Wear-Resistant Titanium Member with Carburized and GLC Layers
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Solution Overview
Problem
Titanium alloys used in fastening and sliding members face challenges in achieving sufficient wear resistance under severe sliding wear conditions when in contact with carbon fiber reinforced plastics, due to the difficulty in combining plasma carburizing and titanium oxide treatments without compromising mechanical strength or increasing costs.
Innovation Solution
A wear-resistant titanium metal member is created with a carburized layer having a polished surface roughness of 0.01 to 0.80 μm, a titanium oxide layer, and an amorphous carbon layer formed through specific plasma carburizing and heat treatment processes, allowing for improved wear resistance and reduced stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dense titanium oxide film is formed on the surface of titanium metal to improve corrosion resistance and wear resistance, then the titanium oxide film makes it easier to form an amorphous carbon layer on the surface, but this film prevents penetration of activated carbon ions into the titanium metal (carburization) and makes it difficult to form a carburized layer under the amorphous carbon layer
Solution Approach 1:
The patent applies preliminary action by forming a titanium oxide film on the surface of titanium metal before subjecting it to plasma carburizing treatment. This pre-formed oxide film serves as a foundation that facilitates subsequent amorphous carbon layer formation while the patent subsequently removes or modifies this film to enable carbon ion penetration and carburization, thereby resolving the contradiction between corrosion resistance and carburization ease.
2Reliability
If plasma carburizing treatment is performed on titanium metal to improve wear resistance, then a hard layer of metal carbide is formed on the surface, but the surface must be polished to a mirror finish to form a good-quality amorphous carbon layer thereafter, which is technically difficult, costly, and inefficient
Solution Approach 1:
The patent applies the taking out principle by removing the requirement for mirror finish polishing after plasma carburizing. Instead of insisting on a perfectly smooth surface, the patent extracts the essential function (wear resistance) and achieves it through alternative means that do not require costly and time-consuming mirror polishing, thereby simplifying the manufacturing process while maintaining wear resistance.
Solution Approach 2:
The patent applies parameter changes by modifying the surface roughness parameters after plasma carburizing. Rather than requiring mirror finish (Ra ≈ 0), the patent accepts and utilizes a controlled surface roughness range (Ra 0.01-0.80 μm) that still enables formation of high-quality amorphous carbon layers, thereby eliminating the need for extensive polishing while maintaining wear resistance.
3Manufacturing precision
If the surface of titanium metal is polished to a mirror finish to enable formation of a good-quality amorphous carbon layer, then the amorphous carbon layer can be formed, but the process becomes technically difficult, costly, and inefficient
Solution Approach 1:
The patent applies parameter changes by redefining the acceptable surface roughness range from mirror finish (Ra ≈ 0) to a broader range (Ra 0.01-0.80 μm). This parameter change maintains sufficient surface smoothness for high-quality amorphous carbon layer formation while dramatically improving manufacturing efficiency by eliminating the need for extensive mirror polishing operations.
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 enhances the wear resistance of titanium metal members to withstand harsh sliding conditions with carbon fiber reinforced plastics, maintaining high mechanical strength and preventing damage to both the titanium and carbon fiber reinforced plastic components.
Implementation Method 1
a carburized layer formed by plasma carburizing
Implementation Method 2
accelerated activated carbon ions collide against and stick to the surface of the titanium metal, and then diffuse into the titanium metal thereafter
Implementation Method 3
a titanium oxide layer formed by oxidizing the polished surface
Implementation Method 4
subject the surface of the titanium oxide to plasma heat treatment in an atmosphere containing a hydrocarbon gas and kept at 0.1 to 30 torr and 400 to 1100° C., thereby efficiently forming a high-quality glass-like carbon film
Data Source
AI summary
A wear-resistant titanium metal member includes a substrate having a carburized layer formed by plasma carburizing and a polished surface having a surface roughness Ra of 0.01 to 0.80 μm formed on the surface of the carburized layer, a titanium oxide layer superposed on the polished surface, and an amorphous carbon (GLC) layer superposed on the titanium oxide layer. The GLC layer is rigid and has a flat and smooth surface, so that it is free of stress concentration. By adjusting the plasma carburizing temperature and the concentration of the carburizing gas, carbon ions can penetrate the polished surface and form the carburized layer under the polished surface.