Modified Copper Chromite Spinel Pigment CTE Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional copper chromite black pigments exhibit high coefficients of thermal expansion (CTE), leading to stress buildup at the enamel-substrate interface, which can cause fractures and require higher fusion temperatures, affecting the flow and shape of glass substrates.
Innovation Solution
A modified copper chromite black spinel pigment with a reduced CTE is achieved by incorporating secondary modifiers such as Al, Mg, and Zn into the CuMnCr core composition, controlling the firing profile, and optimizing the CuMnCr core composition to stabilize the cubic spinel structure at room temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional copper chromite black pigments are used, then the pigment provides black color and UV screening, but the high CTE causes stress buildup at the enamel-substrate interface leading to fractures
Solution Approach 1:
The patent modifies the chemical composition parameters of the spinel pigment by incorporating secondary modifiers (Al, Mg, Zn) alongside Cu, Mn, and Cr. This compositional parameter change reduces the CTE of the pigment to better match the glass substrate, thereby reducing thermal expansion mismatch and stress buildup at the interface.
Solution Approach 2:
The patent creates a composite spinel structure by combining multiple metal oxides (CuO, MnO2, Cr2O3, Al2O3, MgO, ZnO) in specific proportions. This composite material approach allows tuning of the CTE to achieve better thermal compatibility with the glass substrate while maintaining the black color and UV screening properties.
2Temperature
If conventional copper chromite pigments are used, then the pigment provides adequate black color, but the high CTE requires higher fusion temperatures that affect the flow and shape of glass substrates
Solution Approach 1:
By changing the compositional parameters of the pigment (incorporating Al, Mg, Zn modifiers), the CTE is reduced, which allows the enamel to fuse at lower temperatures. This parameter change in the pigment composition directly enables lower processing temperatures that preserve the shape and flow characteristics of the glass substrate.
3Reliability
If the CTE of the pigment is reduced to match the substrate, then stress buildup is minimized, but the composition complexity increases with secondary modifiers
Solution Approach 1:
The patent systematically varies the compositional parameters within defined ranges (e.g., Cu: 0.3-0.6, Mn: 0.1-0.3, Cr: 0.8-1.2, Al: 0.05-0.2, Mg: 0.05-0.2, Zn: 0.05-0.2) to achieve the desired CTE reduction. This parameter optimization approach balances composition complexity with performance, finding the minimum necessary modification to achieve stress resistance.
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 modified pigment reduces thermal expansion mismatch, minimizing stress at the enamel-substrate interface and allowing for lower fusion temperatures, while maintaining a darker black color and improved UV screening properties.
Implementation Method 1
block the transmission of sunlight through the glass to protect underlying adhesives from degradation by ultraviolet radiation
Implementation Method 2
The modified pigment reduces thermal expansion mismatch, minimizing stress at the enamel-substrate interface
Data Source
AI summary
Modified copper chromite spinel pigments exhibit lower coefficients of thermal expansion than unmodified structures. Three methods exist to modify the pigments: (1 ) the incorporation of secondary modifiers into the pigment core composition, (2) control of the pigment firing profile, including both the temperature and the soak time, and (3) control of the pigment core composition.