Advanced machine tool coatings for Ti machining are presented. The coatings
of the present invention provide for protection from chemical reactivity and higher
cutting temperatures. In accordance with one embodiment of the present invention,
a coated machine tool is provided including a relatively hard underlayer and a
chemically inert overlayer. The relatively hard underlayer is formed over the base
material of the machine tool. The overlayer is formed over the underlayer, is chemically
inert with respect to titanium, and comprises an oxide of yttrium or another metal
oxide. In accordance with another embodiment of the present invention, a coated
machine tool is provided including an alkaline earth metal fluoride overlayer that
is substantially chemically inert with respect to titanium. The overlayer includes
a metal intermixed with the metal fluoride. The intermixed metal is softer than
the base material.