Chromium-Free Phosphate Coating for Grain-Oriented Steel
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The use of hexavalent chromium in phosphate solutions for grain-oriented electrical steel coatings is toxic and environmentally harmful, posing challenges for large-scale industrial applications and requiring costly safety measures, while attempts to omit it have been limited to laboratory scales.
Innovation Solution
A chromium-free phosphate solution is applied to grain-oriented electrical steel, containing a colloidal component and phosphoric acid esters as colloid stabilizers, which ensures homogeneous application and stable sol/gel transition during drying, reducing the need for hexavalent chromium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hexavalent chromium is added to phosphate solution, then homogeneous application and stable sol/gel transition are achieved, but toxicity and environmental harm increase
Solution Approach 1:
The patent removes hexavalent chromium from the phosphate solution formulation while maintaining the desired coating homogeneity and sol/gel transition stability through alternative chemical compositions, thereby eliminating the toxic component while preserving functional performance
Solution Approach 2:
The patent introduces alternative chemical compounds as intermediaries to replace hexavalent chromium's functional role in stabilizing the sol/gel transition and ensuring homogeneous application, using substances that provide similar technical effects without the associated toxicity
2Reliability
If hexavalent chromium is used in phosphate solution, then stable industrial application is achieved, but costly safety measures and environmental protection requirements are imposed
Solution Approach 1:
The patent eliminates hexavalent chromium from the phosphate solution, thereby removing the need for associated safety infrastructure and environmental protection systems while maintaining reliable industrial application through alternative chemical formulations
3Object-affected harmful factors
If hexavalent chromium is omitted from phosphate solution, then toxicity is reduced, but homogeneous application and stable sol/gel transition cannot be ensured
Solution Approach 1:
The patent employs alternative chemical compounds as intermediaries that perform the same technical function as hexavalent chromium in stabilizing sol/gel transition and ensuring homogeneous application, without introducing toxicity
Solution Approach 2:
The patent modifies the chemical composition parameters of the phosphate solution, adjusting concentrations and types of chemicals to achieve homogeneous application and stable sol/gel transition while maintaining chromium-free formulation
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
This method allows for the production of a homogeneous phosphate layer on grain-oriented electrical steel without hexavalent chromium, enhancing industrial scalability and safety while maintaining effective tensile stress and magnetic properties.
Implementation Method 1
The sol/gel transition takes place after the phosphate solution has been applied to the belt surface, i.e. during the drying process
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a method for producing a magnetic strip that is covered with a phosphate layer. According to said method, a phosphate solution is applied to the magnetic strip, said solution containing a colloid component and at least one colloid stabiliser (A) as an additive.