Conventional reactors are used for atomic layer deposition onto powders

JUL 31, 2020

Rotary drum mixer is adapted to fit a conventional tubular hot-walled atomic layer deposition reactor, speeding up reactant transport and allowing deposition onto powders without reactor specialization.

Savannah Mandel

DOI: 10.1063/10.0001748

Conventional reactors are used for atomic layer deposition onto powders internal name — Conventional reactors are used for atomic layer deposition onto powders lead image

Coating powders with thin layers using atomic layer deposition (ALD) is commonly used to enhance the stability of materials for batteries and catalysis. Previously, thinly coating a large amount of powder using ALD required the use of specific reactors such as fluidized bed systems. Coile et al. have overcome this limitation by modifying a rotary drum mixer to be compatible with conventional tubular hot-walled ALD reactors and using it to deposit the coatings on powders.

The rotary drum reduces the time required to transport reactants by mixing the powder. It allows the coating of up to 75 grams of silica gel powder with a surface area of about 1500 m² in viscous flow operation and provides precursor utilization of up to 70%. It does not require a fluidized bed system and is not limited to static precursor exposures as previous rotary systems were.

The researchers studied rotation speeds in relation to saturation times and tested the system using a porous silica gel as their model powder substrate.

“We report a simple modification that allows common reactors that are designed to coat small flat coupons to be repurposed for coating hundreds of grams of powder,” said author Matthew Coile. “The work is enabling and helps to democratize ALD on powders so that more people can take advantage of this approach and contribute to advance this work.”

In the future, the authors hope to use the rotary drum system for coating powders in research on energy storage and catalysis.

“Hopefully, this rotary drum will allow more researchers to contribute and accelerate the timeframe for realizing meaningful technological advancement,” said Coile.

Source: “High-capacity rotary drum for atomic layer deposition onto powders and small mechanical parts in a hot-walled viscous flow reactor,” by Matthew W. Coile, Matthias J. Young, Joseph A. Libera, Anil U. Mane, and Jeffrey W. Elam, Journal of Vacuum Science and Technology A (2020). The article can be accessed at https://doi.org/10.1116/6.0000274 .