Metal Carbide Protective Coating for Thin Corrosion-Resistant Parts
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Solution Overview
Problem
Existing methods for manufacturing protective coatings on metal substrates using hexavalent chromium are harmful to health and the environment, and there is a need to reduce manufacturing costs and improve corrosion resistance, especially for coatings of small thicknesses.
Innovation Solution
A method involving a surface preparation step followed by HVOF spraying of submicron metal carbide grains, impregnation with an organic impregnant, and polishing to form a compact protective layer, eliminating the need for sandblasting and reducing coating thickness while enhancing corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hexavalent chromium coating is applied to protect the substrate, then corrosion resistance is improved, but health and environmental safety deteriorates
Solution Approach 1:
The patent removes hexavalent chromium from the coating process entirely, extracting the harmful substance from the system while maintaining protective functionality through alternative materials and methods
Solution Approach 2:
The invention changes the chemical composition parameters by using alternative coating materials and processes that do not involve hexavalent chromium, thereby eliminating toxicity while preserving corrosion protection
2Reliability
If sandblasting is used to prepare the substrate surface, then adhesion of coating is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent removes the sandblasting step from the manufacturing process, extracting this complex operation while maintaining adhesion through direct application of the new coating method on simpler prepared surfaces
Solution Approach 2:
The invention replaces the mechanical sandblasting process with a different surface preparation approach that achieves adequate adhesion without the complexity of abrasive blasting equipment and procedures
3Quantity of substance
If coating thickness is reduced to lower manufacturing cost, then material consumption is decreased, but corrosion resistance deteriorates
Solution Approach 1:
The patent changes the chemical and physical parameters of the coating materials and application process to achieve superior corrosion resistance at reduced thickness, utilizing advanced material composition and improved deposition techniques
4Ease of manufacture
If traditional coating methods are used, then manufacturing cost is maintained, but corrosion resistance and reliability deteriorate
Solution Approach 1:
The invention optimizes multiple parameters including coating thickness, material composition, and application conditions to achieve better performance at lower cost by reducing material consumption while improving effectiveness
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 method achieves improved corrosion resistance and reduced manufacturing costs by forming a compact protective layer that is less prone to delamination, with equivalent or better performance compared to traditional methods, and reduces the risk of premature corrosion.
Implementation Method 1
forming, by spraying a powdery mixture containing submicron metal carbide grains according to a HVOF type spraying method, onto the prepared surface of the substrate, a coating layer
Implementation Method 2
a step of impregnating the coating layer with an organic impregnant together forming an impregnated layer
Implementation Method 3
the organic impregnant will enter the pores of the coating layer, fill them and thus form a more compact protective layer
Implementation Method 4
a step of polishing finishing at least one surface of said impregnated layer so as to form the protective layer comprising a polished surface having a roughness Ra of less than 0.2 μm
Data Source
AI summary
A method for manufacturing a part includes a metal substrate at least partially covered with a protective layer, includes preparing a surface of the substrate to be covered, forming by spraying, according to an HVOF spraying method, a coating layer on the prepared surface, this coating layer being formed by spraying a powder mixture containing submicronic metal carbide grains, impregnating the coating layer with an organic impregnant together forming an impregnated layer, finishing by polishing at least one surface of the impregnated layer in order to form a protective layer having a polished surface having a roughness Ra of less than 0.2 μm or of less than 0.1 μm depending on the applications.