Platinum-Rhodium Vessel Hydrogen Control for Rhodium Defects
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Solution Overview
Problem
The formation of rhodium-rich defects in glass or glass ceramic materials during manufacturing processes using platinum-rhodium vessels is a persistent issue, as these defects are transitory and appear in quantities sufficient to warrant mitigation, especially in high-temperature glasses, where eliminating rhodium from the system is not feasible.
Innovation Solution
A method involving the use of a platinum-rhodium alloy vessel with controlled hydrogen partial pressure to manage oxygen levels at the melt interface, combined with the addition of multivalent compounds and stirring to minimize the formation of rhodium-platinum defects, and incorporating materials like tin oxide, iron oxide, or cerium oxide to counteract thermal, electrical, or composition cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a platinum-rhodium alloy vessel is used in the manufacturing process, then the vessel strength and resistance to corrosion are improved, but rhodium-rich defects are formed in the glass or glass ceramic material
Solution Approach 1:
The patent applies local quality by creating a hydrogen-rich atmosphere specifically at the melt-vessel interface region. This localized hydrogen environment prevents rhodium dissolution only at the critical interface area where defects originate, while maintaining the overall platinum-rhodium alloy composition and strength properties of the vessel.
Solution Approach 2:
The patent introduces a hydrogen atmosphere as an inert-like protective environment around the melt-vessel interface. This hydrogen atmosphere acts as a protective barrier that prevents oxidation and rhodium dissolution reactions, similar to how inert gases protect materials from harmful chemical reactions.
2Reliability
If the partial pressure of hydrogen is controlled outside the vessel, then the partial pressure of oxygen in the melt adjacent to the interface is controlled, but the system complexity increases
Solution Approach 1:
The patent employs self-service by utilizing the natural permeation properties of the platinum-rhodium alloy vessel wall. The vessel wall itself acts as a selective barrier that allows controlled hydrogen transport, eliminating the need for complex external pressure control systems. The system self-regulates hydrogen partial pressure through the inherent properties of the alloy material.
Solution Approach 2:
The vessel wall acts as an intermediary between the external hydrogen atmosphere and the molten glass. It mediates the hydrogen transport process, allowing controlled hydrogen permeation to the melt interface while blocking other substances, thus simplifying the overall control system.
3Stability of the object's composition
If multivalent compounds are added to the melt, then the formation of localized thermal, electrical, or composition cells is minimized, but the manufacturing process complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the melt through controlled addition of multivalent compounds. This changes the electrochemical properties of the melt to prevent cell formation, stabilizing the composition without requiring complex physical control systems.
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 approach effectively reduces the occurrence of rhodium-platinum defects, ensuring the produced glass or glass ceramic materials are substantially free of these defects, enhancing their quality for applications such as display and protective cover glass.
Implementation Method 1
providing a partial pressure of hydrogen outside the vessel relative to a partial pressure of hydrogen inside the vessel in an amount sufficient to control the partial pressure of oxygen in a region of the melt adjacent to the interface
Implementation Method 2
providing a partial pressure of hydrogen outside the vessel relative to a partial pressure of hydrogen inside the vessel in an amount sufficient to control the partial pressure of oxygen in a region of the melt adjacent to the interface
Implementation Method 3
stirring the melt in a fining vessel of the manufacturing process, and stirring the melt immediately after it exits the fining vessel
Data Source
AI summary
A method of minimizing the formation of a rhodium-platinum defect in a glass or glass ceramic material or in the melt thereof is provided. The method includes providing a vessel made of a platinum-rhodium alloy for use in a manufacturing process for obtaining the material, and an interface between the vessel and the melt is present. The method can include providing sufficient partial pressures of hydrogen outside and inside the vessel for controlling the partial pressure of oxygen in a region of the melt adjacent to the interface. A method of minimizing the formation of, or counteracting the impact of, a localized thermal, electrical, or composition cell in the melt during a manufacturing process is also provided. The method can include adding a multivalent compound to the melt, adding a mixer to the finer tube, adding a mixing step to the manufacturing process, or amplifying the mixing.