Diamond-Like Carbon (DLC) Coatings

Diamond-like carbon (DLC) coatings are increasingly used in various applications, including food processing equipment, due to their hardness, low friction, and biocompatibility. In the context of food safety, specific DLC coatings have been developed and approved for use in food contact applications. Here’s an overview of approved DLC coatings suitable for food use, including those that may be clear and transparent for coating optical sensors.

Approved DLC Coatings for Food Use

1. Tungsten Carbide DLC (WC-DLC)
   • Approval: Commonly used in food processing equipment, this coating provides wear resistance and corrosion protection.
   • Manufacturer: Companies like Sustainable Coatings and Tandem Diabetes have worked with WC-DLC coatings for medical and food applications.
2. Silicon-DLC Coatings (Si-DLC)
   • Approval: Si-DLC is known for its excellent hardness and wear resistance and is often used in food contact applications.
   • Manufacturer: Amedica Corporation produces Si-DLC coatings, which have applications in medical devices and food processing equipment.
3. Carbon-Nitride Coatings (CNx)
   • Approval: These coatings exhibit properties similar to DLC and are suitable for food contact applications due to their biocompatibility.
   • Manufacturer: Advanced Diamond Technologies, Inc. provides CNx coatings for various applications, including food processing.
4. Hydrogenated DLC (H-DLC)
   • Approval: This variant is often used in applications requiring flexibility and impact resistance, suitable for food contact.
   • Manufacturer: FHR Anlagenbau GmbH is known for H-DLC coatings that are compliant with food safety regulations.

Clear and Transparent DLC Coatings

While many DLC coatings are typically opaque or dark in color, some companies have developed clear and transparent DLC variants that may be suitable for optical applications.

1. Transparent DLC Coatings
   • Manufacturer: Nanovere Technologies offers transparent DLC coatings that can be used on various substrates, including metals and plastics, and may be suitable for optical sensors in food processing.
2. Diamond-Like Carbon (DLC) Thin Films
   • Manufacturer: Norton™ Diamond Coatings specializes in thin-film coatings, including transparent DLC options that can provide hardness and durability while maintaining optical clarity.

Considerations for Optical Sensors

• Adhesion: When selecting a DLC coating for optical sensors, ensure that the coating adheres well to the sensor material (often glass or plastic) to avoid peeling or delamination.
• Clarity and Transmission: The optical transparency of the DLC coating must be high enough to not interfere with the sensor’s performance, as any haze or distortion can impact readings.
• Compatibility: Check that the chosen DLC coating is certified for food contact and meets relevant regulations (e.g., FDA or EU food safety standards).

While several DLC coatings are approved for food contact applications, the availability of clear and transparent options for optical sensors is more limited. Manufacturers like Nanovere Technologies and Norton™ Diamond Coatings are potential sources for these specialized coatings. Always verify specific compliance with food safety standards and optical performance requirements when selecting a coating for use in dairy or food processing environments.