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  HOME > Characteristics of Fine Ceramics > Physical - Hardness 
Physical
Hardness Rigidity Toughness Specific Gravity
Fine Ceramics: Harder Than Stainless Steel

The signature feature of Fine Ceramics (also known as “advanced ceramics”) is their extreme hardness; as a result, they have valuable use in high-performance applications, such as industrial cutting tools for milling and grinding metals.

A material's hardness is determined by measuring the size of an indentation made by a sharp diamond pressed strongly onto a material specimen. The hardness of alumina ceramics is nearly three times that of stainless steel; silicon carbide is more than four times harder than stainless steel. This extreme hardness is one of many unique properties that makes Fine Ceramics "super materials" for modern technology.


Applications: Cutting tools and bearings.

Description
 
Hardness

The hardness of Fine Ceramics is generally indicated using a Vickers hardness number. The method for measuring the hardness of Fine Ceramics is defined in JIS R 1610 (ISO 14705: 2000). Vickers hardness is a resistance value obtained by pressing a diamond indenter onto a test specimen.

Extreme hardness is the primary feature that endows Fine Ceramics with their superior wear resistance. This has led to the use of Fine Ceramics in a wide range of applications, including pump components, cutting tools, seal rings, bearings and a multitude of wear-resistant components for industrial equipment.

Vickers Hardness
Image : Graph of Vickers Hardness  Fine Ceramics / Silicon Carbide22.0GPa, Alumina15.7GPa, Silicon Nitride13.9GPa, Zirconia13.2GPa, Metals / Cemented Carbide15.5GPa, Stainless Steel5.0GPa (Measuring method / Vickers hardness, which is used for fracture toughness calculations based on the IF method specified in JIS R 1607-1990)

  For more information, please see Excerpt of Graph Values.

Strength of Fine Ceramics

The strength of Fine Ceramic materials may be influenced by the presence of physical defects within the material, such as scratches, internal foreign substances and crystals with abnormal grain growth. Because larger Fine Ceramic components tend to have larger internal defects, larger specimens display less strength compared to smaller ones.

A major difference between metals / plastics and Fine Ceramics is that the strength of Fine Ceramics is significantly influenced by variations in their fabrication and manufacturing processes, whereas the strength of metals and plastics is determined by their intrinsic material characteristics.


Wear Resistance
Fine Ceramics that exhibit excellent hardness also greatly surpass most metals in wear resistance. During wear resistance tests, small glass beads were continously sprayed at high speeds onto Fine Ceramics and metals for extended periods of time. The Fine Ceramics displayed only about 10 percent of the abrasion observed in the stainless steel samples. Additionally, during a test in which disks with Fine Ceramics and metals attached were continously rotated in wet sand for eight hours, the Fine Ceramics displayed considerably less abrasion.
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Learning About Fine Ceramics
   
Fine Ceramics in Daily Life
Hardness Rigidity Toughness Specific Gravity
   
 
The term "Fine Ceramics" is interchangeable with "advanced ceramics," "technical ceramics" and "engineered ceramics." Use varies by region and industry.
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