UNIVERSITY PARK, Pa. — Sarah Lowum, a materials science and engineering doctoral student in Penn State’s College of Earth and Mineral Sciences (EMS), received a 2019 Graduate Research Fellowship from the National Science Foundation to investigate how to improve the cold sintering process (CSP). She is one of seven EMS students and 24 Penn State students to receive the honor.

Sintering is a process that enables the densification or compaction of particles into a solid mass of material through the application of heat and sometimes pressure. A simple example of pressure-assisted sintering is forming a snowball from loose snow.

Lowum is investigating CSP, a new technology which was first developed by Penn State researchers in 2016. CSP can be more sustainable than other sintering methods.

What distinguishes CSP from traditional thermal sintering is the temperatures applied in the process. Unlike typical ceramic sintering, which is often carried out at temperatures exceeding 1,800 degrees Fahrenheit, cold sintering can densify particles at temperatures below 575 degrees. It also requires much less time; materials can be cold sintered in less than 15 minutes where other methods can require hours.

Basic phase changes form the mechanisms for the process. In CSP, a specific liquid is added to the ceramic powder. This allows particles to dissolve and rearrange, resulting in a tightly packed, densified material. 

Lowum’s research focuses on expanding the range of materials that can be cold sintered by manipulating variables that affect the process, like pressure, composition of the liquid solution and compaction time.

“I’m trying to better understand the mechanisms facilitating cold sintering,” Lowum said. “By exploring the science of the process, we can broaden the applications for manufacturing.”

CSP is still in its early stages of research, according to Lowum. Low temperature densification allows the use of polymers and can maintain a higher purity in materials; these possibilities have implications for new technologies. Flexible electronics and more sophisticated electronic capacitors are two potential developments. The method, due to its reduced energy costs, can be more economical and environmentally friendly, said Lowum.

With the fellowship, Lowum’s goal is to make innovations like these possible.

“Receiving this award was a great honor,” Lowum said. “It’s exciting to have been selected from such a large pool of applicants.”

Lowum’s adviser is Jon-Paul Maria, professor of materials science and engineering.

“Sarah has outstanding academic and laboratory skills,” Maria said. “I am confident that her unique approaches to cold sintering will reflect positively on materials research at Penn State.”

The NSF Graduate Research Fellowship Program recognizes and supports outstanding graduate students in NSF-supported science, technology, engineering and mathematics disciplines who are pursuing research-based master’s and doctoral degrees at accredited institutions in the United States. About 12,000 students apply annually and 2,000 receive awards.