Deformable Vitreous Coating on Metallic Substrates
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Solution Overview
Problem
Existing metallic substrates with vitreous coatings suffer from inflexibility, brittleness, and poor chemical stability, making them unsuitable for industrial applications that require mechanical and chemical protection, as well as thermoforming and use in hot aqueous media.
Innovation Solution
A two-stage heat treatment process is applied to an alkali metal silicate-containing coating sol on metallic substrates, first in an oxygen-containing or vacuum atmosphere to remove organic residues, followed by densification in a low-oxygen atmosphere to form a vitreous layer, enabling cold deformation and improved mechanical and chemical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the layer thickness is increased to >50 μm to obtain continuous, impervious layers, then the protection against corrosion and mechanical damage is improved, but the layers become inflexible and brittle, sensitive to bending, shock and impact, and flake off
Solution Approach 1:
The patent changes the chemical composition parameters of the glass coating by incorporating specific alkali metal ions (Li+, Na+, K+) and controlling the SiO2/B2O3 ratio, which fundamentally alters the mechanical properties of the coating, enabling it to be flexible and deformable even at thin thicknesses while maintaining protection
Solution Approach 2:
The patent creates a composite glass coating system combining multiple oxides (SiO2, B2O3, and alkali metal oxides) in specific proportions to achieve a material that simultaneously provides corrosion resistance, mechanical strength, and flexibility, resolving the contradiction between protection and deformability
2Reliability
If refractory systems (high-melting oxides such as ZrO2) are used to improve corrosion resistance, then the chemical stability is improved, but impervious layers cannot be produced via sol-gel processes
Solution Approach 1:
The patent changes the chemical composition by using alkali metal silicate-based glass coatings with controlled SiO2/B2O3 ratios and specific alkali metal ion content, which enables the coating to form impervious layers through sol-gel processes while maintaining corrosion resistance, making refractory oxides unnecessary
3Strength
If borosilicate glass layers are applied in layer thicknesses significantly below 1 μm to enable flexibility, then the deformability is improved, but sufficient mechanical and chemical protection is not ensured
Solution Approach 1:
The patent optimizes the chemical composition parameters (alkali metal ion content, SiO2/B2O3 ratio) to enhance the intrinsic quality of the glass coating, allowing thin layers to provide sufficient protection through improved density and reduced porosity rather than relying on increased thickness
4Strength
If layers are densified at 500° C. under air to achieve good scratch resistance, then the mechanical stability is improved, but the layers show discolorations and poor chemical stability
Solution Approach 1:
The patent employs an oxygen-free or low-oxygen atmosphere during the thermal densification process, which prevents oxidation and discoloration of the glass coating while maintaining chemical stability, eliminating the need for high-temperature air treatment
Solution Approach 2:
The patent changes the thermal processing parameters by conducting densification in controlled atmospheres (oxygen-free or low-oxygen) at optimized temperatures, which fundamentally alters the chemical stability and visual properties of the coating while maintaining mechanical strength
5Illumination intensity
If layers are densified at 500° C. under N2 atmosphere to avoid discolorations, then the visual appearance is improved, but very poor chemical stability is observed
Solution Approach 1:
The patent optimizes the chemical composition of the glass coating itself (alkali metal ion content, oxide ratios) to inherently improve chemical stability, allowing the coating to maintain both visual appearance and chemical resistance without relying solely on atmospheric control during densification
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 process produces a deformable vitreous coating with enhanced scratch resistance, hydrolytic stability, and visual appearance, allowing for the creation of flexible, corrosion-resistant layers that maintain performance under bending and exposure to water.
Implementation Method 1
thermal densification of the coating layer of (a) by a two-stage heat treatment... with formation of a vitreous layer
Implementation Method 2
the heat treatment comprises, in a first stage, a heat treatment carried out either (A) in an oxygen-containing atmosphere or (B) in a vacuum at a residual pressure of ≦15 mbar and, in a second stage, a heat treatment in a low-oxygen atmosphere up to full densification
Implementation Method 3
first stage, a heat treatment carried out either (A) in an oxygen-containing atmosphere or (B) in a vacuum at a residual pressure of ≦15 mbar... to remove organic residues
Data Source
AI summary
Metallic substrates having a deformable vitreous coating, obtainable by applying an alkali metal silicate-containing coating sol to the substrate and thermally densifying the layer thus obtained in a two-stage heat treatment process, the heat treatment being carried out, in the first stage, either (A) in an oxygen-containing atmosphere or (B) in a vacuum at a residual pressure of ≦15 mbar and, in the second stage, in a low-oxygen atmosphere up to full densification with formation of a vitreous layer.