https://phys.org/news/2018-10-fine-tuned-laser-welds-effectively.html

A new type of laser launched in 2015 by US company IPG Photonics came to the rescue: This fiber laser is cooled energy-efficiently using air instead of water, requires less maintenance, works more consistently and is more compact. Initial tests conducted by Medtronic, however, revealed that the weld seams now have black edges that look a lot like soot – extremely problematic for implants. Therefore, Medtronic's Sébastian Favre approached Empa materials specialists Patrik Hoffmann and Marc Leparoux from the Advanced Materials Processing Laboratory at the Thun site, who initiated a project to optimize the new laser for usage with titanium. The project was funded by Innosuisse, the former Commission for Technology and Innovation (CTI).

Titanium nanoparticles look black