3069
The comparison of the wear and corrosion resistance , the microhardness and the microstructure changes of the additive-manufactured steel in different post-treated conditions with a commercial steel was carried out .
 concept or principle: wear; concept or principle: corrosion resistance; concept or principle: microhardness; concept or principle: microstructure; material: steel; material: steel
Given options, please tell me the categories of all the listed entity words.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} 
 Entities: wear, corrosion resistance, microhardness, microstructure, steel, steel 
Answer:
 concept or principle: wear; concept or principle: corrosion resistance; concept or principle: microhardness; concept or principle: microstructure; material: steel; material: steel