努氏(Knoop)硬度是维氏硬度试验方法的一种发展,在许多方面比起维氏硬度来,努氏硬度有它独特的优点。在相同硬度时,采用同样的负荷,努氏硬度的压痕要比维氏硬度的压痕浅得多(大约浅1/3),因此,它比显微维氏硬度更适合于一些极薄层和一些极薄零件的检查。例如表面极薄硬化层、渗层、镀层的检查。如果压头压到同样 Knoop hardness is a development of the Vickers hardness test method that in many ways has its unique advantages over Vickers hardness. At the same hardness, with the same load, the impression of Knoop hardness is much shallower (about a third) than the indentation of Vickers hardness, so it is more suitable than some for micro Vickers hardness Layer and some very thin parts inspection. For example, the surface of the ultra-thin hardened layer, diffusion layer, coating inspection. If the pressure head pressed to the same