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Incoloy 909 합금의 최적 알루미나이징 확산 코팅
권순우(S.W. Kwon),윤재홍(J.H. Yoon),주윤곤(Y.K. Joo),조동율(T.Y. Cho),안진성(J.S. Ahn),박봉규(B.K. Park) 한국표면공학회 2007 한국표면공학회지 Vol.40 No.4
An Fe-Ni-Co based superalloy Incoloy 909 (Incoloy 909) has been used for gas turbine engine component material. This alloy is susceptible to high temperature oxidation and corrosion because of the absence of corrosion resistant Cr. For the improvement of durability of the component of Incoloy 909 aluminizing-chromate coating by pack cementation process has been investigated at relatively low temperature of about 550℃ to protect the surface microstructure and properties of lncoloy 909 substrate. As a previous study to aluminizing-chromate coating by pack cementation of Incoloy 909, the optimal aluminizing process has been investigated. The size effects of source AI powder and inert filler Al₂O₃ powder and activator selection have been studied. And the dependence of coating growth rate on aluminizing temperature and time has also been studied. The optimal aluminizing process for the coating growth rate is that the mixing ratio of source Al powder, activator NH₄Cl and filler Al₂O₃ are 80%, 1% and 19% respectively at aluminizing temperature 552℃ and time 20 hours.
유리系 內의 Ferrite의 Mossbauer Spectra
安振盛,金俊植,李敬行,趙壽烈,董徹,洪致裕 동국대학교 자연과학연구소 1984 자연과학연구 논문집 Vol.4 No.-
本 硏究는 5NiO-5CdO-10Fe₂O₃-30Na₂CO₃-10SiO₂(mole %)유리계에 대한 Mossbauer parameter의 溫度依存性을 조사하였다. Mossbauer spectrum은 한쌍의 Quadrupole doublet의 중첩으로 fitting하였으며 이중 하나는 tetrahedral site,다른 하나는 octahedral site이다. 상대적인 共鳴吸收面積比로부터 octahedral site와 tetrahedral site에 대한 Debye temperature를 계산하여 본 결과 각각 418K, 449K 임을 알았다. 또한 θ?값들을 이용해 least square method로 isomer shiftdral site의 壓力依存系數 α와 2.97×10?mm/sec K, I.S(0)일때의 를 평가해본 결과 octahedral site의 α는 2.97×10?mm/sec K,I.S(0)는 tetrahedral site이고 α의 3.2305×10?mm/sec K, I.S(0)는 0.276mm/sec임을 알았다. 그리고 quadrupole splitting은 측정온도가 증가함에 따라 서서히 감소함을 알았다. The temperature dependence of the Mossbauer parameter for 5NiO-5CdO-10Fe₂O₃-30Na₂CO₃-10SiO₂(mole %) quenched glass system was investigated. The spectra were fitted as superposition of a pair of quadrupole double ; One is for the tetrahedral site and the other is for the octahedral site. From the relative absorption area ratios of the spectra, the Debye erature of two sites were calculated to be 418K and 449K for the octahedral site and the ?edrai site, respectively. From these Debye temperatures, We can see that the isomer shifts and the coefficients αof the pressure dependence of the isomer shift are 0.456mm/sec, 2.97×10?mm/sec K for octahedral site and 0.276mm/sec K, 3.2305×10?mm/sec K for ?edral site. Also, we can see that the quadrupole splittings of two sites are gradually decresed the increase of the measuring temperature.