Development of High Corrosion Resistant $Mo_2NiB_2$ Boride Base Cermets for Plastic Injection Molding Machine Parts

  • Hirata, Kourou (Technical Research Laboratory, Technology Development & Environment Division, Toyo Kohan Co., Ltd.) ;
  • Iwanaga, Kengo (Technical Research Laboratory, Technology Development & Environment Division, Toyo Kohan Co., Ltd.) ;
  • Yamasaki, Yuji (Hard Materials Department, Functional Materials Division, Toyo Kohan Co., Ltd.) ;
  • Takagi, Ken-ichi (Department of Mechanical Engineering, Faculty of Engineering, Musashi Institute of Technology)
  • Published : 2006.09.24

Abstract

Injection molding of corrosive super engineering plastics and engineering plastics with various fillers is conducted under severe conditions and causes corrosion and wear problems. We have developed $Mo_2NiB_2$ boride base cermets, which have excellent corrosion-and wear-resistances, and tried to apply them into plastic molding machine parts. In this paper, the effects of V substitution for Cr on the mechanical properties, corrosion resistance and microstructure of Ni-5.0B-51.0Mo-(17.5-X)Cr-XV (mass%) model cermets were investigated. Both transverse rupture strength (TRS) and hardness increased monotonically with increasing V content and reached 2.94GPa and $87.2R_A$ at 10.0%V, respectively. The improvements of TRS and hardness were attributed to microstructural refinement.

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