Ti-C-Ti-C Coating for Copper Corrosion Resistance
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Solution Overview
Problem
Copper components in electronic devices and other manufactured goods are prone to corrosion due to reaction with oxygen, with diamond-like carbon (DLC) films providing inadequate protection, resulting in higher corrosion rates compared to other metals like NiFe substrates.
Innovation Solution
A protective coating comprising alternating layers of titanium ions and carbon, forming a Ti—C—Ti—C structure, which is deposited using filtered cathodic arc deposition, providing a robust barrier against corrosion on copper substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thin film of diamond like carbon (DLC) is applied to copper substrate, then the copper surface is protected from corrosion initially, but the corrosion rate is 1 to 2 orders of magnitude higher than on NiFe substrates, resulting in inadequate long-term protection
Solution Approach 1:
The coating is segmented into multiple alternating layers of titanium ions and carbon (Ti-C-Ti-C structure), creating a multi-layered protective system. This segmentation allows each layer to contribute differently to corrosion resistance, with titanium providing barrier protection and carbon providing surface stability, achieving superior long-term durability compared to single-layer DLC coatings
Solution Approach 2:
The invention uses a composite coating structure combining titanium ions and carbon in alternating layers. This composite material approach leverages the complementary properties of both materials: titanium's corrosion barrier characteristics and carbon's surface stability, resulting in a coating that reduces corrosion rates to levels comparable to NiFe substrates
2Adaptability or versatility
If copper surfaces are exposed to oxygen in air bearing surfaces, then the copper component can be used in disc drives, but corrosion occurs leading to copper oxide formation and DLC film delamination
Solution Approach 1:
The titanium-containing coating is applied in advance to copper surfaces before they are exposed to oxygen-containing environments. This preliminary protective layer prevents copper oxide formation and eliminates the harmful effects of corrosion, allowing copper components to be used in oxygen-exposed applications like disc drive air bearing surfaces without degradation
Solution Approach 2:
The coating system converts the naturally reactive properties of copper, which normally lead to corrosion, into an advantage by creating a stable titanium-carbon interface that actually enhances corrosion resistance. The titanium layers react with oxygen instead of copper, forming a protective barrier that benefits the overall system
3Ease of operation
If corrosion occurs on copper surfaces in devices with very small physical clearances, then the device functionality is compromised due to physical interference, magnetic interference, and electronic interference
Solution Approach 1:
The titanium-carbon coating system provides a pre-established protective cushion between the copper surface and the corrosive environment. This beforehand protection prevents copper oxide formation that would otherwise cause physical clearance issues, magnetic interference, and electronic interference in devices with very small tolerances
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 Ti—C—Ti—C coating significantly reduces corrosion rates on copper surfaces to levels comparable to NiFe substrates, enhancing the longevity of copper components and maintaining device functionality in tight clearances.
Implementation Method 1
which is deposited using filtered cathodic arc deposition
Data Source
AI summary
A protecting coating for a copper substrate is disclosed. The coating comprises seed layer comprising titanium ions that forms an “alloy-like” structure with the copper substrate. The coating further comprises a first layer of carbon disposed on the seed layer comprising titanium ions. A second layer comprising titanium is disposed on the first layer of carbon, and a second layer of carbon is disposed on the second layer comprising titanium.