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Therefore , these coatings improve the Cu NP packing density and increase the temperature required for necking to occur which leads to better sintering of the Cu NP ink samples .
 coatings, Cu, density, temperature, necking, sintering, Cu, ink
Please list all entity words in the text that fit the category. Output format is "word1, 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:
 coatings, Cu, density, temperature, necking, sintering, Cu, ink