复合聚全氟乙丙烯材料的介电及高频击穿性能研究

在聚全氟乙丙烯(FEP)中添加 TiO_2和 Al_2O_3,通过热压成型的方法制备了 FEP/TiO_2复合材料和 FEP/Al_2O_3复合材料,研究了氧化物添加量对复合材料介电常数、介电损耗和高频击穿性能的影响。结果表明,随氧化物含量的增加,复合材料的介电常数和介电损耗均增加;在同一添加量下,TiO_2对复合体系的介电性能影响较大。FEP/TiO_2复合材料的高频击穿性能随 TiO_2含量的增加而下降,在 TiO_2含量为4.0%(质量分数,下同)时,复合材料的损伤阈值已降为 FEP 材料损伤阈值的48.9 %。而 FEP/Al_2O_3复合材料的高频击穿性能随 Al_2O_3含量的增加而升高,当 Al_2O_3含量为1.2%时,复合材料的损伤阈值已增大到 FEP 材料损伤阈值的2倍,达到313 J/m~2。     

ZrO2添加剂对β“—Al2O3性能的影响

研究了氧化锆添加剂对β”－Ａｌ２Ｏ３陶瓷的显微结构和性能的影响。实验结果表明，添加１０％（按体积计）ＺｒＯ２可以大大改善β”－Ａｌ２Ｏ３陶瓷的显微结构，并使其强度有显著提高，与此同时，β”－Ａｌ２Ｏ３的电导率下降不多。     

Al2O3—TiB2陶瓷刀具材料的高温氧化及其对刀具耐磨性能的影响

研究了Ａｌ２Ｏ３－ＴｉＢ２陶瓷刀具材料在１０００℃下的氧化行为，用ＸＲＤ、ＳＥＭ分析了氧化后的相组成及显微结构。结果表明：Ａｌ２Ｏ３－ＴｉＢ２陶瓷材料在１０００℃空气中氧化增重符合抛物线规律；随ＴｉＢ２含量的增加，该材料的抗氧化能力下降。     

SiO2微粉与Al2O3开始反应温度度的研究

对ＳｉＯ２微粉和Ａｌ２Ｏ３细粉所制的试样在不同温度下煅烧后的强度，Ｘ－射线定量分析，红外光谱进行了研究，结果表明，它们之间反应开始于７００℃。     

前驱体热解法制备Al2O3的物相转变及其合成

本文着重考查了Al2O3的前驱体一碳酸铝铵沉淀的形成过程及煅烧过程物相变化，发现可通过调节反应条件和加入合适的表面活性剂，来控制碳酸铝铵晶核的形成及晶体的生长速度，有效地阻止了Al2O3的团聚，并在温度1150摄氏度下制备出分散的Al2O3，其平均粒径为－2um，比表面为－3m^2/g。     

Surface modification of spherical LiNi1/3Co 1/3 Mn1/3O2 with Al2O3 using heterogeneous nucleation process

To improve the cycle stability at high voltage and high charge/discharge rate, spherical LiNi1/3Co1/3Mn1/3O2 was coated with Al2O3 by using heterogeneous nucleation process, and the physical and electrochemical properties were studied. The SEM images show that there is a uniform coating on the modified spherical LiNi1/3Co1/3Mn1/3O2. The electrochemical tests indicate that the properties of LiNi1/3Co1/3Mn1/3O2 coated with 0.5% aluminum oxide are the best. The initial capacities are 150 and 173 mA.h/g at the rate of I C in the voltage range of 2.7-4.3 V and 2.7-4.6 V, respectively, and the discharge capacities maintain about 99% and 85% after 30 cycles, respectively. While those of the bare LiNi1/3Co1/3Mn1/3O2 are only 90% and 75%, respectively. The CV tests of LiNi1/3Co1/3Mn1/3O2 show that Al203-coating can restrain the oxide-reduction peak currents fading during the charge/discharge course.     

Formation of CaO-TiO2-MgO-Al2O3 dual phase inclusion in Ti stabilized stainless steel

The formation of CaO-TiO2-MgO-Al2O3 dual phase inclusion in 321 stainless steel was investigated in the laboratory. The result indicated that the condition for the formation of CaO-TiO2-MgO-Al2O3 in 321 steel is [Ca]〉0.001wt%, [Ti]〉0.1wt%, and [A1]〉0.01wt%. The mechanism is the following： Al2O3 inclusion turns into CaO-Al2O3 after Ca-Si wire is fed into the molten steel; [Mg] is then obtained by reducing MgO in slag or crucible wall by [Al] and [Ti]; finally CaO-Al2O3 inclusion is changed into CaO-TiO2-MgO-Al2O3 by the reaction with [Mg], [Ti], and [O] in the molten steel simultaneously.     

掺杂纳米Al2O3的石墨/Cu基复合材料性能研究

利用均相沉淀法制备了含石墨粉的纳米Al2O3，采用模压成型法制备了含有纳米Al2O3的铜质石墨复合材料，并研究了此复合材料的性能与纳米Al2O3质量分数的关系．根据实验结果分析了实验现象的原因，并由此得出：当纳米Al2O3的质量分数为4％时，其铜质石墨复合材料性能最佳。     

KNO3在γ—Al2O3上分解及表面碱位形成的研究

用浸渍法制备ＫＮＯ３／Ａｌ２Ｏ３样品，热重－差热（ＴＧ－ＤＴＡ）结果显示ＫＮＯ３分解经两个过程，分别对应８７３Ｋ和吸热峰。拉曼光谱显示９７３Ｋ抽空的样品ＫＮＯ３已完全分解成Ｋ２Ｏ。微量吸附量热结果表明９７３Ｋ抽空的样品碱性比纯ＭｇＯ的还强，这种强碱性应为ＫＮＯ３完全分解成Ｋ２Ｏ物种所致，而γ－Ａｌ２Ｏ３载体的存在可增强ＫＮＯ３的分解。     

铬天青S分光光度法测定炉渣中三氧化二铝含量的不确定度评定

对铬天青S分光光度法测定高炉渣中三氧化二铝含量的不确定度的产生原因进行了分析,并对一个高炉渣中三氧化二铝含量测定结果的不确定度进行了评定.