Synthesis and Characterization of ZrO₂ Coatings on Micro End Mills With Sol–Gel Processing

The objective of this paper is to develop a coating method for placing ultrathin zirconia films, fabricated using sol–gel methods, onto micro end mills. Sol–gel synthesis is investigated because of its potential as a low energy and inexpensive method for depositing a variety of wear resistant and chemically stable oxide coatings that could potentially extend tool life. Two sol–gel based deposition methods are investigated: dip-coating and electrophoretic deposition (EPD). The coatings are deposited on 300-μm-diameter micro end mills. Initial results suggest that sol–gel coating methods can produce the required coverage and conformity in the cutting zone. However, preliminary findings show that the coating is removed in the cutting zone after a short time of machining (6 s). The tool pretreatment and extent of sintering, which affect surface adhesion coating mechanical properties, require further study and optimization.