US engineers have developed a new ceramic welding technology that could open up a range of new applications for the material.
A University of California team successfully used an ultrafast pulsed laser to melt ceramic materials along the interface and melt them.
This not only works in ambient conditions and consumes less than 50 watts of laser power, but is also more practical than current methods where parts must be heated in an oven.
Ceramic materials are biocompatible, extremely hard and shatter-proof, making them ideal for biomedical implants and protective covers for electronics. But there is a problem.
"There is currently no way to encapsulate or seal electronic components in ceramics because you would have to put the entire assembly in an oven that would burn the electronics," says lead author Javier Garay.
Ceramic is also difficult to weld together because it requires very high temperatures for melting and is exposed to extreme temperature gradients that can lead to cracks.
Series of short laser pulses along the interface between two ceramic parts, so that heat builds up only at the interface and causes local melting.
For this to work, they had to take into account the transparency of the material as well as a number of laser parameters – exposure time as well as the number and duration of the laser pulses.
The sweet spot maximized the melt diameter, minimized material removal, and cooled down in the right time to achieve the best possible weld.
"By concentrating the energy exactly where we want it, we avoid temperature gradients in the ceramic so that we can trap temperature-sensitive materials without damaging them," says Garay.
As a proof-of-concept, the researchers welded a transparent cylindrical cap to the inside of a ceramic tube. Tests have shown that the welds are strong enough to hold vacuum.
"The vacuum tests we performed on our welds are the same tests used in the industry to validate gaskets on electronic and optoelectronic devices," says Dr. First author Elias Penilla.
The process has so far only welded ceramic parts of less than two centimeters in size. It is now planned to enlarge things and consider different types of materials and geometries.
The research was published in the journal Science.