 5-70g/L, potassium hydroxide 3-30g/L, rare earth salts 1-2g/L) to optimize the anodizing process and achieve the desired film thickness and reflectance reduction
Solution Approach 2:
The patent creates a composite oxide film containing rare earth elements (cerium, lanthanum, dysprosium, yttrium, erbium, or thulium) incorporated during the anodizing process, which modifies the film's optical and structural properties to reduce reflectance while increasing thickness
2Length of stationary object
If high voltage and high frequency are applied during electrolytic coloring, then the ceramic film layer thickness is rapidly increased, but the process complexity increases
Solution Approach 1:
The patent performs preliminary anodizing to form a base oxide film before applying high voltage and high frequency treatment, which simplifies the subsequent thickening process by providing a stable foundation for the ceramic film layer formation
Solution Approach 2:
The patent employs periodic cycling between high voltage (300-440V) and high frequency (50-100 kHz) modes during the electrolytic coloring process, allowing controlled film thickening while managing process complexity through structured operational phases
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 produces a ceramic film layer with reduced reflectance, enhanced corrosion resistance, and improved color consistency, achieving a surface reflectance of less than 5% and a thickness of 15-100 μm, suitable for applications requiring low reflectance and durability.
Implementation Method 1
placing a workpiece into an electrolytic tank for anodic oxidation, where a fine and uniform oxide film is formed on a surface of the workpiece after electrification
Implementation Method 2
The electrolytic coloring is a surface treatment technology for electrolytically coloring to-be-processed workpieces through a micro-arc oxidation process
Implementation Method 3
after the oxide film is broken down, melted, sintered, and reformed, a ceramic film layer forming a metallurgical bond to a substrate is generated
Implementation Method 4
Because sodium silicate, sodium tungstate, disodium ethylenediamine tetraacetic acid, and the rare earth salts are added into the electrolyte, the oxide film has a greater thickness and lower reflectance
Data Source
AI summary
A rare earth-based electrolytic coloring method, electrolyte, and alloy product are provided, where the method includes: after an oxide film is formed on a workpiece subjected to anodic oxidation in the electrolyte, rapidly increasing a voltage, and by using a constant-voltage mode, breaking down, melting, sintering, and reforming the oxide film cyclically multiple times under conditions of high frequency, a high voltage, and instantaneous high temperature, to generate a ceramic film layer metallurgically bonded to a substrate. The oxide film has a greater thickness and lower reflectance, and an appearance as a matte black anode, and has good color consistency and no chromatic aberration. Components of the electrolyte include sodium silicate at a concentration of 5-70 g/L, sodium tungstate at a concentration of 1-18 g/L, disodium ethylenediamine tetraacetic acid at a concentration of 2-10 g/L, and rare earth salts at concentrations of 1-2 g/L.