Ceramic Material Hardness

Silicon carbide is more than four times harder than stainless steel.

Ceramic material hardness.

The hardness of ceramic materials is a property which is of high significance as it relates to the ability of the material to withstand penetration of the surface through a combination of brittle fracture and plastic flow. Its value helps to characterize resistance to deformation densification and fracture. It is a very hard material. Development of ceramics helps to decrease the demand in industries.

In the world of technical ceramics there are two materials which are only surpassed by diamond in terms of hardness and both are used by precision ceramics as a base material for a wide range of technical components in an equally wide field of applications. Compare to other materials ceramics have some unique properties. The hardness of alumina ceramics is nearly three times that of stainless steel. Often hardness of ceramic material as with other materials is directly equated to wear resistance.

The knoop hardness test is most practical for the purpose of ceramic coating tests as only a small indentation is required to evaluate and measure a material s hardness. Ceramics play an important role in our day to day life. The ionic and covalent bonds of ceramics are responsible for many unique properties of these materials such as high hardness high melting points low thermal expansion and good chemical resistance but also for some undesirable characteristics foremost being brittleness which leads to fractures unless the material is toughened by reinforcing agents or by other means. Hardness is crucial for cutting tools wear and abrasion resistant parts prosthetic hip joint balls and sockets optical lens glasses ballistic armor molds and dies valves and seals.

Knoop and vickers are the only standard hardness testing procedures which are also suitable for hard materials 1000 hv like ceramics. Its major use is in metallurgical applications involving molten aluminum. Hardness is one of the most frequently measured properties of a ceramic. Ceramics are oxides carbides nitrides borides of metal ions.

However its mechanical properties are poor. A material s hardness is determined by measuring the size of an indentation made by a sharp diamond pressed strongly onto a material specimen. Generally they are inorganic and non metallic. Ceramics may reach a hardness close to 2000 hv depending on the material composition.