Molded inorganic-fiber object
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Solution Overview
Problem
Inorganic fiber molded bodies used in high-temperature furnaces face issues with scale resistance, thermal shock resistance, mechanical shock resistance, and shrinkage when exposed to high-temperature heating conditions, leading to reduced heat-insulating performance and mechanical strength.
Innovation Solution
An inorganic fiber molded body is produced by impregnating a needle blanket of inorganic fibers with a liquid precursor of a spinel-based compound, represented by the formula Mg x Al y O 4, with an atomic ratio (y/x) from 6 to 10, drying, and then firing to convert the precursor into an oxide, resulting in a bulk density of 0.20 to 0.45 g/cm 3, which enhances scale, thermal, and mechanical shock resistance while preventing shrinkage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a coating agent comprising spinel is applied onto the surface of an inorganic fiber molded body to improve scale resistance, then scale resistance is improved, but adhesion between the coating layer and the molded body is weak causing peeling under thermal or mechanical shock
Solution Approach 1:
The invention merges the scale-resistant spinel component with the inorganic fiber structure by forming spinel within the fiber matrix itself through impregnation and heat treatment, rather than applying it as a separate coating layer. This integration ensures that the scale-resistant phase becomes an integral part of the molded body structure, eliminating adhesion issues between separate layers.
Solution Approach 2:
The inorganic fiber matrix acts as an intermediary between the spinel precursor and the final molded body structure. The fiber matrix provides a framework that holds the spinel-forming compounds in place during heat treatment, ensuring uniform distribution and strong integration of the spinel phase within the overall structure.
2Object-affected harmful factors
If spray application of coating agent is used to improve scale resistance, then scale resistance is improved, but working operation becomes complicated
Solution Approach 1:
The invention extracts the spinel-forming compounds from the separate coating application process and incorporates them directly into the inorganic fiber slurry before molding. This eliminates the need for subsequent spray coating operations and simplifies the overall manufacturing process to a single molding and heat treatment step.
Solution Approach 2:
The spinel precursor is incorporated into the fiber structure during the initial slurry preparation and molding stage, before the final heat treatment. This preliminary incorporation eliminates the need for subsequent coating operations, as the scale-resistant phase is already in place within the fiber matrix prior to firing.
3Object-affected harmful factors
If low-melting point compounds are produced by reaction between scales and inorganic fibers, then scale reaction occurs, but shrinkage and sintering of inorganic fibers are promoted causing reduction in thickness and heat-insulating property
Solution Approach 1:
The invention changes the chemical composition parameters of the inorganic fiber system by incorporating specific spinel-forming compounds (magnesium oxide and aluminum oxide in controlled ratios) that react with scales to form high-melting-point products rather than low-melting-point compounds. This compositional modification prevents the harmful shrinkage and sintering effects.
Solution Approach 2:
The invention converts the potentially harmful reaction between scales and inorganic fibers into a beneficial process by using spinel-forming compounds that react with scales to form protective, high-melting-point spinel phases. This transforms what would be a damaging reaction into a protective mechanism that enhances both scale resistance and dimensional stability.
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 resulting inorganic fiber molded body exhibits excellent thermal shock resistance, mechanical shock resistance, and scale resistance, maintaining structural integrity and heat-insulating properties under high-temperature conditions, making it suitable for use in high-temperature furnaces and skid pipes with complex geometries.
Implementation Method 1
impregnating a needle blanket of inorganic fibers with a liquid precursor of a spinel-based compound
Implementation Method 2
drying
Implementation Method 3
firing to convert the precursor into an oxide
Implementation Method 4
firing to convert the precursor into an oxide
Implementation Method 5
exhibits excellent thermal shock resistance, mechanical shock resistance
Implementation Method 6
exhibits excellent thermal shock resistance, mechanical shock resistance
Implementation Method 7
exhibits excellent thermal shock resistance, mechanical shock resistance, and scale resistance
Implementation Method 8
prevented from suffering from shrinkage when used under high-temperature heating conditions
Implementation Method 9
maintaining structural integrity and heat-insulating properties under high-temperature conditions
Data Source
AI summary
The present invention aims at providing an inorganic fiber molded body that is excellent in scale resistance, thermal shock resistance and mechanical shock resistance, and prevented from suffering from shrinkage when used under high-temperature heating conditions. The inorganic fiber molded body of the present invention is produced by impregnating a needle blanket of inorganic fibers with a liquid material of a precursor of a spinel-based compound represented by the general formula: MgxAlyO4 wherein an atomic ratio (y/x) is not less than 2 (y/x ≥ 2); drying the thus impregnated needle blanket; and firing the dried needle blanket to convert the precursor into an oxide thereof.