Influence of agglomerate morphology on micro cold spray of Ag nanopowders
Journal of Aerosol Science(2021)
Abstract
The micro-cold spray process produces thick patterned films by impacting powders consisting of nano-to-sub-micron particles at velocities from 300 to over 1400 m/s. This process has been used extensively to produce ceramic films but has been employed only on a very limited basis to produce metallic films. The fine powders used in micro-cold spray are invariably agglomerated to some degree, but the influence of agglomerate morphology has not previously been studied for metallic particles. Here we study the effect of pre-treatments of the powder in the temperature range from room temperature to 200 °C on the powder morphology and resulting film properties of Ag. Experiments show that as the pre-treatment temperature is increased, the agglomerated powders do not densify significantly, but changes in the agglomerate morphology increase the fractal dimension. There is also evidence that increased pre-treatment temperatures increase the size of the necks between primary particles. Although the calculated impact velocities are reduced slightly for pre-treated powders compared to films produced from untreated powders, experimental results show that using pre-treated powders produces films with higher relative densities (up to 80%) and increased as-deposited conductivities (up to 3.5 S/μm). It is postulated that the pre-treated agglomerates utilize a larger fraction of the impact energy for deformation of the primary particles rather than fragmentation of the agglomerates due to increased bonding between primary particles.
MoreTranslated text
Key words
Ag,Thick film,Agglomerates,Aerosol deposition method,Nanoparticle,Metal
AI Read Science
Must-Reading Tree
Example
![](https://originalfileserver.aminer.cn/sys/aminer/pubs/mrt_preview.jpeg)
Generate MRT to find the research sequence of this paper
Chat Paper
Summary is being generated by the instructions you defined