9370
Cu-Sn nanoparticles have been injected to the stainless steel via binder jetting process , aiming to fill the voids between steel particles and reduce the microstructure heterogeneity in the spot welds .
 material: Cu-Sn nanoparticles; material: stainless steel; manufacturing process: binder jetting; concept or principle: voids; material: steel; concept or principle: particles; concept or principle: microstructure heterogeneity; engineering feature: spot welds
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: Cu-Sn nanoparticles, stainless steel, binder jetting, voids, steel, particles, microstructure heterogeneity, spot welds 
Answer:
 material: Cu-Sn nanoparticles; material: stainless steel; manufacturing process: binder jetting; concept or principle: voids; material: steel; concept or principle: particles; concept or principle: microstructure heterogeneity; engineering feature: spot welds