Incoloy-800H超合金之高溫氧化行為研究

High-temperature Oxidation Behavior of Superalloy Incoloy 800H

本文探討Incoloy 800H超合金（Iny-800H）在750 ~ 1050℃空氣的氧化行為以及950℃不同氧分壓下（Po2 = 0.01 ~ 1 atm）的氧化特性。研究結果顯示，800H合金之氧化行為皆遵守拋物線律，並和溫度與氧分壓無關。此外，合金的氧化速率隨著溫度的上升而增快；而在不同氧分壓下，合金之氧化速率亦隨著氧分壓增加而變快，顯示合金在氧化後所產生之氧化物呈現P型半導體之特徵。由微結構分析得知，合金氧化後氧化層表面之氧化物主要為FeCr2O4為主，而較內層氧化物則以Cr2O3為主；此外在基材近氧化層處亦有少量的Al2O3內氧化粒子生成。

The oxidation behavior of Incoloy 800H (Iny-800H) was studied over the temperature range of 750 ~ 1050 ℃ in dry air and at 950 ℃ in various oxygen-containing atmospheres ( Po2 = 0.01 ~ 1 atm). The oxidation kinetics of the alloy followed the parabolic-rate law in all cases, regardless of temperature and oxygen pressure. In addition, the oxidation rate constants (kp values) increased with increasing temperature and partial pressure of oxygen. This observation further indicated that the scaling behavior of the alloy exhibited a P-type semiconductivity. Based on microstructural analyses, duple scales formed on Iny-800H, consisting of an outer layer of FeCr2O4 and of an inner layer of Cr2O3. In addition, minor amounts of internal oxidation of Al2O3 precipitates were also observed in the substrate beneath the scales.