Amorphous Fe-Cr-Mo Coating for Wear and Corrosion Resistance
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Solution Overview
Problem
Conventional ferrous and non-ferrous alloys used in heavy construction and machinery lack adequate resistance to wear, erosion, and corrosion, especially in aggressive environments, due to porosity and through-cracks in hard-facing materials applied by thermal spraying, which compromise the substrate's integrity.
Innovation Solution
A molybdenum-containing ferrous alloy with a composition of chromium, molybdenum, carbon, and iron, at least partially amorphous, is developed for improved thermal spray deposition, forming a coating with enhanced hard-facing properties and thermal conductivity, using a high-velocity thermal spraying process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional hard-facing materials are applied by thermal spraying, then wear resistance is improved, but porosity and through-cracks are introduced that compromise substrate integrity
Solution Approach 1:
The patent modifies the chemical composition parameters of the hard-facing alloy by incorporating specific elements (Cr: 22-28%, Mo: 14-20%, C: 2-3%, B: 1.5-2%) in optimized proportions. This compositional parameter change enables the material to achieve both high wear resistance and reduced porosity/through-cracks, thereby maintaining substrate integrity while providing protective functionality.
Solution Approach 2:
The patent creates a composite alloy system combining multiple metallic elements (Fe, Cr, Mo, C, B) with specific functional characteristics. The composite structure leverages the wear resistance of chromium carbide phases, the toughness of the iron matrix, and the grain-refining effect of boron to simultaneously improve wear resistance and reduce defects that compromise substrate integrity.
2Strength
If hard-facing material is deposited to protect against wear and corrosion, then protective layer strength is improved, but coating porosity increases allowing corrosive media to penetrate
Solution Approach 1:
The patent adjusts the chemical composition parameters to include chromium (22-28%) and boron (1.5-2%) in specific ranges that promote formation of a dense, low-porosity coating structure. These parameter changes enable the protective layer to achieve both strength and resistance to corrosive media penetration by reducing void spaces through optimized alloying.
Solution Approach 2:
The patent creates local quality variations within the coating structure through controlled alloying, where chromium-rich carbide phases form at grain boundaries and interfaces to provide localized reinforcement and sealing. This local quality enhancement reduces porosity at critical interfaces and prevents corrosive media penetration while maintaining overall coating strength.
3Productivity
If thermal spray deposition is used to apply hard-facing material, then deposition speed is improved, but coating quality deteriorates due to porosity and cracks
Solution Approach 1:
The patent modifies the material parameters (chemical composition with Cr: 22-28%, Mo: 14-20%, C: 2-3%, B: 1.5-2%) to enable faster cooling rates during thermal spray deposition. These parameter changes allow the coating to solidify quickly at high deposition speeds while forming a dense, high-quality microstructure with reduced porosity and cracks, thus maintaining both productivity and manufacturing precision.
Solution Approach 2:
The patent utilizes phase transition control during thermal spray deposition, where the alloyed powder melts and rapidly solidifies upon impact with the substrate. The specific composition (Fe-Cr-Mo-C-B system) enables controlled phase formation during this rapid cooling, creating a fine-grained, dense microstructure that forms quickly at high deposition rates while maintaining high coating quality with minimal defects.
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 molybdenum-containing alloy coating provides improved wear resistance, corrosion resistance, and thermal conductivity, reducing porosity and enhancing the durability of the substrate, while maintaining the structural integrity of the underlying material.
Implementation Method 1
a molybdenum-containing ferrous alloy with a composition of chromium, molybdenum, carbon, and iron, at least partially amorphous, is developed for improved thermal spray deposition
Implementation Method 2
forming a coating with enhanced hard-facing properties and thermal conductivity
Implementation Method 3
using a high-velocity thermal spraying process
Data Source
AI summary
One embodiment provides a composition, comprising: a powder composition comprising alloy that is at least partially amorphous, the alloy comprising chromium, molybdenum, carbon, boron, and iron. One embodiment provides a method of forming a coating, comprising: providing a substrate; and disposing onto the substrate a coating, comprising: powder composition comprising an alloy that is at least partially amorphous, the alloy comprising chromium, molybdenum, carbon, boron, and iron.