Carbide-Coated Graphite Refractory for Peel-Resistant Corrosion Control
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Solution Overview
Problem
Existing refractory members with carbide coatings on graphite bases suffer from poor corrosion resistance and adhesiveness due to thermal expansion coefficient differences, leading to peeling and cracking, and are susceptible to reactive gases in SiC monocrystal growth processes.
Innovation Solution
A refractory member with a carbide layer formed by applying an oxide to the graphite base, melting it, and impregnating the pores, followed by carbonization to create a composite region with alternating graphite and carbide phases, acting as a thermal expansion buffer and enhancing adhesiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a carbide coating is applied directly on a graphite material base, then corrosion resistance is improved, but adhesiveness deteriorates due to thermal expansion coefficient differences causing peeling and cracking
Solution Approach 1:
The invention creates a composite structure consisting of a graphite material base and a carbide layer formed through in-situ carbonization. The carbide layer is generated by disposing metal oxide particles on the graphite base, heating to melt the oxide, impregnating pores with the molten oxide, and carbonizing to form carbide phases. This composite structure maintains corrosion resistance while improving adhesiveness through the gradual carbonization process that creates strong bonding between the graphite base and the formed carbide layer.
Solution Approach 2:
The invention changes the physical and chemical parameters of the coating formation process. Instead of applying pre-formed carbide particles, metal oxide particles are disposed on the graphite base and then transformed in-situ through controlled heating. The oxide melts, penetrates pores, and carbonizes to form carbide phases, fundamentally changing the coating formation mechanism from physical deposition to chemical transformation, thereby improving both corrosion resistance and adhesiveness.
2Temperature
If a carbide coating is applied on graphite base, then heat resistance is improved, but the coating is susceptible to reactive gases in SiC monocrystal growth processes
Solution Approach 1:
The invention utilizes the porous structure of the graphite material base and controls the impregnation of molten oxide into these pores. The formed carbide layer maintains a composite structure with controlled porosity that provides both high-temperature resistance and reduced susceptibility to reactive gas penetration. The oxide impregnation process fills pores with carbide-forming material, creating a barrier against reactive gas diffusion while maintaining thermal stability.
3Strength
If metal oxide is disposed on graphite base and carbonized, then adhesiveness is improved through pore impregnation, but manufacturing complexity increases
Solution Approach 1:
The invention performs preliminary actions by disposing metal oxide particles on the graphite base before the actual carbide layer formation. The oxide particles are positioned in advance, then during controlled heating, they melt and automatically impregnate the pores of the graphite base. This preliminary disposition of oxide particles simplifies the overall process by eliminating the need for separate pore-filling operations and ensuring uniform carbide layer formation through the natural capillary action of molten oxide penetration.
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 refractory member exhibits improved corrosion resistance and adhesiveness, preventing peeling and cracking even with repeated heat cycles, and inhibiting reactive gas diffusion, thus extending durability.
Implementation Method 1
heating to melt the oxide
Implementation Method 2
impregnating the pores with the molted oxide
Implementation Method 3
carbonization to create a composite region with alternating graphite and carbide phases
Data Source
AI summary
Provided is a refractory member that is excellent in corrosion resistance and excellent in the adhesiveness of a carbide coating disposed on a surface of a graphite material base. The refractory member includes: a graphite material base; and a carbide layer disposed to coat at least a part of a surface of the graphite material base. In the refractory member, the graphite material base includes a graphite material phase and a pore, the carbide layer includes a composite region, and the composite region includes an alternating region in which a continuous graphite material phase of at least 50 μm or more and a continuous carbide phase of at least 50 μm or more alternately exist in a horizontal direction along an interface between the graphite material base and the carbide layer, as viewed in a cross section along the thickness direction of the carbide layer.