二氧化鈦/氧化鈣/氧化釔陶瓷材料與熔融鈦界面反應

Abstract

本研究將不同比例的TiO2/CaO/Y2O3粉末相互混和，並以1500°C/30min的條件熱壓成陶瓷複合試片後，分別形成CaTiO3單體、Ca4Ti3O10單體以及三種不同比例Y2O3/Ca4Ti3O10複合材料，在1 atm 氬(Ar)保護氣氛下，與鈦進行1600°C/30min的高溫界面反應。本研究以X光繞射儀(XRD)和掃描式電子顯微鏡(ASEM)來分析界面微觀結構，並探討陶瓷材料與鈦高溫界面反應之生成機構。 本研究發現所有陶瓷試片與Ti高溫界面反應後，鈦側因氧和鈦的親和力很大，氧會往鈦側擴散，生成固溶氧的α-Ti，而釔及鈣幾乎不溶於鈦內，也不跟鈦反應。陶瓷側因為氧往鈦側擴散，靠近界面處的陶瓷氧化物會有缺氧現象。在三種不同比例的熱壓Y2O3/Ca4Ti3O10複合材料中，當Y2O3體積比例大於20%，Y2O3在試片內部有連通的networking現象；當Y2O3/Ca4Ti3O10複合材料試片和鈦進行界面反應時，遠離界面處原本連通的network Y2O3變成孤立的顆粒，且有粗化的現象。由於ambipolar diffusion效應，釔和氧會往界面擴散，而鈦往陶瓷擴散，在靠近界面處會形成一層Y2O3-x和α-Ti的反應層，其中，顆粒細小的Y2O3-x密集分布在α-Ti基地中，此反應層能夠阻擋氧往鈦側擴散，隨著Y2O3添加量的增加，這層反應層也隨之變厚。

Vanious proportions of TiO2 / CaO / Y2O3 powders were mixed and hot pressed at 1500°C for 30min. These hot-pressed specimens reacted with the commercially pure titanium at 1600°C for 30min in 1 atm argon atmosphere. The high temperature interfacial reactions were explored between each ceramic specimen and titanium metal. The interface microstructures were analyzed using an X-ray diffraction diffractometer (XRD) and an analytic scanning electron microscope (ASEM). When ceramic specimens reacted with titanium at 1600°C for 30min, the oxygen would be dissolved to the titanium to form α-Ti due to the great affinity between oxygen and titanium, resulting in the hypoxia phenomenon in the ceramic side near the interface. In the Ca4Ti3O10 specimens incorporating with Y2O3, Y2O3 formed network in the interior ceramic specimens with the volume ratio of Y2O3 was more than 20%. When the ceramic specimens reacted with titanium, Y2O3 would diffuse to the interface due to ambipolar diffusion, the titanium would diffuse to the ceramic side and the oxygen in Y2O3 would be dissolved to the titanium side, so that, a Y2O3-y and α-Ti layer was formed. With increasing in the amount of Y2O3, the layer would be thicker. The Y2O3 phase in the far away from interface would be coarser.