Ceramics are inorganic non metallic materials. The metal oxides are typical examples of the ceramics, but also other elements such as carbides and nitrides are also included. Porcelain, glass, brick and resources are some examples of traditional ceramics. Over the past 30 years, the advances in materials science of ancient pottery have enough turns fragile material to withstand the harsh environment of the engine. Hardness is the resistance of the plastic bending caused by bleeding. Sometimes refers to opposition to the hardness of the material to scratching or abrasion. Tests of hardness in many cases relatively quickly and can replace the minimum number of tensile test. Resistance can be from a small sample of the material to be measured without breaking.

The hardness is one of the most commonly measured with a ceramic. Its value can resist deformation to characterize compaction and fracture. The resistance is important for common cutting tools, wear and abrasion, hip balls and sockets, sunglasses, optical lenses, ballistic weapons, tools and molds, valves and seals. In fact, many details of the ceramic hardness list of minimum requirements.

The hardness of the ceramic supply is a characteristic that is resisting on a different dimension of the material, the ability to penetrate the surface by a combination of brittle fracture and plastic flow. Often, the hardness is directly equated with wear resistance. This is a misunderstanding with metal parts for several years and is a criterion of selection completely false in terms of technical ceramics. Global standards for the strength of the ceramics tend to have different requirements for the control of the loading rate during the cycle of bloodletting. An analysis of the literature shows that the loading rate may affect the hardness measured several times. Given the uncertainty on this issue, further investigations in the field of redemption prices of the shop are in a steel, silicon and aluminum oxynitride. Modern methods of measuring the static strength limit the speed of the load, but there are big differences in the requirements. The requirements are constraints on the speed of the penetrator, the cycle time or to avoid a vague declaration of the impact. Ceramics are more brittle than metals and can be similar stiffness (modulus) and strength similar to have, especially in the compression. But in a tensile test that are suitable, and fail at a stress in a much weaker application. The reason is often the ceramic surfaces contain tiny cracks (Griffith cracks), which increases the tension. The oldest method of hardness testing to a disk file in the test can and see how difficult it is, the material must be removed. The following method is called the Rockwell hardness test. It is used most frequently in the Stamps of the company. Resistance is viewed in two different scales. The most common is the “C” scale, that a diamond membrane used. Lowest accepted to use “B” scale, with a ball similar to the Brinell test. Brinell hardness is achieved by a steel ball hard or carbide of a given diameter under a given load on the surface of a material and measuring the diameter of the depression after the test left determined. The Brinell hardness number, or simply the Brinell number is calculated by dividing the load obtained housed in kilograms by the actual area of bleeding and millimeters.The square is a measure of pressure, but the units are seldom confirmed.

Vickers hardness test is the standard method for measuring the strength of metals and ceramics, particularly those with high resistance surfaces: the surface under normal pressure for a period of normal time through a pyramid-shaped diamond. The diagonal of the impression is gained to read with a microscope and the Vickers hardness value from one table for the conversion. The relative hardness of a material is determined by the examination of the Knoop indent. In this test, pressed a pyramidal diamond indenter with apical angle of 130 and 172 30ISE against a material. Make an impression with a diagonal thombohedral seven times more than others. The hardness of the material is determined by the penetration depth of the Knoop indenter.