Tablet Punch Coatings: Chrome vs DLC vs TiN vs CrN Compared

Tablet punch coatings solve specific production problems — sticking, wear, and corrosion. But with multiple coating options available, choosing the right one for your application can be confusing. This guide compares the four most common tablet punch coatings, explains when to use each, and helps you make a cost-effective decision.

Why Coat Tablet Punches?

Uncoated steel punches work well for many formulations. But certain formulations cause problems that coatings can solve:

If your current uncoated tooling performs well without these issues, coatings are unnecessary. Coatings add cost — use them to solve specific problems, not as a default specification.

Chrome Plating — The Standard Coating

Chrome plating (hard chromium electroplating) is the most widely used and most affordable tablet punch coating.

Properties:

• Hardness: 800-1000 HV (Vickers)

• Thickness: 5-15 μm

• Application method: Electroplating

• Color: Bright silver/mirror finish

Benefits:

• Reduced sticking — smooth chrome surface reduces material adhesion

• Corrosion protection — chrome layer protects steel from moisture and acidic formulations

• Improved surface finish — chrome provides a mirror-like surface

• Low cost — most affordable coating option

• Easy to reapply — can be stripped and replated when worn

Limitations:

• Moderate wear resistance — not as hard as TiN or DLC

• Can chip or peel if poorly applied

• Not effective for severely sticky formulations (DLC is better)

• Environmental concerns with hexavalent chromium plating processes

Best For:

• General-purpose corrosion protection

• Moderate sticking problems

• Budget-conscious applications

• Standard pharmaceutical and nutraceutical tooling

DLC (Diamond-Like Carbon) — Premium Anti-Stick

DLC coating is a thin carbon-based film with properties similar to diamond. It is the gold standard for preventing tablet sticking and picking

Properties:

• Hardness: 2000-5000 HV (Vickers) — significantly harder than chrome

• Thickness: 1-3 μm

• Color: Dark gray to black

• Application method: Physical Vapor Deposition (PVD)

• Friction coefficient: 0.05-0.15 (extremely low)

Benefits:

• Excellent anti-stick properties — the lowest friction coefficient of any common coating

• Solves severe sticking problems that chrome cannot

• Very hard surface — resists wear and scratching

• Chemically inert — does not react with formulation ingredients

• Thin coating — does not change punch dimensions significantly

Limitations:

• Higher cost — 3-5x more expensive than chrome plating

• Cannot be reapplied easily — requires stripping and recoating

• Brittle under extreme impact — not ideal for very high compression forces

• Dark color may be a concern for visual inspection (harder to see residue)

Best For:

• Severely sticky formulations (herbal extracts, hygroscopic ingredients)

• Ayurvedic and herbal tablet manufacturing

• Embossed punches where picking is a problem

• High-value products where sticking causes significant waste

TiN (Titanium Nitride) — Wear Resistance Champion

TiN coating is a hard ceramic coating that dramatically extends punch tip life when processing abrasive formulations.

Properties:

• Hardness: 2000-2500 HV (Vickers)

• Thickness: 2-5 μm

• Color: Gold/yellow

• Application method: Physical Vapor Deposition (PVD)

Benefits:

• Excellent wear resistance — extends tooling life by 30-50% or more

• Hard surface resists abrasion from calcium, iron, and mineral ingredients

• Good chemical stability — resists most formulation ingredients

• Distinctive gold color makes it easy to identify coated tooling

• Maintains sharp embossing detail longer than uncoated tooling

Limitations:

• Moderate anti-stick properties — not as effective as DLC for sticking

• Higher cost than chrome (but lower than DLC)

• Cannot be easily reapplied

• May not be suitable for all formulation colors (gold color transfer risk is minimal but exists)

Best For:

• High-volume production where tooling wear is the primary concern

• Nutraceutical tablets with mineral ingredients

• Any application where extending tooling life is the priority

• Abrasive formulations containing calcium, iron, or mineral compounds

CrN (Chromium Nitride) — Dual Protection

CrN coating provides both corrosion resistance and wear resistance — a combination that neither chrome plating nor TiN alone can match.

Properties:

• Hardness: 1800-2200 HV (Vickers)

• Thickness: 2-5 μm

• Color: Silver-gray

• Application method: Physical Vapor Deposition (PVD)

Benefits:

• Excellent corrosion resistance — superior to chrome plating

• Good wear resistance — better than chrome, comparable to TiN

• Dual protection — handles both corrosive and abrasive formulations

• Good thermal stability — maintains properties at elevated temperatures

• Silver-gray color blends with steel appearance

Limitations:

• Higher cost than chrome plating

• Anti-stick properties are moderate (DLC is better for sticking)

• Less widely available than chrome or TiN

Best For:

• Corrosive formulations (acidic, effervescent)

• Formulations that are both corrosive and abrasive

• Environments with high humidity or corrosion risk

Head-to-Head Comparison

Key insight: For abrasive formulations, coated tooling costs more per set but requires fewer replacements per year. The annual tooling cost is actually lower with coatings. For non-abrasive formulations, the savings are smaller and may not justify the coating cost.

Coating Care and Maintenance

Coated tooling requires the same maintenance as uncoated tooling, with a few additional considerations:

• Do not use abrasive cleaning methods — steel wool and abrasive pads damage coatings

• Use soft cloths and mild solvents for cleaning

• Do not attempt to polish coated tips — polishing removes the coating

• Inspect coating integrity — look for peeling, chipping, or wear-through

• Replace when coating is worn through — exposed steel underneath will corrode and stick

Decision Guide — Which Coating Do You Need?

Use this flowchart:

1. Is sticking/picking your main problem?

• Yes → DLC (severe sticking) or Chrome (moderate sticking)

• No → Continue

2. Is rapid wear from abrasive ingredients your main problem?

• Yes → TiN

• No → Continue

3. Is corrosion from acidic/corrosive formulations your main problem?

• Yes → CrN (if also abrasive) or Chrome (corrosion only)

• No → Continue

4. Do you have multiple problems (sticking + wear + corrosion)?

• Sticking + wear → DLC

• Corrosion + wear → CrN

• All three → DLC on tips + EMMKAY Special Steel base material

5. No specific problems?: No coating needed — save the cost

Cost-Benefit Analysis

Conclusion

The right coating depends on your specific problem. DLC for sticking, TiN for wear, CrN for corrosion, and chrome for general protection. If you have no specific problems, save the cost and use uncoated tooling.

EMMKAY INDUSTRIES offers all four coating options on our tablet dies and punches. Contact us to discuss which coating is right for your formulation.