Vacuum Pump Components Free Conversion Layer
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Solution Overview
Problem
Conventional coatings for vacuum pump components made of valve metals and their alloys, such as anodization and electroless nickel layers, suffer from pore structures, 'pinholes', inadequate tribological behavior, and limited resistance to corrosion, heat, and chemical agents like citric acid and hydrochloric acid vapors, particularly in aggressive gas environments.
Innovation Solution
A galvanically produced coating of oxide and/or oxyfluorides of boron, germanium, aluminum, magnesium, titanium, niobium, hafnium, and zirconium, applied without a conversion layer, providing a contour-accurate, repeatable, and economically beneficial solution with reduced exposure times and enhanced abrasive wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional anodization or electroless nickel coating is applied to valve metal components, then corrosion protection is provided, but the coating contains pore structures or pinholes that limit protection against aggressive gases like HCl and HF vapors
Solution Approach 1:
The patent changes the chemical composition parameters of the coating by using oxyfluorides (particularly Al2O3, TiO2, ZrO2, and their mixtures) instead of conventional oxide or nickel coatings. This compositional change eliminates the pore structures and pinholes inherent in traditional coatings, creating a dense, impermeable barrier against aggressive gases like HCl and HF vapors while maintaining corrosion protection.
Solution Approach 2:
The patent employs composite coating systems consisting of multiple oxide and oxyfluoride layers (Al2O3, TiO2, ZrO2, and their combinations) applied in sequence. This multi-layer composite structure provides superior protection by combining the benefits of different materials - the density and chemical resistance of oxyfluorides with the protective properties of oxides, eliminating the defects of single-material conventional coatings.
2Reliability
If conversion layers are formed on valve metal surfaces, then surface protection is achieved, but substrate material is removed and converted, causing loss of material
Solution Approach 1:
Instead of removing and converting substrate material to form protective layers (as in anodization), the patent inverts the approach by applying protective oxyfluoride coatings through electrolytic deposition from solution. This preserves the intact substrate material while achieving surface protection, eliminating the material loss inherent in conversion layer formation.
Solution Approach 2:
The patent introduces an intermediary coating layer composed of oxyfluorides (Al2O3, TiO2, ZrO2) that serves as the protective barrier without requiring conversion of the substrate. This intermediary layer is deposited electrolytically from aqueous solutions containing the respective metal salts, providing protection while leaving the valve metal substrate intact and unconverted.
3Reliability
If conventional coatings are applied to vacuum pump components, then some protection is provided, but tribological behavior is insufficient and cold welding occurs in crashes
Solution Approach 1:
The patent changes the surface properties of the coating by using oxyfluoride materials (particularly Al2O3, TiO2, ZrO2) with inherently superior tribological characteristics. These materials provide low friction and wear properties that prevent cold welding during crashes, unlike conventional coatings such as electroless nickel that exhibit inadequate tribological behavior in vacuum environments.
4Reliability
If anodization processes are used to form protective layers, then coating is achieved, but the process takes considerable time and is expensive
Solution Approach 1:
The patent changes the electrolytic deposition parameters by using aqueous solutions of metal salts (alumium, titanium, zirconium salts) with controlled concentration and composition. This optimization enables rapid formation of dense oxyfluoride coatings with reduced exposure times compared to conventional anodization, while maintaining superior protection qualities.
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 solution offers superior corrosion protection, resistance to citric acid and hydrochloric acid, and extended service life, with no substrate material loss, and is more resistant to abrasive wear compared to traditional methods, ensuring reliable performance in harsh vacuum environments.
Implementation Method 1
a galvanically produced coating of at least one oxide and/or one oxyfluoride of an element from the group consisting of boron, germanium, aluminum, magnesium, titanium, niobium, hafnium and/or zirconium
Implementation Method 2
superior corrosion protection, resistance to citric acid and hydrochloric acid
Implementation Method 3
extended service life, with no substrate material loss, and is more resistant to abrasive wear compared to traditional methods
Data Source
AI summary
The invention relates to conversion coating-free components of vacuum pumps made of valve metals and the alloys thereof.