What are the most effective (or proven) surface treatments or coatings applied to steel powder metallurgy (PM) tools? Are there favored choices for abrasive wear and/or scuffing wear? Can a coating or surface treatment of tools reduce friction, enoug

摘要

A Most of the coatings currently in use for steel PM tools were not developed for the PM compaction process but were adapted from other metal-cutting or -forming operations. The combination of wear resistance, lubricity, anti-galling and close tolerance clearances between tool members limits the coating systems worthy of consideration. Typically, tool coatings fall into one of four categories: plating; diffusion coating; physical vapor deposition (PVD) or chemical vapor deposition (CVD); lubricious. Issues regarding tool coatings include thickness and coating-deposition tolerance, adhesion, surface smoothness, ability to repair/recoat, ability to coat blind areas of the tooling, and the coating cost. A previous publication on tool coating systems discusses these issues in more detail (see M.E. Trueblood, D. Gay and H.I. Sanderow, "Effect of Tool Coatings and Die Lubrication Techniques on the Warm Compaction Response of Insulated Iron Powders," Advances in Powder Metallurgy & Particulate Materials - 1999, compiled by C.L. Rose and M. H. Thibodeau, Metal Powder Industries Federation, Princeton, NJ, 1999, vol. 1, part 2, pp. 17-32).