3822
The results revealed more uniformly distributed pitting attack on the corroded surfaces by increasing the heat-treatment temperature up to 300 °C , attributed to the more protective nature of the spontaneously air-formed passive layer on the surface of the alloy at initial immersion time .
 concept or principle: pitting; concept or principle: surfaces; process parameter: temperature; process parameter: layer; concept or principle: surface; material: alloy
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: pitting, surfaces, temperature, layer, surface, alloy 
Answer:
 concept or principle: pitting; concept or principle: surfaces; process parameter: temperature; process parameter: layer; concept or principle: surface; material: alloy