类水滑石CuNiAl的制备、表征及其催化性能的研究

采用水热法和尿素水解法首次合成了三元类水滑石CuNiAl(Cu+Ni/Al=3,Cu/Ni=5.0,3.0,1.0,0.33),将合成的类水滑石用于苯羟基化反应。采用X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、扫描电镜(SEM)和透射电镜(TEM)等手段对类水滑石进行表征,以CuNiAl31作为催化剂,考察了反应时间、反应温度、溶剂及溶剂用量、催化剂用量、n(benzene)/n(H_2O_2)对苯羟化反应的影响。结果表明:与CuNiAl11、CuNiAl21、CuNiAl13催化剂相比,CuNiAl31具有较高的反应活性,反应的最佳条件为:反应时间6h、反应温度65℃、15 ml吡啶作为溶剂、10mg催化剂、n(benzene)/n(H_2O_2)=3.0时,苯的转化率为7%,苯酚的选择性几乎为100%。

Ni含量对CuNiAl合金导电率及摩擦性能的影响

采用熔铸法制备CuNiAl合金,Cu含量为95wt%,Ni/Al原子比分别为1:3、1:2、1:1、2:1、3:1的CuNiAl合金。利用涡流电导仪和磨损试验机测量了不同状态合金的导电率。研究发现:CuNiAl合金随着Ni含量的逐渐增加,导电率减小,合金的黏着磨损减弱,磨粒磨损现象明显增加。

CuNiAl催化乙酰丙酸转移加氢制备γ-戊内酯的研究

通过共沉淀法成功合成CuNiAl-LDH前体,将其直接还原制备一系列CuNiAl催化剂,并考察其在催化乙酰丙酸转移加氢制备γ-戊内酯的反应性能,研究了活性组分、还原温度、供氢溶剂、反应温度和反应时间对催化性能的影响。结果表明,Cu组分加入后生成CuNi合金,显著提高了催化活性,且当n(Cu)∶n(Ni)∶n(Al)为1∶14∶5、还原温度为500℃时,催化性能最佳。以异丙醇为供氢溶剂,在170℃下反应120 min,乙酰丙酸的转化率和γ-戊内酯的选择性分别达到98.2%和83.1%。

Construction of CuNiAl-LDHs electrocatalyst with rich-Cu^(+)and—OH for highly selective reduction of CO_(2) to methanol

In this work,a high-performance CuNiAl-LDHs catalyst was innovatively synthesized for electrochemical carbon dioxide reduction(CO_(2)RR)of methanol(CH3OH)through the modulated synthesis of Cu-based layered double hydroxide(LDHs).It was found that the optimal CuNiAl-LDHs has superior CH3OH selectivity compared to CuAl-LDHs and CuMgAl-LDHs,with the Faraday efficiency(FE)of 76.4%for CH3OH generation at1.2 V.And their FE and current density(4.8 mA·cm^(2))remained stable during up to 24 h of electrolysis.Meanwhile,this study confirms the significant performance advantages of CuNiAlLDHs over their derived composite oxides.Series characterization further proves that the excellent catalytic performance of CuNiAl-LDHs is importantly associated with their richness in Cu+and hydroxyl group(-OH).The research expands the application fields of LDHs compounds.Meanwhile,the series of discoveries provide a new insight for the preparation of CH3OH by constructing CO_(2)RR.

CuNiAl合金时效析出过程及机理

研制了一种通过力学性能测试,X 射线边带分析及光学显微镜、透射电镜观察对高强度弹性合金 Cu—Ni—Al—Si—Cr—RE 时效析出动力学及其强化机理进行了研究。结果表明,该合金时效后具有调幅组织。时效初期主要是溶质原子偏聚并形成同期性排列的调幅组织。时效60min 以后调幅组织进入粗化阶段。合金的固溶时效与形变时效的析出过程不同,形变时效后得到胞状组织。该合金时效后除了弥散的调幅组织强化外,同时还有析出相强化。

In-situ study of martensitic transformation and nucleation, propagation of crack in CuNiAl shape memory alloy

The stress-induced martensitic transformation and its relation with crack nucleation and propagation in CuNiAl shape memory alloy were investigated through in-situ tensile tests by SEM and TEM.The results indicated that the stress concentration ahead of the crack tip could induce formation of stacking faults and different types of martensites.TEM observations showed that the martensites could transform from one type to another and even reversely to the parent during loading.The micro-cracks nucleated along the martensite/parent interface and intersection between two martensites.When the crack propagated a certain distance,the stress concentration ahead of the crack tip was large enough to result in formation of slip bands,and in this condition the microcrack nucleated along slip bands more easily.

用原子力显微镜研究形状记忆合金中裂纹形核和扩展

运用原子力显微镜（AFM）对形状记忆合金CuNiAl中裂纹扩展行为进行了观察.观察表明,拉伸时,裂纹尖端首先产生马氏体,纳米微裂纹择优沿马氏体相界面形核.但当外力较大,且裂纹扩展距离较长使裂尖应力集中足够大时,不但能诱发马氏体相变,也可出现滑移带. 一旦出现滑移带,裂纹也可沿马氏体或滑移带交替扩展.

新型铜镍铝合金热处理工艺研究

对新型铜镍铝合金进行热处理工艺试验,通过金相、扫描电镜和力学性能测试等方法,研究热处理制度对其组织和力学性能的影响。结果表明:合金经(890±10)℃保温30 min,出炉空冷到室温,其力学性能优良,组织以α相、KⅡ和KⅣ相为主。