氧化釔/氧化鋯複和材料與鈦金屬高溫反應之介面微觀結構分析

Abstract

本實驗將ZrO2粉與Ti粉以1：1的比例混和後在400℃~1300℃進行熱分析，結果顯示反應在600℃~1000℃升溫過程有一寬的吸熱峰，為α-Ti + ZrO2→α-TiOx + ZrO2 的氧化還原反應，反應乃持續進行並非發生在特定溫度。O在3Y-ZrO2比純ZrO2有較快的擴散速率， 導致3Y-ZrO2與Ti的反應較為劇烈，而呈現較大的吸熱峰。另一方面，O的固溶造成α-Ti的安定化作用，提高α?βTi的相變化溫度，在操作溫度範圍內未觀察到α?βTi的相變化。本實驗另以熱壓法製備不同組成的ZrO2/Y2O3複合材料，使之與鈦金屬在1700℃進行界面反應，並利用SEM、XRD、EPMA及微硬度量測分析界面之微觀結構，結果顯示，Y2O3對Ti液的界面反應不顯著，陶瓷側反應層之厚度隨ZrO2含量的增加而增加，ZrO2體積含量高於30%的試片與Ti的反應急速加劇，而Ti金屬側之α相隨界面反應的程度而增加，Ti金屬側之微硬度曲線顯示，硬度值及硬化層厚度都隨熱壓試片ZrO2含量及反應時間增加。本實驗另以Y2O3塗佈於ZrO2陶心表面與鈦金屬在1700℃/10min/1 atm Ar進行界面反應，結果顯示，Y2O3塗層能有效地控制高溫Ti金屬與ZrO2陶心反應，達到阻擋Ti金屬與ZrO2反應的目的，對Ti金屬表面的硬度值影響最小，而石墨塗層並無法達到降低陶瓷與Ti液反應的目的。

In this study the powders mixed with Ti and ZrO2 of ratio 1:1 were subject to the Differential Thermal Analysis. The results showed a broad endothermic peak between temperature 600~1000℃ due to the redox reaction of α-Ti + ZrO2 →α-TiOx + ZrO2-x, which was continuously proceeding on heating. Since the oxygen had faster diffusion rate in 3Y- ZrO2 than in pure ZrO2, the reaction of 3Y-ZrO2 and Ti was more extensive. The solid solution of oxygen caused the stabilization of α-Ti, so that no endothermic peak of α→βTi transformation was observed in the DTA test range(450~1300℃). Hot pressed composites with various ratios of ZrO2 and Y2O3 were reacted with the Ti melt at 1700℃/10min in argon. Y2O3 had a best resistance to the titanium, while the thickness of reaction layer in the ceramic side increased with the content of ZrO2. When the content of ZrO2 is greater than 30%, the reaction between Ti and plates become more seriously. The interfacial reaction also enhanced the α phase in the Ti side. The hardness and the thickness of harden layer in the Ti side were both increased with the content of ZrO2 and reaction time. The reaction between Y2O3-coated ZrO2 specimen and Ti melt at 1700℃/10min in argon showed, the Y2O3 coating layer can effectively hinder the high temperature reaction between Ti and ZrO2.