Oxide Coating Structure for Compressor Slide Wear Resistance
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Solution Overview
Problem
Conventional oxide coating films on slide members in refrigerant compressors, such as phosphate coatings, experience reduced abrasion resistance and conformability due to the use of lower viscosity lubricating oils and shorter slide lengths, leading to increased friction and potential abnormal abrasion in harsh environments.
Innovation Solution
An oxide coating film with a specific configuration, including a silicon-containing portion closer to the base material and a diiron trioxide or triiron tetraoxide outermost surface, is applied to enhance adhesivity and abrasion resistance, comprising layers like diiron trioxide, triiron tetraoxide, and iron oxide, which improves the film's durability and conformability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional oxide coating films (phosphate coatings) are used on slide members, then initial conformability and surface finish are improved, but abrasion resistance deteriorates under harsh conditions (lower viscosity lubricating oils and shorter slide lengths)
Solution Approach 1:
The invention applies a composite oxide coating film comprising multiple layers with different compositions and functions: an inner layer containing FeO and Fe3O4 for adhesion, an intermediate layer with Fe3O4 and Fe2O3 for mechanical strength, and an outer layer with Fe2O3 and SiO2 for abrasion resistance. This multi-layer composite structure resolves the contradiction by combining the conformability benefits of conventional coatings with enhanced durability for harsh operating conditions.
Solution Approach 2:
The coating film is designed with spatially varying composition and properties: the inner layer near the base material provides strong adhesion, the intermediate layer provides mechanical strength and transition, and the outer layer provides abrasion resistance and chemical stability. This local differentiation of properties allows the single coating to simultaneously satisfy multiple conflicting requirements.
2Loss of energy
If lower viscosity lubricating oils are used to improve efficiency, then energy loss is reduced, but abrasion resistance of slide members deteriorates due to increased friction and wear
Solution Approach 1:
The invention replaces reliance on lubricating oil viscosity for friction control with a mechanically robust oxide coating film that provides inherent wear resistance. The multi-layer oxide structure creates a protective barrier that reduces direct metal-to-metal contact, allowing the system to use lower viscosity oils for energy efficiency while maintaining adequate abrasion resistance through the coating's mechanical properties.
3Productivity
If shorter slide lengths are designed to reduce device size, then productivity is improved, but conformability and abrasion resistance of slide members deteriorate
Solution Approach 1:
The invention changes the chemical composition parameters of the coating film by incorporating silicon-containing compounds and controlling the oxidation process to create a multi-layer structure with enhanced mechanical properties. This allows the coating to maintain conformability on shorter, more compact slide surfaces while providing the necessary abrasion resistance that would be difficult to achieve on smaller geometries.
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 enhanced oxide coating film provides improved abrasion resistance and reliability of slide members, reducing wear and maintaining conformability even under harsh conditions, thus increasing the durability and efficiency of refrigerant compressors.
Implementation Method 1
an oxide coating film which is provided on a surface of an iron-based material
Data Source
Figure 1
Figure 2A~2D
Figure 3
AI summary
An oxide coating film provided on a surface of an iron-based material which is a base material of a slide member has one of the following configurations: (1) the oxide coating film comprising a portion containing diiron trioxide (Fe2O3), in a region which is closer to an outermost surface of the oxide coating film; and a silicon containing portion containing silicon (Si) which is more in quantity than silicon (Si) of the base material, in a region which is closer to the base material, (2) the oxide coating film comprising: a composition A portion containing diiron trioxide (Fe2O3) which is more in quantity than other substances; a composition B portion containing triiron tetraoxide (Fe3O4) which is more in quantity than other substances and containing a silicon (Si) compound; and a composition C portion containing triiron tetraoxide (Fe3O4) which is more in quantity than other substances and containing silicon (Si) which is more in quantity than silicon (Si) of the composition B portion, and (3) the oxide coating film comprising: a first portion containing at least fine crystals; a second portion containing columnar grains, and/or a third portion containing layered grains.