High-Temperature Sliding Wear Testing of Cathodic Arc Physical Vapor Deposition AlTiN- and AlTiON-Coated Hot Work Tool Steels

Abstract

Thin hard coatings provide the much needed protection for steel thixoforming tools that must resist wear at high temperatures. The wear resistance of AlTiN-and AlTiON-coated hot work tool steel was investigated at 1023 K (750°C), measured to be the cavity surface temperature shortly after the steel slurry was forced into the thixoforming die. The wear tests were repeated in exactly the same fashion with uncoated tool steel samples to identify the impact of AlTiN and AlTiON coatings on the high-temperature wear performance of X32CrMoV33 tool steel. The nature, the thickness, and the adherence of the oxide scales impact the tribological behavior. The poor adherence and limited ductility of ferrous oxides promote the failure of the oxide scale impairing the resistance to wear of the hot work tool steel at elevated temperatures. The substantial softening in the X32CrMoV33 hot work tool steel is also critical in the wear volume loss it suffers. AlTiN and AlTiON coatings, on the other hand, form a stable and protective oxide surface layer at high temperatures and therefore provide an enhanced resistance to oxidation. The latter is relatively more resistant to oxidation and is thus the better of the two coatings tested in the present work.

Elektrokimyasal olarak borlanan düşük karbonlu çeliğin yüksek sıcaklık aşınma ve oksidasyon davranışı

“…Aşınma sırasında oluşan oksitlerin bir yağlayıcı görev üstlendiği ve sürtünme katsayısını azalttığı daha önce birçok çalışmada vurgulanmıştır [10,11] olası bir nedeni olarak hematit (Fe2O3) fazının katı bir yağlayıcı gibi davranan manyetit (Fe3O4) fazına dönüşümü olarak ileri sürülmektedir [12]. Ancak sıcaklığın 600℃'ye yükselmesiyle RAH değerinin artması işlem görmemiş AISI 1020 çeliğinin yumuşaması, yüzeyde oluşan Fe3O4 veya Fe2O3 oksitlerin zayıf yapışması ve düşük sünekliği [13] ile açıklanabilir.…”

A comparative study of surface deformation and quality of brass workpiece in contact with coated dies by pin-on-disc testing

“…The lowest oxidation was observed at the tip of the duplex-TiN-TiAlN pin. This was because of the formation of Al 2 O 3 oxide on the surface of the duplex-TiN-TiAlN pin [29,30]. Due to the contact of brittle Al 2 O 3 with hard Fig.…”

“…12 Quantified values of R a , R sk , and R ku in the sliding direction (A direction in Fig. 1a) of wear tracks at a 25°C, b 250°C, and c 700°C counterface (Sapphire at 600°C [29] or 440C stainless steel at 700°C [30]), hard abrasive particles were formed. The particles created triple tribo-system and increased the coefficient of friction.…”

Thermal Fatigue Testing of Duplex-Coated Hot Work Tool Steels at Elevated Temperatures

“…Such coatings must offer thermal and chemical stability as well as adequate resistance to thermal fatigue, oxidation and abrasion by the slurries. There have been several attempts to explore the potential of PVD coatings in thixoforming tools [14,[16][17][18][19]. There have been several attempts to explore the potential of PVD coatings in thixoforming tools [14,[16][17][18][19].…”