Following ISO 14577-1, the difference between nano and microindentation is based on or in the applied load either in indentation depth. I strongly recommend the use of this standard to separate these cases. Regards.

In my point of view, the main difference concerns the comparison between the size of the indentation surface and the size of the heterogeneities of the material. The local properties measured are linked with the size of the area of contact, therefore of the homogenized properties under the contact, which are very different at the micro scale or at the nano scale.

According to ISO 14577 Part 1 ranges of hardness testing are defined:

Micro: force less than 2 N, indentation depth more than 0.2um

Nano: indentation depth less than 0.2um

Many Thanks to all of you for your valuable suggestion. ISO 14577-1 may not cover the nano scale. Being agreed with Prof Remond, Homogeneity in the material could be an important issue particularly in composite where the indenter tip may be /or may not be hit the particle and this could change the values of material properties.

The main difference is nanoindentation gives the very localized hardness whereas micro indentation gives the average hardness over the large area. For example nanoindentation gives the hardness within the grain, microhardness is average value of different grains.

Nanoindentation is applied to small volumes. I think the loads applied are also small. One micro newton to 100 milinewton is the range of load. In case of vickers or microhardness load applied can be upto 1000 gms. In case of macro hardness loads go upto 50 kg.

The major practical difference between nano and micro indentation is regarding their indentation depths of 0.1 µm and 0.1 to 100 µm respectively, secondly micro indentation provides bulk hardness of sample, whereas nano indentation can provide hardness of individual phases in the sample, it an localized approach for an heterogeneous materials.

helo, I have 11.15 GPa hardnes measure by microidentation to sample of TiZrN thin films of 100 nm, Could I compare this value with reports than find in the literature by nanoidentation (20 to 30 GPa)?

You cannot compare the measures of microindentation with those of nanoindentation cause micro indentation provides information of the bulk of material whereas nanoindentation could test simple phases

hello ahmed.

ISO 14577-1:2015 specifies the method of instrumented indentation test for determination of hardness and other materials parameters for the following three ranges: macro range: 2 N ≤ F ≤ 30 kN; micro range: 2 N > F; h > 0,2 µm; and nano range: h ≤ 0,2 µm.

The following paper (in open access and also available at ResearchGate) will give you the correct answer: "Indentation Hardness Measurements at Macro-, Micro-, and Nanoscale: A Critical Overview" E. Broitman, Tribology Letters, volume 65, Article number: 23 (2017). You you can find the comparisons, not only at different scales, but also for different materials like metals, ceramics, polymers, etc, as well as different microstructures: amorphous, poly-crystalline and single crystals. Feel free to write me back if you have any question.