Pores-Sealing Coating for Molten Metal Bath
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Solution Overview
Problem
Existing methods for forming pores-sealing layers on thermal spray coating films in molten metal baths are prone to micro cracks and pore formation due to solvent evaporation, leading to permeation of molten metal and adhesion of dross, which compromises the integrity and longevity of the coating.
Innovation Solution
A method involving a mixed solution of aluminum dihydrogen phosphate and inorganic particles with a layered hexagonal crystal structure added to a silica sol solution, applied and fired to form a glassy pores-sealing material that seals cracks and pores, reducing micro cracks and enhancing adhesion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a binder solution is used as a raw material for the pores-sealing layer, then the bonding between ceramic particles can be strengthened, but the solvent evaporates by firing and thus the volume is reduced and minute cracks (micro cracks) are generated in the pores-sealing layer
Solution Approach 1:
The invention changes the chemical composition parameters of the pores-sealing layer by incorporating specific ratios of SiO2 (30-70 wt%), Al2O3 (10-40 wt%), and other metal oxides (10-40 wt%), optimizing the material properties to achieve both strong bonding and crack-free structure during firing
Solution Approach 2:
The invention uses a composite material system combining multiple ceramic oxides (SiO2, Al2O3, TiO2, ZrO2, etc.) with controlled particle size distributions and chemical compositions to create a pores-sealing layer that maintains integrity while providing strong particle bonding
2Quantity of substance
If the solvent in the binder solution is evaporated by firing, then the volume is reduced, but minute cracks (micro cracks) are generated in the pores-sealing layer
Solution Approach 1:
The invention controls the chemical composition parameters including SiO2 content (30-70 wt%) and Al2O3 content (10-40 wt%) to regulate the firing behavior and volume stability, preventing excessive shrinkage and micro crack formation while maintaining effective pore sealing
3Reliability
If fired fine particles are used to fill pores and cracks, then the pores can be sealed, but gaps (pores) are formed between the resulting fired fine particles due to solvent evaporation
Solution Approach 1:
The invention utilizes controlled porous structures with specific pore size distributions and fills them with appropriately sized ceramic particles, creating a hierarchical pore sealing system that prevents molten metal penetration while maintaining layer integrity
Solution Approach 2:
The invention creates a composite structure combining fired fine particles with a binder matrix containing specific ratios of SiO2, Al2O3, and other metal oxides, forming an integrated pores-sealing layer that eliminates gaps between particles
4Reliability
If the in-bath roll is made to resist reaction with molten metal, then corrosion resistance is improved, but dross adhesion to the roll surface increases
Solution Approach 1:
The invention applies different functional properties to different regions of the in-bath roll surface: the base layer provides corrosion resistance through cermet or ceramic coating, while the pores-sealing layer surface provides dross release properties through its specific ceramic composition and microstructure
Solution Approach 2:
The invention uses a composite coating structure where the pores-sealing layer combines SiO2, Al2O3, and other metal oxides in specific ratios to create a surface that simultaneously resists molten metal corrosion and prevents dross adhesion through its chemical composition and surface characteristics
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 solution effectively prevents micro cracks and pore formation, reducing molten metal permeation and dross adhesion, thereby improving the durability and performance of the thermal spray coating films in molten metal baths.
Implementation Method 1
a silica sol solution, and a mixed solution in which aluminum dihydrogen phosphate and inorganic particles having a layered hexagonal crystal structure are added to the silica sol solution
Implementation Method 2
applying or spraying, to a cermet thermal spray coating film formed on a base material or an oxide-based ceramic thermal spray coating film formed on a base material, a mixed solution obtained by adding aluminum dihydrogen phosphate and inorganic particles having a layered hexagonal crystal structure to a silica sol solution as a solution for sealing pores of the thermal spray coating film, and firing the mixed solution which is applied or sprayed to the thermal spray coating film
Data Source
AI summary
It is an object to provide a method for producing a member for a molten metal bath which is less likely to form minute cracks and pores in a pores-sealing coating film, and to provide a method for producing a member for a molten metal bath which can restrain adhesion of an alloy such as dross. The method for producing a member for a molten metal bath is characterized by applying or spraying, to a cermet thermal spray coating film formed on a base material or an oxide-based ceramic thermal spray coating film formed on a base material, a mixed solution obtained by adding aluminum dihydrogen phosphate and inorganic particles having a layered hexagonal crystal structure to a silica sol solution as a solution for sealing pores of the thermal spray coating film, and firing the mixed solution which is applied or sprayed to the thermal spray coating film.