Amorphous Iron-Based Alloy Coating for Rotational Equipment
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Solution Overview
Problem
Conventional coatings for rotational equipment, such as injection screws and impellers, face issues with poor bonding strength between ceramic materials and metal substrates, leading to cracking and peeling due to brittleness and inadequate corrosion resistance.
Innovation Solution
An iron-based alloy coating with a composition of FeaCrbMocSidBeYf, where 48≤a≤50; 21≤b≤23; 18≤c≤20; 2≤d≤4; and 0<f≤2, is applied through thermal spraying and subsequent laser re-melting to form an amorphous coating with enhanced bonding strength and reduced porosity, maintaining amorphous structure and improving corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ceramic material is coated on the screws to improve corrosion resistance, then corrosion resistance is improved, but bonding strength between coating and substrate deteriorates
Solution Approach 1:
The patent applies composite materials by combining multiple elements (Fe, Cr, Mo, Si, B, Y) to create an iron-based alloy coating that integrates the benefits of both metal substrate and ceramic-like properties. The coating contains metallic phases for bonding strength and intermetallic compounds for corrosion resistance, resolving the contradiction between bonding strength and corrosion resistance through material composition design.
2Reliability
If ceramic material is coated on the screws to improve corrosion resistance, then corrosion resistance is improved, but the coating easily suffers cracking and peeling due to brittleness
Solution Approach 1:
The patent changes the chemical composition parameters of the coating by incorporating specific ratios of Fe (48-50%), Cr (21-23%), Mo (18-20%), Si (2-3%), B (2-4%), and Y (0.1-2%). These parameter adjustments create a coating with optimized mechanical properties that reduces brittleness while maintaining corrosion resistance, preventing cracking and peeling.
Solution Approach 2:
The patent utilizes phase transitions by controlling the formation of different phases during coating deposition and heat treatment. The coating contains a mixture of metallic phases (for ductility) and intermetallic phases (for corrosion resistance), where the phase distribution and morphology are controlled to prevent brittleness-induced cracking while maintaining protective properties.
3Ease of manufacture
If conventional crystalline coating is used, then coating can be formed, but porosity is high and corrosion resistance is insufficient
Solution Approach 1:
The patent changes the microstructural parameters by controlling the coating deposition process and subsequent heat treatment to achieve an amorphous or fine-grained crystalline structure instead of coarse crystalline structure. This parameter control reduces porosity and creates a denser coating with improved corrosion resistance while maintaining manufacturability.
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 iron-based alloy coating achieves high bonding strength and significantly improved corrosion resistance, replacing conventional crystalline coatings with a densified and uniform structure, reducing porosity and maintaining amorphous structure post-laser re-melting.
Implementation Method 1
thermal sprays the iron-based alloy powder to form an amorphous iron-based alloy coating
Implementation Method 2
re-melts the iron-based alloy coating by a laser beam, such that the coating is densified and remains amorphous
Data Source
AI summary
A method of manufacturing an iron-based alloy coating is provided, which includes (a) providing an iron-based alloy powder having a chemical formula of FeaCrbMocSidBeYf, wherein 48≤a≤50; 21≤b≤23; 18≤c≤20; 2≤d≤3; 2≤e≤4; and 0<f≤2. The method also includes step (b) thermal spraying the iron-based alloy powder to form an amorphous iron-based alloy coating, and step (c) laser re-melting the amorphous iron-based alloy coating, wherein the iron-based alloy coating is densified and remains amorphous.