Laser yields knobby diamond film.

Five years ago, scientists zapping carbon with a laser of unusually high intensities discovered they had created new forms of this common element. One, called amorphic diamond, represents a "true" diamond material, with a hardness that can match that of natural diamond, says Farzin Davanloo, a physicist at the University of Texas at Dallas. He, Carl B. Collins, and their Texas colleagues have now demonstrated that they can deposit this diamond film on many materials, including computer disks, medical implants, and infrared optics.

Most researchers make synthetic diamond films using a process called chemical vapor deposition. This technique requires high temperatures and reaction environments that would destroy many of the materials researchers seek to coat, says Davanloo. Although his groups new technique uses lasers with 500 billion watts per square centimeter to create a carbonion plasma, that plasma never heats the material it settles on to more than 35[degrees] C, he notes. He and his colleagues have coated 10-centimeter squares of silicon, titanium, gold, silver, aluminum, copper, stainless steel, ceramics, and polyimide.

Amorphic diamond consists of diamond nodules in a sea of other carbon forms. The researchers adjust the laser to vary the nodule density and thus the film's hardness, says Davanloo.

These diamond films still cost more than those made by chemical vapor deposition, but two companies are developing commercial applications of the new process, Davanloo says.