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Regarding mechanical properties , zirconia ceramics are considered to have high strength , hardness , wear resistance , resistance to corrosion , modulus of elasticity similar to steel , coefficient of thermal expansion similar to iron , and the highest fracture toughness among the most used ceramics .
 concept or principle: mechanical properties; material: zirconia ceramics; machanical property: strength; machanical property: hardness; machanical property: wear resistance; machanical property: resistance; concept or principle: corrosion; machanical property: modulus of elasticity; material: steel; machanical property: coefficient of thermal expansion; material: iron; concept or principle: fracture; material: ceramics
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
Answer:
 concept or principle: mechanical properties; material: zirconia ceramics; machanical property: strength; machanical property: hardness; machanical property: wear resistance; machanical property: resistance; concept or principle: corrosion; machanical property: modulus of elasticity; material: steel; machanical property: coefficient of thermal expansion; material: iron; concept or principle: fracture; material: ceramics