本研究首先分析鋁合金AL 1100、AL 2024、AL 5083、AL 6061、AL 7005在高真空環境下加熱溫度為600 K、700 K、800 K時之放射率；再與相同的合金和加熱溫度在開放環境下之放射率行為做比較，藉此討論試件有氧化與無氧化對表面放射率的影響；最後探討利用多光譜輻射測溫法搭配一階線性放射率模組去推測鋁合金表面溫度之結果，以了解氧化效應對溫度推測的影響。
高真空環境之鋁合金放射率分析：(1)為了避開大氣中的水氣與二氧化碳的影響，故波長選取範圍為2.8 µm到4.2 µm，在此波段內此五種鋁合金放射率皆隨波長的增加而逐漸下降；(2)整體而言，鋁合金表面放射率皆隨加熱溫度增加而上升；(3)鋁合金表面放射率不會隨著加熱時間增加而改變；(4)加熱溫度為600 K與700 K時，合金成份對放射率的影響並不大。但是當加熱溫度為800 K時不同合金成份之放射率明顯的差異。
鋁合金有氧化與無氧化對放射率的影響：(1) 大部份鋁合金有氧化的放射率皆大於無氧化的放射率，除了AL 2024與AL 7005，因為熔化造成表面粗糙度增加及高溫加熱時表面色澤的改變導致無氧化的放射率大於有氧化的放射率。整體而言，有氧化與無氧化之放射率皆隨著加熱溫度增加而上升；(2) 鋁合金於開放環境之放射率隨加熱時間增長而明顯上升，但在真空腔體內之鋁合金其放射率卻不隨加熱時間增長而改變，因為氧化層會隨著時間增加而成長進而造成表面放射率上升；(3) 合金成份對放射率的影響在氧化下比無氧化呈現顯著的差異。
應用多光譜輻射測溫法搭配一階線性放射率模組於溫度推測：(1)應用於推測無氧化試件表面溫度之波段的選擇以3 µm到4 µm的結果最好；(2)應用於推測無氧化試件表面溫度的結果比推測有氧化試件表面溫度的結果來的好；(3)當放射率模組越能模擬鋁合金表面放射率行為，則所推測溫度誤差將越小。

In this study, experiments were first conducted to investigate the surface emissivity for AL 1100, AL 2024, AL 5083, AL 6061, and AL 7005 at 600 K, 700 K, and 800 K under high vacuum. The data were compared with that of the same alloys at the same heating temperature under an open-air environment in order to analyze the effect of surface oxidation on emissivity. Multispectral radiation thermometry (MRT) with first-order linear emissivity model (LEM) was then applied to predict the surface temperature and examine the effect of surface oxidation on temperature determination as well.
For emissivity behaviors of aluminum alloys under high vacuum: (1) emissivity decreases with increasing wavelength in the wavelength range from 2.8 μm to 4.2 μm which is chosen to exclude the atmospheric effect of water vapor and carbon dioxide; (2) overall, emissivity increases with increasing temperature; (3) emissivity dose not change with heating time; (4) the effect of alloy composition is minor at 600 K and 700 K, but much stronger at 800 K.
For the effect of surface oxidation on emissivity: (1) most oxidized samples have higher emissivity than unoxidized samples, except AL 2024 and AL 7005. The exception is due to roughened surface caused by the onset of melt and the change of surface color at high heating temperature. Overall, emissivity of both oxidized and unoxidized samples increases with increasing temperature; (2) emissivity of unoxidized sample doesn’t change with time. However, emissivity of oxidized sample increases due to the growing oxide layer with time; (3) a stronger effect of alloy composition is evident for oxidized samples.
For the examination of Multispectral radiation thermometry (MRT) with first-order linear emissivity model: (1) the best MRT examined wavelength range for unoxidized aluminum alloys is from 3 µm to 4 µm; (2) unoxidized samples provide better temperature prediction than oxidized samples; (3) if the emissivity model can well represent the real emissivity behaviors, the more accurate inferred temperature can be achieved.

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