"By unintentionally substituting the
wrong gas for one they intended to use for hardening tools, workers
at a small metallurgical company have accidentally hit upon a
potentially valuable method for coating objects with a hard diamond
film.
"Specialists trying to learn why and
how the method works warn that it has yet to prove its worth
in industrial processing. But if the new diamond-coating technique
proves to be as cheap, fast and effective as its inventors say,
it may revolutionize the manufacture of machine tools, automobile
engines, ships, beverage cans and much more, materials experts
say.
"Although the discovery was made two
years ago, it has not been reported in scientific journals, and
information about it has spread mainly by word of mouth.
"The discoverer of the new method is
Pravin Mistry, a 43-year-old British metallurgist who founded
a small, privately owned engineering company, QQC Inc, in Dearborn,
Michigan... Mr. Mistry's company specializes in applying coatings
to industrial objects so as to impart desirable properties.
" 'This is an interesting instance of
technology leading science,' said Dr. Rustum Roy, who heads the
Diamond and Related Materials Center at Pennsylvania State University.
'There is no question that this fellow is coating all kinds of
things with diamond, and doing it astonishingly rapidly and well,
under conditions that no scientists imagined would work.'
"Part of Mr. Mistry's method involves
four powerful and finely tuned laser beams, which interact as
they scan the surface of an object as it is coated. As Mr. Mistry
explains it, the scanning takes place in a gaseous environment,
and the intense heat at the spot where the lasers converge breaks
up some of the gas into an electrically charged plasma. The lasers
also vaporize a very thin layer of the object being coated. ...
By continuing to deposit atoms from the hot gas on the coated
object, the thickness of the coating can be rapidly increased
to up to a half inch, Mr. Mistry said.
"In 1994, Mr. Mistry's group made its
discovery while using this interacting laser technique to apply
a coating of hard titanium diboride to the surface of an aluminum
object. An error in their procedure set the stage for a surprise
that may prove to be immensely profitable for all concerned:
someone accidentally substituted carbon dioxide for the nitrogen
gas used in the process. A dense coating formed rapidly, but
it did not consist of the intended titanium diboride. It turned
out to be diamond.
"News of the discovery spread rapidly
among materials experts, who were amazed that Mr. Mistry's technique
for coating objects with diamond films was reportedly 1000 times
faster than existing diamond-coating techniques. Moreover, the
Mistry process promised to form particularly strong bonds between
the coating and the metal objects to which it was applied, a
vital requirement for hardened machine tools.
"The United States Navy, Army and Air
Force, and the Defense Department's Advanced Research Projects
Agency, as well as automotive companies, are following developments
with interest.
" 'I have seen objects coated using Mr.
Mistry's process, and I can verify that the coating is diamond,'
said Dr. Robert Pohanka, director of materials research at the
Office of Naval Research in Arlington, Virginia. 'I have visited
the plant and seen the equipment.'
"Mr. Mistry said in interviews that the
technique was in its infancy, but that all indications suggested
that the coating was cheap and could be applied in closely controlled
shapes and thicknesses, with excellent adhesion to objects.
"If the Mistry process lives up to expectations,
Dr. Pohanka said, it could be used to apply hard coatings to
gears and bearings, to cover pumps and other machinery with corrosion-resistant
coatings... and to harden engine components to reduce wear.
"Dr. Roy, whose research group has undertaken
an investigation of the scientific basis of the Mistry process,
believes it could be used almost like a paint brush to apply
coatings of diamond or other special materials. 'Mr. Mistry's
equipment is operated by robots under computer control,' he said,
'and since the method is so flexible, it might some day be possible
to coat an entire ship's hull with a film made of diamond or
some other protective material.' "
