According to a paper published in Science on August 23rd,, UC-San Diego researchers have used a sub-50-watt, rapidly-pulsing laser to melt and fuse ceramics, upending traditional ceramics welding methods by dramatically lowering the temperature at which the material binds.
Traditionally, ceramics have been difficult to weld because they require immense amounts of heat to make them malleable enough to fuse. While heating ceramics to these temperatures isn’t difficult, cooling them uniformly has been challenging—if a ceramic material cools in uneven conditions, it’s susceptible to cracking, splitting and other types of catastrophic states of being.
To make their new systems for ceramic welding work, engineers optimized two aspects of the laser welding process: the laser parameters (a.k.a. the laser exposure time, the number of laser pulses, and the duration of each laser pulse) and the transparency of the target ceramic material.
“The sweet spot of ultrafast pulses was two picoseconds at the high repetition rate of one megahertz, along with a moderate total number of pulses. This maximized the melt diameter, minimized material ablation, and timed cooling just right for the best weld possible,” said Guillermo Aguilar, chair of mechanical engineering at UC Riverside.
Javier E. Garay, a professor of mechanical engineering at UC San Diego, added, “By focusing the energy right where we want it, we avoid setting up temperature gradients throughout the ceramic, so we can encase temperature-sensitive materials without damaging them.”
Given the fact that there are new ceramic materials that are both very hard and shatter-resistant, a new welding technology that can guarantee the material consistency of ceramics post-manufacture could lead to breakthrough medical devices as well as consumer electronics.
Although the ceramic laser welding process has only been tested on small samples within a lab setting, researchers are optimistic that they will be able to scale their process with relative ease. If that prediction does become reality, then many of the fragile consumer electronics that we gingerly tote about day by day could be in for a much more rough-and-tumble existence in the near future.