ABSTRACT
This chapter addresses the grain (mainly size) dependence of indentation hardness (H). Indenter geometries are either spherical or pyramidal, the latter primarily Vickers or Knoop (designated respectively by subscripts V and K), which are dominant in ceramic testing and the focus of this chapter. Scratch hardness is also used some, but primarily as a test to simulate machining or wear; hence it is covered in conjunction with these topics in Chapter 5. Though grain size (G) is commonly the dominant parameter, grain shape and orientation, and especially their combination, can be important, and while studied little, are noted and discussed to the extent that data allows.
