치과주조용 합금의 안정성에 미치는 TiN 코팅막의 영향

Abstract

Effects of TiN film coating on the stability of dental casting alloy have been researched by using various electrochemical methods. Three casting alloys (Alloy 1: 63Co-27Cr-5.5Mo, Alloy 2: 63Ni-16Cr-5Mo, Alloy 3: 63Co-30Cr-5Mo) were prepared for fabricating partial denture frameworks with various casting methods; centrifugal casting, high frequency induction casting and vacuum pressure casting. The casting temperature was 1380℃ (Alloy1,2) and 1420℃ (alloy 3). The specimens were coated with TiN film by RF-magnetron sputtering method. The microstructures were observed by using field emission scanning electron microscope (FE-SEM) and energy dispersive x-ray spectroscopy (EDX). The corrosion behaviors were investigated using potentiostat (EG&G Co, 263A. USA) in 0.9% NaCl solution at 36.5 ± 1℃. The corrosion morphologies were analyzed using FE-SEM and EDX

These results are as follows:

1. 63Co-27Cr-5.5Mo (Alloy 1) and 63Co-30Cr-5Mo (Alloy 2) show the α-Co and ε-Co phase on the matrix, and it was disappeared in case of TiN coated alloy 1 and 2. In the 63Ni-16Cr(Alloy 3), γ'-Ni2Cr second phases were appeared at matrix.

2. Corrosion potentials of TiN coated alloy were higher than that of non-coated alloy, but current density at passive region of TiN coated alloy was lower than that of non-coated alloy.

3. Pitting corrosion resistances were increased in the order of centrifugal casting(CF), high frequency induction casting(HFI) and vacuum pressure casting method(VP) from cyclic potentiodynamic polarization test.