Amorphous Alloy Pipe Coating for High-Temperature Corrosion
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Solution Overview
Problem
High-temperature corrosion in thermal power plants and gas turbines leads to reduced durability and increased maintenance costs due to the degradation of pipes and components, particularly when biomass co-firing is used, which accelerates corrosion rates and causes peeling or cracking of existing thermal barrier coatings.
Innovation Solution
A pipe with a hollow tube body coated with an alloy layer containing Fe, Cr, Mo, B, C, Si, and Nb, forming an amorphous phase with a thermal expansion coefficient similar to the base material, providing enhanced corrosion and abrasion resistance through a thermally sprayed coating layer with a thickness of 100 μm to 600 μm and a high Vickers hardness of 700 to 1200 Hv.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional thermal barrier coatings are applied to pipes in high-temperature environments, then the pipes gain initial protection, but the coatings peel or crack due to thermal expansion mismatch and corrosion, reducing durability
Solution Approach 1:
The patent changes the fundamental parameter of the coating structure from crystalline to amorphous phase. This parameter change eliminates the thermal expansion mismatch problem that causes cracking and peeling, as amorphous materials have more uniform thermal expansion characteristics. The amorphous alloy coating maintains adhesion and integrity in high-temperature environments where conventional coatings fail.
Solution Approach 2:
The patent employs composite material design by creating an amorphous alloy coating containing multiple elements (Fe, Cr, Mo, B, C, Si, Nb) in specific proportions. This composite structure provides both corrosion resistance and mechanical stability, combining the benefits of different elements while avoiding the weaknesses of single-material coatings.
2Adaptability or versatility
If biomass co-firing is implemented to reduce greenhouse gas emissions, then renewable energy usage increases, but high-temperature corrosion rates increase dramatically, causing rapid degradation of heat exchanger pipes
Solution Approach 1:
The patent converts the harmful corrosive environment created by biomass co-firing into a manageable condition. By designing an amorphous alloy coating specifically resistant to the types of corrosion caused by biomass combustion (including chlorine-containing compounds), the harmful factors are neutralized, allowing the benefits of renewable energy usage to be realized without the detrimental effects.
Solution Approach 2:
The patent changes the chemical composition parameters of the protective coating to specifically address biomass-induced corrosion. The amorphous alloy contains elements (Cr, Mo, B, Si, Nb) in optimized proportions that provide resistance to the specific corrosive agents present in biomass combustion environments, including alkali metals and chlorine compounds.
3Reliability
If the coating layer is made thicker to improve corrosion resistance, then protection effectiveness increases, but manufacturing complexity and cost increase
Solution Approach 1:
The patent changes the phase structure parameter to amorphous, which provides superior corrosion resistance at thinner thicknesses compared to crystalline coatings. The amorphous structure's uniform composition and lack of grain boundaries prevent corrosion propagation, allowing effective protection with reduced coating thickness and simplified application processes.
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 amorphous alloy coating layer significantly extends the lifespan of pipes by preventing peeling and cracking, offering excellent corrosion resistance and abrasion resistance, thereby improving operational stability and reducing maintenance costs in high-temperature, corrosive environments.
Implementation Method 1
having an alloy including an amorphous phase
Implementation Method 2
forming a coating layer having an amorphous phase by thermally spraying the alloy powder
Data Source
AI summary
A pipe according to the present disclosure comprises: a hollow tube body in which fluids of different temperatures pass through the inside and outside thereof; and a coating layer which is provided on an external surface of the hollow tube body, and which has an alloy comprising an amorphous phase, wherein the alloy comprises Fe, and comprises at least one or more first component selected from the group consisting of Cr, Mo and Co, and at least one or more second component selected from the group consisting of B, C, Si and Nb.