粉末冶金材料科学与工程
粉末冶金材料科學與工程
분말야금재료과학여공정
POWDER METALLURGY MATERIALS SCIENCE AND ENGINEERING
2013年
3期
415-422
,共8页
侯佳倩%肖来荣%余宸旭%宋宇峰%王艳
侯佳倩%肖來榮%餘宸旭%宋宇峰%王豔
후가천%초래영%여신욱%송우봉%왕염
化学镀%Ni/TiH2复合粉末%形核长大机制%释氢性能
化學鍍%Ni/TiH2複閤粉末%形覈長大機製%釋氫性能
화학도%Ni/TiH2복합분말%형핵장대궤제%석경성능
electroless plating%Ni-coated TiH2composite powder%nucleation and growth mechanism%releasing hydrogen performance
采用化学镀法对 TiH2粉末表面镀 Ni,制备 Ni/TiH2复合粉末。通过 X 射线衍射(XRD)、扫描电镜(SEM)、能谱分析(EDS)及差热分析(DSC/TG)对 Ni/TiH2复合粉末进行表征,探索 Ni 镀层的生长及作用机理,建立镀层在粉末表面的生长模型。结果表明:施镀温度为85℃时 Ni/TiH2复合粉末表面 Ni 层包覆完整,镀层均匀致密,Ni层厚度约为1.0~2.0μm;施镀温度低于65℃时施镀几乎无法进行,而施镀温度高于95℃时,镀层很不均匀,且容易脱落;镀层的生长机制遵循奥斯特瓦尔德(Ostwald ripening)机制;与包覆前 TiH2粉末相比,Ni/TiH2复合粉末的释氢反应开始温度由450℃上升至540℃。包覆层可降低 TiH2粉末和熔融铝的温度梯度,从而推迟开始释氢的时间。
採用化學鍍法對 TiH2粉末錶麵鍍 Ni,製備 Ni/TiH2複閤粉末。通過 X 射線衍射(XRD)、掃描電鏡(SEM)、能譜分析(EDS)及差熱分析(DSC/TG)對 Ni/TiH2複閤粉末進行錶徵,探索 Ni 鍍層的生長及作用機理,建立鍍層在粉末錶麵的生長模型。結果錶明:施鍍溫度為85℃時 Ni/TiH2複閤粉末錶麵 Ni 層包覆完整,鍍層均勻緻密,Ni層厚度約為1.0~2.0μm;施鍍溫度低于65℃時施鍍幾乎無法進行,而施鍍溫度高于95℃時,鍍層很不均勻,且容易脫落;鍍層的生長機製遵循奧斯特瓦爾德(Ostwald ripening)機製;與包覆前 TiH2粉末相比,Ni/TiH2複閤粉末的釋氫反應開始溫度由450℃上升至540℃。包覆層可降低 TiH2粉末和鎔融鋁的溫度梯度,從而推遲開始釋氫的時間。
채용화학도법대 TiH2분말표면도 Ni,제비 Ni/TiH2복합분말。통과 X 사선연사(XRD)、소묘전경(SEM)、능보분석(EDS)급차열분석(DSC/TG)대 Ni/TiH2복합분말진행표정,탐색 Ni 도층적생장급작용궤리,건립도층재분말표면적생장모형。결과표명:시도온도위85℃시 Ni/TiH2복합분말표면 Ni 층포복완정,도층균균치밀,Ni층후도약위1.0~2.0μm;시도온도저우65℃시시도궤호무법진행,이시도온도고우95℃시,도층흔불균균,차용역탈락;도층적생장궤제준순오사특와이덕(Ostwald ripening)궤제;여포복전 TiH2분말상비,Ni/TiH2복합분말적석경반응개시온도유450℃상승지540℃。포복층가강저 TiH2분말화용융려적온도제도,종이추지개시석경적시간。
The Ni-coated TiH2 composite powder was prepared by electroless plating. The morphology, composition and hydrogen releasing performance were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS) and differential thermal analysis (DSC+TG). The plated Ni layer growth and action mechanism were explored preliminary, the growth model of the synthesis path on the powder surface was established. The results show that Ni coating layer with a average thickness of about 1.0~2.0 μm can be successfully prepared by electroless plating. When the plating temperature is 85 ℃, the coating is dense and uniform; while the temperature is over 95 ℃ or below 65 ℃, the plating is ineffective and the coating will be nonuniform and falling off easily. The growth mechanism of the coating follows the Ostwald ripening mechanism. Compared with the particles of TiH2 uncoated with Ni layers, the hydrogen releasing reaction temperature of Ni-coated TiH2 composite powder increases from 450 ℃ to 540 ℃. The coating can reduce the temperature gradient between TiH2 powder and molten aluminum and delays the hydrogen releasing time.