Differences Between PTFE and DLC (Diamond-Like Carbon) Coatings for Linear Motor Screws
In the fields of surface engineering and materials science, PTFE (polytetrafluoroethylene) coatings and Diamond-Like Carbon (DLC) coatings are two widely used technologies with distinct performance characteristics. Both coatings are available as customization options for our linear motor screws. Their unique physical and chemical properties make them suitable for diverse applications, ranging from everyday consumer goods to high-end precision equipment.
- Coefficient of Dry Friction (Unlubricated)
- PTFE coating: 0.03–0.10
- DLC coating: 0.05–0.15
- Coefficient of Friction Under Lubricated Conditions
- PTFE coating: 0.02–0.06
- DLC coating: 0.03–0.08
- Service Life and Durability
- PTFE coating:
The wear life of a PTFE-coated stainless steel screw varies significantly depending on actual operating conditions, ranging from several hundred to tens of thousands of hours. Under ideal conditions (dry friction, light load, low speed, no dust or impurities, and pairing with soft materials), the lifespan can reach several thousand to around ten thousand hours. In harsh conditions involving high loads, high speeds, erosion by hard particles, or pairing with high-hardness materials like hardened steel, the coating may wear or peel within a few hundred hours. Coating thickness (typically 5–50 μm) and application processes also directly influence its lifespan. PTFE coatings offer certain wear resistance, leaning more toward "low-friction wear resistance," which differs from the wear-resistant mechanisms of hard coatings such as chrome plating or nitriding.
- DLC coating:
The service life of DLC coatings far exceeds that of PTFE. Under high-load, standard industrial conditions, DLC lasts 5–10 times longer than PTFE. In severe scenarios with high loads and abrasive particle wear, where PTFE may peel within a few hundred hours, DLC can operate stably for several thousand to tens of thousands of hours. Its wear resistance is 10–50 times that of ordinary steel, whereas PTFE only offers 2–3 times the wear resistance of the base material.
- Core Advantages and Application Orientation
- PTFE coating:
Its core advantage lies in its extremely low coefficient of friction, which significantly reduces adhesion and friction loss during screw movement. It performs well in dry friction, light-load, and low-speed conditions. However, due to its lower hardness, it is prone to scratching and peeling in high-load, high-speed, or abrasive environments, leading to a notable decline in wear life.
- DLC coating:
DLC coatings feature high hardness (HV 4000–8000), a maximum operating temperature of 400°C, a coefficient of friction of 0.05–0.1, and strong adhesion, making them suitable for high-load, high-speed screw applications. In contrast, PTFE has a hardness of only HV 2–5 and a temperature resistance limit of 260°C. While its friction coefficient is slightly lower (0.03–0.1), it is prone to wear under high loads and has weaker adhesion, limiting its suitability to light-load, low-speed scenarios.
- General Notes and Selection Considerations
- PTFE coatings exhibit lower friction coefficients when paired with soft materials but may see an increase under high loads.
- DLC coatings offer high hardness and stable friction coefficients, with minimal impact from load variations.
- DLC coatings are recommended for stainless steel screws in precision transmission systems and heavy-duty equipment where high performance is required.
- PTFE coatings are better suited for simple transmission applications involving light loads, anti-adhesion needs, and low-speed conditions.
Updated on: 30/01/2026
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