氧化鋯與鈦金屬介面反應之微觀結構分析

Abstract

本實驗利用TEM/EDS、SEM/EDS、XRD來鑑定ZrO2與Ti在1100℃~1550℃擴散反應後之介面微觀結構。結果顯示當溫度高於1300℃時，由於鈦與氧的親和力大，使得ZrO2還原成ZrO2-x，而α-Zr(O)會從陶瓷側的缺氧氧化鋯(ZrO2-x)中析出，在1300℃所形成之缺氧氧化鋯(ZrO2-x)經TEM鑑定為tetragonal結構。當溫度達1550℃時，在冷卻過程中，氧化鋯側立方晶相缺氧氧化鋯晶粒內有透鏡狀結構之正方晶相氧化鋯產生。在鈦側，鈦金屬在1550℃時可固溶大量的Zr及O元素，以α-Ti(Zr, O) 與/或 β-Ti(Zr, O)相存在，但因β-Ti 固溶入大量的Zr及O導致β-Ti (bcc)會完全轉變成β′-Ti (orthorhombic)，冷卻時在其晶界間會有α-Ti析出。在溫度高於1100℃時，在介面處會有orthorhombic 結構的Ti2ZrO從hexagonal結構的α-Ti(Zr,O)中析出；α-Ti(Zr, O)與Ti2ZrO之間方位關係為[0001]α-Ti //[001]Ti2ZrO。

Hot pressed 3 mol%Y2O3-ZrO2 was reacted with titanium at temperatures ranging from 1100 to 1550℃. The microstructure of the reaction interface was characterized by TEM/EDS, SEM/EDS, and XRD. The results showed that because of the chemical affinity between titanium and oxygen, ZrO2 was reduced into ZrO2-x due to the interfacial reaction. α-Zr(O) was precipitated from ZrO2-x in the ceramic side at the temperature above 1300℃. The oxygen deficient zirconia was identified to be a tetragonal structure by TEM below 1300℃. At 1550℃, the lenticular t-ZrO2-x was produced from c- ZrO2-x during cooling. In the metal side,α-Ti(Zr, O) and β-Ti(Zr, O) coexist at 1550℃. β-Ti(bcc) was transformed to β´-Ti(orthorhombic) due to the dissolution of a large amount of Zr and O. The lamellae structure of α-Ti(Zr, O) was precipitated at the grain boundaries of β´-Ti during cooling. Ti2ZrO was precipitated from α-Ti(Zr, O) at the interface above 1100℃. α-Ti(Zr, O) and Ti2ZrO were identified to be hexagonal and orthorhombic, respectively, with the orientation relationship of [0001] α-Ti //[001]Ti2ZrO.