There are various types of hard coatings.
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Improvements In Thermal Hard-Coating Technology
Andreas Szabo, Best Surface Consulting, Ludwigsburg, Germany
High-performance hard coating (HPHC) combines several techniques for optimum use in one plant. It offers improvements over conventional chemical vapor deposition (CVD) including uniform layer thickness and enhanced deposition rates, the ability to apply different layer materials and their combinations and very strong adhesion of layers to steel through the use of an alloy interface zone.
http://www.industrialheating.com/CDA/ArticleInformation/feat...

• Thermal Barrier Coatings (TBCs) of rare earth-stabilized zirconia protect turbine buckets and other key parts from high temperature damage
http://www.sulzermetco.com/eprise/Sulzermetco/Sites/MetaNavi...

Schaufelblatt airfoil, aerofoil

http://www.suliscommunication.com/language/turbine/s1.htm

Susie and Beka are the latest WPI students to work on thermal barrier coating systems for PW4000 Pratt & Whitney turbine blades, which are used in a variety of gas turbine engines for both military and commercial aircraft. Using beams of light to simulate the application of zirconia vapor during the manufacturing process, the students have developed a computer model that can predict exactly how the coating will be applied.
The zirconia coating is the key to running a hotter, more efficient engine, but sometimes it's not enough to apply a simple, uniform barrier. Specific parts of the blade may need varying thicknesses, depending on the blade's position inside a working turbine.
http://www.wpi.edu/News/Transformations/2003Spring/pw.html

Two coatings were selected for high temperature damping characterization. The first coating is a GE thermal barrier coating (TBC). The purpose of this selection is to characterize the inherent damping properties of the TBC placed on LP turbine blades for thermal design reasons rather than damping per se. The second coating selected is a hard coating from Allison Advanced Development Company (AADC).

http://www.pr.afrl.af.mil/divisions/prt/hcf/2002report/pages...