本研究以Ti-6Al-4V(Ti64)為底材，於720 °C ~ 820 °C進行120秒到600秒的熱浸純鋁。結果顯示，Ti64於鋁湯中和鋁形成TiAl3，TiAl3層之厚度不隨熱浸溫度與時間而有顯著變化。鋁化形態為1 µm的TiAl3層，外側為含細微TiAl3顆粒之純鋁層。由於鈦與液態鋁形成TiAl3後體積大幅縮小，因此TiAl3層中的TiAl3顆粒(晶粒)均為Al所包覆。當熱浸後之Ti64再升溫到高於鋁熔點以上，晶粒間Al(l)快速沿晶與Ti64底材反應，且因體積收縮使鋁化層呈現多孔之形貌。此多孔鋁化層之形貌於單純高溫氧化環境，因TiAl3有很好的抗氧化性，雖然是孔洞形貌，但仍僅有少量的氧化增重。但在Na2SO4-V2O5熱腐蝕，熔融腐蝕鹽沿孔洞滲入，快速破壞鋁化層侵蝕合金底材。若Ti64熱浸鋁後先於鋁熔點溫度以下持溫擴散，較緩慢的固體擴散以及較小的體積收縮，可以獲得緻密的TiAl3層，大幅提升Ti64的抗熱腐蝕性。

In this study, Ti-6Al-4V (Ti64) was used as the substrate, and hot-dipped aluminizing was conducted at 720 °C~820 °C for 120 seconds to 600 seconds. The results show that Ti64 react with molten aluminum and form TiAl3, However the thickness of the TiAl3 layer does not change significantly with hot-dip temperature and time. The aluminized morphology of the TiAl3 is 1 µm layer, and the outer side is a pure aluminum layer containing fine TiAl3 particles. Since Ti react with Al(l) and form TiAl3, the volume is greatly reduced, so the TiAl3 particles (grains) in the TiAl3 layer are all surrounded with Al. When hot-dipped Ti64 be heated up to higher than the melting point of aluminum, the intergranular Al(l) reacts with Ti64 substrate rapidly along the grains, and the aluminized layer appears porous due to volume shrinkage. The morphology of this porous aluminized layer is in a simple high-temperature oxidation environment. Because TiAl3 has good oxidation resistance, although it is a pore morphology, there is still only a small amount of oxidized weight gain. However, in Na2SO4-V2O5 hot corrosion, molten corrosion salt penetrates along the voids, quickly destroying the aluminized layer and eroding the alloy substrate. If Ti64 is hot-dip aluminum and then diffuses at a temperature below the melting point of aluminum, slower solid diffusion and smaller volume shrinkage can produce a more compact TiAl3 layer, which greatly improves the hot corrosion resistance of Ti64.

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