Nanoindentation Testing

Nanoindentation testing presses a diamond tip into the surface with forces as low as a few micronewtons and continuously records load versus depth. That curve reveals hardness, elastic modulus, stiffness, creep, and viscoelastic behavior, without the substrate effects that limit conventional hardness tests on thin films and coatings.

What Is a Nanoindentation Test?

A nanoindentation test presses a precisely shaped diamond tip into a material and records the applied force and penetration depth throughout loading and unloading. Analyzing that load–displacement curve gives hardness, elastic modulus, and how the material deforms. Because loads and depths are tiny, nanoindentation can measure thin films, coatings, and site-specific regions on devices and components with micron-scale lateral precision.

Why Use Nanoindentation?

Nanoindentation delivers elastic modulus, hardness, creep, stiffness, yield-related behavior, and storage and loss modulus from a single test platform. Fracture toughness (K_IC) can be estimated by measuring indent-induced cracks with SEM or optical microscopy.

Compared with conventional microhardness methods such as Vickers or Brinell, nanoindentation uses far smaller loads and depths, so it can measure a thin coating without the substrate skewing the result.

How Nanoindentation Works

Every test follows the same sequence, with dynamic and heated options added when you need them.

1. Approach and contact. A diamond tip, usually a three-sided Berkovich indenter, approaches and contacts the surface. Covalent's reference indenter keeps surface contact stable, even during long measurements on soft or time-dependent materials.
2. Load, hold, and unload. Force rises to a set maximum, holds briefly to capture creep, then releases. Load and depth are recorded continuously throughout.
3. Analysis. Hardness is calculated from the maximum load and the contact area. Elastic modulus comes from the slope of the unloading curve, using the Oliver–Pharr method.
4. Dynamic and temperature options. In SINUS mode, a small oscillating load is added to measure stiffness and storage and loss modulus continuously with depth. A heated stage extends measurements from room temperature to about 200 °C.

Nanoindentation for Thin Films and Coatings

Thin films are where nanoindentation is most valuable, and where test design matters most.

• The 10% rule: keep indent depth below about 10% of the film thickness so the substrate does not influence the hardness result. Modulus is more sensitive, so very thin films may need shallower indents or modeling.
• Depth profiling: SINUS or progressive multi-cycle loading shows how hardness and modulus change with depth, separating the film's response from the substrate's.
• Film vs. film-plus-substrate: our scientists choose loads and depths based on your film thickness and roughness, and report whether results reflect the film alone or the composite system.
• Adhesion and wear: pair indentation with nano scratch testing to measure coating adhesion, delamination loads, and scratch resistance.

For broader programs, see our coating testing services.

Key Differentiators

Key capabilities include SINUS-mode dynamic mechanical testing and a reference-indenter approach that helps maintain reliable surface contact during long-duration measurements or testing of relatively soft/time-dependent materials.

Sample Requirements

Samples should be solid and preferably flat. Non-flat samples may require mechanical preparation. Surface roughness may also need to be characterized so that an appropriate load and penetration depth can be selected.