For hard-working packaging knives and other industrial blades, the right coatings can boost performance, increase durability, and improve safety. This guide will review several coating treatments used to help machine knives cut cleaner, wear longer, and shrug off corrosion. Read on to learn which industrial blade coating can give you the edge you need.
Common Industrial Blade Coatings
From tried and true metal plating options to high-tech vapor-deposited and powdered options, blade coatings improve the natural qualities of knife-making metals and alloys to extend and enhance cutting performance.
Titanium nitride (TiN) is by far the most widely used coating for industrial blades. Its ability to increase significantly both surface hardness and wear resistance makes it a game changer for machine knife manufacturers.
TiN also comes with a lower coefficient of friction, allowing treated blades to cut more cleanly. This is valuable for high-heat applications in the packaging and converting industries, where melted plastic or sealant can build up on blades. It’s also particularly useful for processing many foodstuffs, especially since TiN is approved for food handling by the FDA,
TiN is a ceramic coating usually applied using a physical vapor deposition process, which involves vaporizing titanium in an inert atmosphere and then depositing it electrostatically on the blade surface in a single u1.5-micron layer.
The additional hardness of TiN-coated blades (about three times that of conventional chrome plating) allows knives with complex edge shapes—including slotted, teethed, and scalloped blades that usually need to be made using softer alloys such as spring steel—to be deployed in demanding environments requiring hardness up to 85 on the Rockwell C (RC) hardness scale.
TiN is widely used for packaging bagger knives, while its FDA-approved low-adhesion qualities make it ideal for many food-handling applications.
Titanium carbo-nitride (TiCN) offers hardness approaching that provided by TiN, but with both increased abrasion resistance and a lower friction coefficient.
TiCN coatings provide up to 80RC hardness for treated blades but with more wear resistance than traditional TiN coatings. This means TiCN knives can offer significantly longer wear along with only a small decrease in hardness while also offering greater resistance to chipping, flaking, or blistering than TiN coatings.
TiCN is applied through a chemical deposition process, meaning it becomes chemically bonded with carbon atoms in the surface of the blade in a layer about 3 micrometers thick during the vapor deposition process. A well-made TiCN tool can last between 3 to 10 times as long as many uncoated alloy blades.
Blades with TiCN coating offer all the same advantages as TiN blades, allowing hard-wearing knives with comparable or only slightly lower hardness to be made from pliable alloys. Its low friction, stability, and non-stick qualities make it ideal for a wide range of demanding industrial, packaging, and food-handling applications.
TiCN coatings are FDA approved and are also used for surgical tools and devices.
Diamond-like carbon (DLC) coatings allow industrial blades to be made with hardnesses surpassing that of many titanium-based finishes, with superior friction and wear characteristics for the most demanding applications.
Applied via a plasma-enhanced chemical vapor deposition process, these coatings involve fusing a layer of densely-packed carbon molecules to the surface of the blade, giving it a distinctive black color. DLC can be applied to a wide range of alloys including:
- High-speed steels
- Tool steels
- Carbon steels
- Stainless steels
- Carbide materials
Tightly-packed carbon molecules give DLC coatings hardnesses up to 80 RC while also improving abrasion resistance, which allows for low-friction clean cuts.
DLC-treated blades are used in heavy industry to manufacture brake surfaces and engine seal, among many other things. Their clean-cutting characteristics and natural resistance to corrosion make them a great choice for demanding food-handling jobs like at-sea processing. They are often used to coat packaging bagging knives used to separate blown film and composites.
Teflon is a brand name for polytetrafluoroethylene (PFTE), a non-stick coating originally developed by Du Pont. Teflon and similar PTFE coatings for different applications are now provided by vendors across the United States.
A polymer combining carbon and fluorine, PFTE is hydrophobic, giving it low adhesion properties. It also boasts an extremely low friction coefficient. This gives PTFE-coated blades non-stick and clean-cutting properties that are ideal for food handling, preventing food build-up, and enhancing knife durability. Teflon is also FDA-approved for food handling applications.
While it’s incredibly strong, PFTE is a polymer coating and therefore is potentially vulnerable to chipping. Conventional PFTE formulations also match the hardnesses offered by titanium-based and carbon-based coatings.
In addition to direct food handling applications, PFTE is used to coat industrial packaging knives including bar slitters and roll scraper blades.
Chrome plating involves adding a layer of chrome molecules to the surface of a metal through electroplating. Like titanium-based coatings, chrome plating improves the surface hardness of metals. This allows more pliable metals to be hardened for use in more demanding applications.
Chrome plating offers increased corrosion resistance as well as easier cleaning. Depending on the thickness of the chrome applied, chrome plated blades can deliver hardnesses between 66 and 70 RC. While this is significantly lower than TiN, TiCN, and DLC coatings—chrome plating is also cheaper than these processes.
While increased hardness may help increase the lifespan of a blade, chrome plating is also relatively vulnerable to high abrasion forces that can potentially strip the chrome coating from the underlying surface, eventually reducing durability.
The attractive appearance of chrome makes it a popular choice for consumer knives. For industrial blades, chrome is most often used to coat high-speed carbon steels. These are used in straight knives and other blades designed for high-speed, high-heat applications like packaging slitting and sealing.
Similar to chrome, coating industrial blades with a layer of nickel through electroplating offers increased hardness while improving resistance to corrosion.
Nickel-coating a metal can offer hardnesses of between 58 and 62 RC, which is lower than chrome plating as well as titanium-based and carbon-based coatings. Cheaper than chrome, nickel protects blades and makes them easier to clean. This natural resistance to sticking also makes nickel-coated knives suitable for food-handling applications.
Nickel coatings are also more vulnerable to scratches and abrasions, but offer reasonable resistance to wear and improved performance over softer spring or low carbon steels as long as the coating remains intact.
Nickel oxide powders can be spray coated onto blade surfaces to provide increased corrosion resistance and reduced friction. This is useful for blades that will be exposed to very corrosive briny environments, such as seafood processing at sea. Overall wear resistance is also improved compared to many milder steels.
Spray-applied nickel dioxide coating is preferred to electroplating in some applications because it’s easier to control the thickness of the layer of nickel that is deposited across the target surface.
Nickel-based coatings perform well where clean-cutting, non-stick, and corrosion resistance properties are required, but extreme hardness is not. They can offer a cost-effective solution for many high-volume food handling applications and outperform in settings where cleanliness and corrosion resistance are essential.
The performance of spray-application nickel powders can also be leveraged by combining them with other metals—such as titanium—to deliver the benefits of both substances.
The Right Coating for Your Application
TGW International is a quality-first industrial knife manufacturer known for the craftsmanship and precision of our blades. With more than 100 years of experience, we can match specialty blades to any process.
Whatever your plastic packaging application is, TGW can supply custom and replacement knives that meet or exceed OEM specifications. We work closely with you to find solutions to your production challenges. In many cases, performance and durability can be enhanced by:
- Upgrading the base material
- Applying a wear or anti-corrosion coating
TGW packages blades that are designed specifically to meet most horizontal and vertical packaging applications and can be supplied TiN, TiCN, DLC, and other proven coatings to deliver quality, longevity, and savings.
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