Corrosion-Resistant Roller Coating via Thermal Spray and Polymer Sealing
Solution Overview
Problem
Current corrosion protection methods for paper machine rolls, such as galvanic hard chrome plating, are environmentally harmful and costly, while thermal hard metal coatings are expensive and difficult to clean, necessitating a cost-effective and environmentally friendly alternative.
Innovation Solution
A thermal spray coating method using stainless steel materials, specifically chrome-nickel-steel, applied in dense layers with low porosity, followed by a polymer sealing layer to prevent corrosion from electrolytes, utilizing high velocity flame or arc spraying techniques, and optionally enhanced with carbides or nitrides for increased durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If galvanic hard chrome plating is used for corrosion protection, then effective corrosion protection is achieved at low cost, but environmental pollution increases due to toxic electroplating baths
Solution Approach 1:
The invention changes the manufacturing process parameters by replacing galvanic electroplating with thermal spray coating followed by polymer sealing. This process substitution eliminates toxic electroplating baths while achieving comparable corrosion protection, thereby reducing environmental pollution while maintaining cost effectiveness.
Solution Approach 2:
The invention uses a composite coating system consisting of thermal spray applied metal or ceramic layers combined with a polymer sealing layer. This composite approach provides effective corrosion protection similar to galvanic chrome plating but without the environmental harm, as the thermal spray process and polymer sealing are environmentally friendly alternatives to toxic electroplating.
2Object-affected harmful factors
If thermal hard metal spray coating is used for corrosion protection, then environmental compatibility is improved, but manufacturing cost increases significantly
Solution Approach 1:
The invention segments the corrosion protection function into two parts: a thermal spray applied metal or ceramic layer for base protection, and a polymer sealing layer for enhanced corrosion resistance. This segmentation allows the use of more economical materials and processes compared to full thermal hard metal coating, thereby reducing manufacturing cost while maintaining environmental compatibility.
Solution Approach 2:
The polymer sealing layer acts as an intermediary that enhances the corrosion resistance of the thermal spray coating. This intermediary layer allows the use of less expensive base materials while achieving the same level of environmental compatibility and corrosion protection as expensive thermal hard metal coatings.
3Ease of manufacture
If galvanic hard chrome plating is used on guide rolls, then cost effectiveness is improved, but cleaning ability deteriorates as the coating cannot be doctored
Solution Approach 1:
The invention applies different properties to different parts of the coating system: the thermal spray layer provides corrosion protection, while the polymer sealing layer provides a smooth, doctorable surface for easy cleaning. This local quality differentiation allows the coating to be both cost-effective and easily maintainable, resolving the contradiction between cost effectiveness and cleaning ability.
4Ease of manufacture
If thermal spray coating with stainless steel is used, then manufacturing cost is reduced, but corrosion resistance may be insufficient without additional sealing
Solution Approach 1:
The invention uses a composite coating system where a thermal spray applied stainless steel or other metal/ceramic layer is combined with a polymer sealing layer. The thermal spray layer provides base corrosion protection at low cost, while the polymer sealing layer enhances corrosion resistance, thereby achieving both cost reduction and reliable corrosion protection.
Solution Approach 2:
The polymer sealing layer serves as a beforehand cushion that protects the thermal spray coating from corrosive attack. This pre-applied protective layer prevents electrolytes from reaching and degrading the thermal spray coating, thereby maintaining corrosion resistance reliability while keeping manufacturing costs low.
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 provides a cost-effective, environmentally friendly corrosion protection for paper machine rolls, ensuring effective prevention of corrosion and easy cleaning, with dense, low-porosity coatings that maintain integrity under operational conditions.
Implementation Method 1
coating of at least part of the surface of the roll component by applying a stainless steel material using the device for thermal spray coating
Implementation Method 2
the provided device for thermal spray coating is configured for implementation of high velocity flame spraying or laser spraying
Implementation Method 3
the provided device for thermal spray coating is configured for implementation of arc spraying
Implementation Method 4
sealing of the stainless steel spray coating with a polymer prevents an attack by electrolytes on defective areas of the coating material, thereby effectively preventing corrosion of the spray coating and advancing of the corrosion causing electrolytes to the base material
Data Source
AI summary
A method for applying a corrosion-protective coating to a roller component includes the steps of providing a device for thermal spray coating, providing a stainless steel material, coating at least one part of the surface of the roller component by applying the stainless steel material using the device for thermal spray coating and sealing the applied coating by a polymer material.