Mechanical Properties of Plating

What Are Mechanical Properties?

In plating, "mechanical properties" is a general term for the characteristics that describe how a plated layer behaves under physical forces and friction. Alongside corrosion resistance and electrical conductivity, they are a key evaluation criterion, and selecting properties suited to the application and processing conditions determines product quality and component life.

High Hardness and Wear Resistance

This property resists deformation and wear under mechanical stress, extending component life. It is especially important in environments subject to continuous loads, such as cutting tool edges and the sliding surfaces of hydraulic shafts.

Hard chrome plating offers high surface hardness, and heat-treated high-phosphorus electroless nickel plating can achieve even greater hardness, making both leading choices for high-load applications.

Lubricity and Low Friction

This property reduces frictional resistance and maintains smooth movement over time. Because increased friction leads to heat generation, wear, and energy loss, it is essential for components with dynamic contact, such as bearings and precision guide rails.

Composite nickel plating with dispersed PTFE particles combines a low coefficient of friction with high wear resistance within the plated layer itself, making it well suited for dynamic contact components. When even lower friction is required, DLC coating is a good fit.

Ductility

Ductility is the ability of a plated layer to follow the deformation of the base material and stretch without cracking. In components that undergo press forming or bending, insufficient ductility leads to cracks and defective parts.

Copper plating, soft gold, and zinc plating are commonly selected for ductility-focused applications. However, higher hardness tends to reduce ductility, so plating types must be selected with the manufacturing process in mind.

Improved Adhesion

This property enhances plating adhesion to difficult substrates such as plastics, aluminum, and dissimilar metals. Because poor adhesion leads directly to peeling failures during use, the design of the pretreatment process forms the foundation of quality.

A combination of electroless nickel plating, widely used as an underlayer (with phosphorus content selected according to the application), and copper strike treatment can ensure stable adhesion even on difficult substrates.

Comparison of Properties

The four mechanical properties are summarized below. Because the suitable applications and recommended plating types differ for each property, it is important to define your requirements from the early stages of design.

Same Material, Different Results: Not Every Company Can Deliver the Right Plating Process

Even when the same material and plating type are specified on the design drawings, the finished quality depends heavily on the know-how of the plating company. Functional plating requires judgment backed by experience, such as coating thickness control that accounts for the trade-off between hardness and ductility, and pretreatment design for difficult substrates.

Choosing a company that can make application-specific recommendations helps you avoid quality problems. When selecting a supplier, we also recommend referring to "3 Recommended Functional Plating Companies by Industry and Component."