Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/10052
標題: The Role of Oxygen in the Reactions between Titanium and Nitrogen
氧對鈦與氮氣反應之影響
作者: 江柏風
Jiang, Bor-Feng
關鍵字: oxygen;氧;titanium;nitrogen;oxygen partial pressure;reaction;鈦;氮;氧分壓;反應
出版社: 材料工程學研究所
摘要: 
鈦在氮氣中高溫反應時,由於即使使用高純度(99.999%)的氮氣,其中仍存在著少許的氧,因此除了氮會與鈦產生反應之外,氮氣中少許的氧也可能與鈦產生反應。以高純度的氮氣而言,其量測的氧分壓值約為10^-5 atm,但在600℃,當鈦坯置於氮氣中,會將氧分壓拉低至10^-23 atm,在600∼900℃的升溫階段,會使氧分壓則從10^-23升高至10^-15 atm,其氧分壓隨溫度增加而增加,若將材料改為鈦片,在600℃時,氧分壓並未被降低下來,但在600∼800℃的升溫階段,氧分壓則從10^-5 atm降低至10^-15 atm,在800∼900℃的升溫階段,氧分壓則從10^-15 atm緩慢地升高至10^-14 atm。
經沿著垂直試片表面的方向,一層層磨除,X光繞射的結果顯示,鈦坯內部形成TiNx,而外部生成穩定的TiO2,隨著溫度的增加,鈦坯內部的鈦氮化物由TiN0.3逐漸相變化為Ti2N、TiN,而外部的TiO2厚度也隨著持溫時間的增加而增加,因此在600∼900℃的升溫階段,氧分壓隨著溫度升高而升高,應是鈦坯迅速形成氮化物後,可能是因為此時氧化速率變快的緣故,使得氧溶解在鈦氮化物中的量減少,並且又由於氧化所造成氧分壓降低的程度不大,所以氧分壓隨著溫度升高而逐漸地升高。鈦片經X光繞射的結果顯示,內部仍為大量的Ti,但外部則生成穩定的TiO2,隨著溫度的增加,TiO2厚度也隨之增加,因此氧分壓大致隨溫度升高而降低,應是氧擴散溶解到鈦片的速率,隨著溫度增加而增加的緣故。

When titanium is placed in nitrogen at high temperature, the nitridation as well as the oxidation of titanium would occur. The mean reason is that even nitrogen with high purity (99.999%) still exists a small amount of oxygen. The measured oxygen partial pressure in the nitrogen is about 10^-5 atm. When titanium pellets were placed in the nitrogen, the oxygen partial pressure would decrease from 10^-5 atm to 10^-23 atm at 600℃. Moreover, the oxygen partial pressure would increase from 10^-23 atm to 10^-15 atm when increasing temperature from 600 to 900℃. Nevertheless when titanium plates were placed in the nitogen, the oxygen partial pressure would not be decreased but reamained at 10^-5 atm. The oxygen partial pressure would decrease from 10^-5 atm to 10^-15 atm when increasing temperature from 600 to 800℃. Then the oxygen partial pressure would increase from 10^-15 atm to 10^-14 atm at 900℃.
After grinding the titanium samples layer by layer, the X-ray diffraction results show that the internal part of titanium pellets constained mainly TiNx but the external part of titanium pellets contained mostly TiO2. When increasing temperature, TiN0.3 phase existing in the internal part of titanium pellets started to transform gradually to Ti2N and TiN. When the reaction time is increased, the thickness of TiO2 in the external part of titanium pellets would also increase. The oxygen partial pressure changes are closely related to the changes in the microstructure. The nitrides would dissolve oxygen and the oxidation of the nitrides required oxygen. Both processes consume oxygen in the nitrogen and the former process consumed more oxygen. These two processes are responsible for the oxygen partial pressure changes. The X-ray diffraction results show that the internal part of titanium plates existed a great amount of titanium and the external part of titanium plates contained mostly TiO2. The thickness of TiO2 increased with temperature. The diffusion and the dissolution of oxygen in titanium are rate-limiting processes and are responsible for oxygen partial pressure change.
URI: http://hdl.handle.net/11455/10052
Appears in Collections:材料科學與工程學系

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