Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/9742
標題: 電解沉積氧化鋯及冷加工對AISI430不銹鋼氫擴散之影響
The Study of Electrolytic Deposition of ZrO2 Thin Films and Cold
作者: 顏瑞祥
Yen, Rei hsiang
關鍵字: hydrogen diffusion;氫擴散;electrolytic deposition;ZrO2;cold work;430 stainless steel;電解沉積;氧化鋯;冷加工;430 不銹鋼
出版社: 材料工程學研究所
摘要: 
本研究以AISI 430 不銹鋼為材料,探討經電解沈積形成氧化鋯薄膜、冷
溫加工、及再結晶退火等不同處理條件下,氧化物層及微結構變化對氫擴
散之影響。由Devanathan's dual-cell對材料施以陰極充氫,進行擴散遲
滯時間(time-lag)、穿透時間(breakthrough time)、擴散係數和表面氫
濃度之量測,並以掃瞄式電子顯微鏡(SEM)、光學顯微鏡(OM)、X-ray繞射
儀(XRD)加以分析。結果發現定電壓電解沈積氧化鋯於430不銹鋼上,隨著
沈積時間的增長,氧化鋯薄膜越厚,但擴散遲滯時間()並沒有隨之變長。
過長的沈積時間,氧化鋯會因在燒結時產生裂縫,使得氫越容易擴散至基
材內部;只有在適當的沈積時間可得一均勻且無裂縫之氧化鋯薄膜,其阻
止氫擴散的效果甚至較加熱成長氧化膜於430不銹鋼上來的好。經由數學
模式的分析,發現阻止氫脆的效果是由於氫在氧化鋯的擴散係數非常低所
致。隨著冷加工程度的增加,差排密度提高。差排的存在會對擴散中的氫
原子進行捕捉,限制了氫原子的移動,且氫原子的捕捉效應(trapping
effect)會使有效擴散係數值降低,在50%冷加工尤為明顯。將冷加工50%
之430試片於800℃退火,結果發現,退火後的晶粒再結晶成長,晶界比例
變小,但擴散係數卻隨著退火時間增長而越來越大;退火120 min甚至達
到未退火的65倍。這是因為此時的擴散路徑逐漸被(110)擇優取向加速
的晶格擴散效應所取代。隨著退火時間的增長,晶粒更大,優選方向的趨
勢更顯著,氫擴散速率更快。

Through electrolytic deposition ZrO2, cold work, and
recrystallization annealing, the effects of oxide films and
microstructures on the hydrogen diffusion of the AISI 430
stainless steel had been investigated. The time-lag (),
breakthrough time (), diffusivity and sublayer concentration
were derived by hydrogen diffusion tests. The morphology and
microstructures were analyzed by scanning electron microscopy
(SEM), optical microscopy (OM), and X-ray diffractometer (XRD),
respectively.It was found that thickness of ZrO2 coating on 430
stainless steel is increased with increasing time, while the
time-lag was not. Because of the longer deposition time, the
micro-crack would be found during drying or sintering, which
made hydrogen atoms easier diffuse into the 430 stainless steel
substrate. Only for a proper coating time, a uniform ZrO2 film
could be obtained. Its effect of preventing the hydrogen
diffusion was even better than thermally grown oxide films on
430 stainless steel. By the analysis of a mathematical model,
the retarding effect on hydrogen entry of electrolytic
deposition ZrO2 on AISI 430 stainless steel is mainly because of
a very low diffusivity .The dislocation density was increased
with the increasing of cold work degree, so was the dislocations
trapping effect which would decrease the effective diffusivity,
especially in 50% cold work. After annealed at 1073K, the
grain size of 50% cold work 430 stainless steel was increased,
and the ratio of grain boundary to lattice was decreased with
increasing time. XRD showed the highest ratio of (110) preferred
orientation and the hydrogen permeation tests showed the
shortest time-lag for 120 min annealing. It was considered that
a quicker diffusion path such as the lattice diffusion of (110)
preferred orientation replaced that of random orientation, and
the grain boundary as a barrier for lattice diffusion was
further reduced.
URI: http://hdl.handle.net/11455/9742
Appears in Collections:材料科學與工程學系

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