As Corning Environmental Technologies celebrates 20 years of cleaning the air with light duty diesel particulate filters (DPFs), the business is reflecting on how a critical product innovation progressed. In the second article of this three-part series, we look at the science behind aluminum titanate.
Corning PN filters had failed to deliver the desired performance, but drawing on Corning’s deep technical expertise and collaborative culture, R&D leadership quickly assembled a handful of cross-functional teams to evaluate a range of alternate materials – Pollucite, beta-eucryptite lithium aluminate spinel (bE-LAS), and aluminum titanate among them. The criteria were demanding: the new material needed to withstand extreme temperatures, have high heat capacity, offer high filtration efficiency, demonstrate excellent thermal shock resistance, be chemically stable, and scalable for rapid, large-scale production on current assets.
Several material candidates were quickly ruled out due to factors like high cost, low heat capacity, inadequate thermal shock resistance, and manufacturing complexities that made them impractical given the tight timeline and scale-up that would be required.
The turning point came when a team of young scientists around Steven Ogunwumi and Patrick Tepesch invented a stabilized aluminum titanate ceramic oxide composition that could be processed in existing manufacturing assets.
Fortunately, foundational research on aluminum titanate had been conducted by Corning scientists in the 1980s. Decades later, the experience of the original researchers proved invaluable as the team revisited aluminum titanate as a filter material.
“Through that earlier work, we gained a deep understanding of microcracking in aluminum titanate,” said Patrick Tepesch, Fellow, and a member of the Corning team that developed the material that would later be commercialized as Corning® DuraTrap® AT filters. “I’m not sure we could have learned fast enough if we didn’t have that base to start from – it was an incredibly tight timeline.”
Steven Ogunwumi, now the Program Director of Academia & Government Programs, Corning, and his team took a rigorous, methodical approach to validate AT’s suitability for automotive filter applications. They first analyzed the filters’ operating conditions, determining both the peak temperatures encountered and the duration of exposure at those temperatures.
Utilizing Corning’s strong ties to the automotive industry and its deep technological expertise, the team designed a pivotal experiment, subjecting aluminum titanate samples to the highest expected temperature for more than twice the length of time the filters would experience in actual service. The outcome was clear and compelling: the material’s properties remained unchanged, providing Corning with the confidence to move forward. Over the next few months, the Research team worked tirelessly alongside the Development team to develop a novel particulate filter material based on stabilized aluminum titanate ceramic oxide: Corning DuraTrap® AT filters.
DuraTrap AT filters offer a combination of high volumetric heat capacity and exceptional thermal shock resistance, both of which are critical for ensuring the filter can withstand rapid temperature fluctuations and repeated soot regeneration cycles—key requirements for reliable long-term performance in modern diesel vehicle emissions systems.
A multitude of talented Corning employees had gotten the technology this far; even more would be needed to get it into production.
> Read the last article of this series: How Corning transformed diesel emissions control with aluminum titanate technology
> Back to the first article of this series: 20 years of Corning® DuraTrap® Diesel Particulate Filters: Innovation that powers cleaner air
