SYMPOSIA PAPER Published: 01 January 1995

DDW Testing of Thermal Spray Coatings


A cyclic wear-corrosion test has been established for evaluation of thermal spray coatings. While this test equipment is now used in the paper industry for assessments of thermal spray coatings on Yankee dryers, it may also be modified for other sliding wear corrosion applications. Yankee dryers have been thermally sprayed for 20 years with a marginal success rate; now for the first time, it is possible to predict their performance by DDW tests. The method drips (D), dries (D) and wipes (W) a specific chemical(s) on the surface of the heated, thermally-sprayed, specimen and the DDW cycles repeat every few seconds, monotonously. Both surface profilometer and microscopic methods are used to evaluate the material-environment interactions. DDW test results are described for the determination of environmental effects on thermal spray coatings.

Author Information

Bowers, DF
Packer Engineering, Inc., Naperville, IL
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Developed by Committee: G01
Pages: 37–48
DOI: 10.1520/STP14037S
ISBN-EB: 978-0-8031-5301-1
ISBN-13: 978-0-8031-2014-3