I. Core Principles

Wear resistance depends on coating materials with high hardness, low friction, and oxidation resistance; chip resistance depends on coating toughness, bond strength between the coating and substrate, stress matching, and multilayer structures, which prevent coating cracking, peeling, and chipping.

II. Selection of Common Coatings (Directly Corresponding to Performance)

Prioritize wear resistance: TiN, TiCN, AlTiN, Si-based coatings

High hardness, resistance to high-temperature oxidation, and reduced cutting friction and wear; suitable for high-speed machining of steel and cast iron.

Chip-Resistance Priority: Nano-multilayer coatings, gradient coatings, TiSiN, AlCrN

Good toughness, low internal stress, and the ability to absorb impact; suitable for intermittent cutting, heavy-duty cutting, and stainless steel/high-temperature alloys.

Balancing Wear Resistance and Chipping Resistance: Multi-layer Composite Coatings (TiN base layer + TiCN intermediate layer + AlTiN top layer)

The base layer enhances adhesion, the intermediate layer provides impact resistance, and the top layer offers high-temperature wear resistance.

III. Process-Level Improvement Methods

Pre-treatment Enhancement

Deburring, polishing, and cobalt removal of the cemented carbide substrate improve coating-substrate adhesion and prevent coating delamination and chipping.

Optimizing Coating Thickness

Excessively thick coatings are prone to brittle chipping, while excessively thin ones lack wear resistance; standard milling cutters require 3–8 μm, heavy-duty cutting applications require 5–10 μm, and precision cutting tools require 1–3 μm.

Controlling Internal Coating Stress

Low-temperature PVD and pulsed bias techniques are employed to reduce compressive and tensile stresses, thereby minimizing microcracks in the coating.

Nanostructured Coatings

Nanolayer and nanocrystalline coatings offer high hardness combined with strong toughness, providing significantly better impact resistance and chipping resistance than single-layer coatings.

Post-Coating Processing

Post-coating polishing, deburring, and edge rounding eliminate stress concentrations at sharp edges of the coating, significantly reducing chipping.

IV. Key Considerations for Edge + Coating Compatibility

Changing the coating alone is insufficient; it must be combined with edge rounding (radius of 0.02–0.08 mm) to ensure the coating uniformly envelops the edge, avoiding stress concentration at sharp corners, thereby maximizing wear resistance and chipping resistance.