The Diamond Indentation Test
While the Brinell test uses a massive steel or tungsten ball to crush the metal, it fails when testing extremely thin sheets of metal or ultra-hard ceramics.
The Vickers Hardness Test, developed in 1921, solves this by using a tiny, perfectly cut Diamond Pyramid instead of a ball.
The Micro-Hardness Advantage
Because diamond is the hardest known material on Earth, the Vickers indenter will never deform, no matter what you test it against. Furthermore, the test uses much lighter loads (often just 1 to 50 kg of force), meaning it can test the microscopic surface hardness of a tiny gear inside a Swiss watch without completely destroying the part.
After the diamond is pressed into the metal, the engineer looks through a microscope and measures the lengths of the two diagonal lines of the square-shaped crater left behind.
The Vickers Equation
The result is the HV (Hardness Vickers) number. Because both Brinell and Vickers calculate hardness based on the surface area of the indentation, their scores are actually very comparable in the lower ranges!