ISO 9385

Introducing ISO 9385 - Industrial Physics

ISO 9385 is an international ISO standard that’s used to guide accurate knoop hardness testing of glass and glass-ceramic samples.

Knoop hardness testing uses an elongated, rectangular shaped indenter that’s pushed into the surface of a sample. This produces an indentation which can then be measured, revealing the hardness of the material.

This type of microhardness testing is typically performed at lighter loads, while the shape of the probe means it is suitable for samples needing indentations that are close together.

Is knoop testing the correct approach?

There are two main methods of microhardness testing that can be used for glass and glass-ceramics. These are the vickers hardness test and the knoop hardness test…so which one is the best option?

Well, within the ISO 9385 standard documents you will learn that a study by the International Commission on Glass (ICG) compared both procedures. Their microhardness testing study found that the knoop hardness test is preferable.

The knoop hardness testing method

Through effective knoop hardness testing you can measure permanent changes to the surface of your glass samples after indentation with a solid material.

Using a knoop hardness tester you force the knoop indenter vertically into the surface of a test specimen of glass or glass-ceramics. You apply various test forces for 20 seconds within a six minute period. Following this, it’s time to measure the length of the long indentation marks using a microscope.

The knoop indenter consists of a diamond-tipped right pyramid with a rhomboid base. It's a good idea to test the microhardness tester’s functionality regularly - including the knoop indenter itself for any damage.

ISO 9385 testing devices

So, how can Industrial Physics improve your ISO 9385 testing?

UTS Tru-Blue mVT (MicroVT)

A highly accurate, semi-automated microhardness testing system. Just what you need for effective and insightful ISO 9385 testing!

Our microhardness tester is perfect for both vickers testing and knoop testing from 10g up to 1KG. Our state-of-the-art electronics and high-quality optical displays make running tests on this versatile microhardness tester both quick and easy.

Your global test and inspection partner for ISO 9385