表面修饰纳米硼酸钙的制备及摩擦学性能

制备了表面修饰油酸的纳米硼酸钙添加剂,利用XRD、TEM和IR对其形貌及结构进行了表征,采用离心分离法考察了纳米硼酸钙在润滑油中的稳定性,在四球摩擦磨损试验机和SRV试验机上考察了油品的抗磨减摩性能,并用X射线光电子能谱(XPS)探讨了其润滑机理.结果表明:纳米硼酸钙添加剂具有良好的分散性、稳定性和抗磨减摩性能;沉积膜和反应膜的生成对抗磨减摩性能有决定作用.     

疏水性硼酸镧纳米棒的制备及其在菜籽油中的摩擦磨损性能(英文)

采用水热法合成油酸修饰的硼酸镧纳米棒(OA/La BO3·H2O),利用X射线衍射和扫描电镜等测试技术对其微观结构进行表征,并在四球摩擦试验机上考察其在菜籽油中的摩擦磨损性能。结果表明,所制备的OA/La BO3·H2O为直径约50 nm、长达500 nm的疏水性纳米棒。OA/La BO3·H2O能显著提高菜籽油的抗磨减摩性能;当OA/La BO3·H2O的添加量为1%(质量分数)时,菜籽油的抗磨减摩性能最佳。     

油幕电爆法对纳米铜粉分散性能的影响

利用自制的油幕电爆装置制备了纳米铜粉。以油酸作为分散剂对纳米铜粉进行分散,利用紫外-可见分光光度计(UV-Vis)、X射线衍射仪(XRD)和透射电镜(TEM)对不同制备方法获得的纳米铜粉在润滑油中的分散性能进行对比分析。结果表明:油幕电爆法制得的纳米铜粉分散性较好,产物纯度高,粒径分布范围10~50 nm,平均粒径为30 nm;当添加油酸的体积百分比为5%时,纳米铜粉在基础油中的吸光度最大,即其分散性最好。     

纳米α-Al2O3的制备及其悬浮液分散性的研究

以AlCl3.6H2O和NH4HCO3为原料,采用室温固相化学反应获得前驱体,1100℃煅烧1.5h,制备纳米α-Al2O3粉体,用XRD、TEM、BET及电子衍射等进行表征,通过对粒径和Zeta电位分析,研究了不同pH值、分散剂及其用量对纳米α-Al2O3粉体悬浮液分散性的影响。实验结果表明：产物为α-Al2O3,颗粒粒径为20nm~30nm,粒子尺寸分布较均匀,比表面积为66.32m2/g;悬浮液的分散性能受到pH值、分散剂种类及其加入量的影响,找到了制备高分散的、稳定的α-Al2O3悬浮液的最佳pH值及PEG10000的最佳添加量。     

添加剂对SrAl2O4:Eu,Dy纳米晶形貌和发光性能的影响

用溶胶-凝胶法制备纳米SrAl2O4Eu2+,Dy3+发光粉体,研究了添加剂硼酸的不同掺杂量对SrAl2O4Eu2+,Dy3+纳米晶形貌和发光性能的影响.结果表明,硼酸的加入有利于SrAl2O4相的生成并且改善了发光材料的发光性能;随着硼酸加入量增多,SrAl2O4Eu2+,Dy3+发光材料的发射光谱主峰出现蓝移现象,纳米晶的形貌从针状逐渐变成粒状.     

CO2固化纳米SiO2/甲阶碱性酚醛树脂的研究

考察用聚乙二醇修饰的纳米SiO2在树脂溶液中分散性;利用透射电镜、红外光谱研究了聚乙二醇(PEG)修饰的纳米SiO2表面性能及分散性的改进效果;并通过砂芯抗压强度来研究纳米SiO2的用量对CO2固化酚醛树脂粘结剂抗压强度的影响,结果表明:4%聚乙二醇修饰的纳米SiO2粒子在树脂溶液中分散性较好;纳米SiO2粒子表面羟基减少;添加量在0.3%时,粘结剂的抗压强度可以提高30%.     

二维纳米片状MoS2的制备及其作为润滑添加剂的减摩抗磨性能

目的 探究具有超薄结构的二维纳米片状MoS2的制备方法及其在发动机润滑油中的减摩抗磨性能。方法 以七钼酸铵和硫脲为反应前驱物,油胺为反应溶剂,采用原位表面法制备出表面修饰有油胺分子的二维纳米片状MoS2。利用透射电镜（TEM）、红外光谱分析仪（FT-IR）、X射线光电子能谱仪（XPS）表征纳米片状MoS2的形貌特征、表面状态及化学组成。采用球盘式摩擦磨损试验机对其作为润滑添加剂在发动机润滑油中的摩擦学性能进行考察,并通过三维共聚焦表面形貌仪、扫描电镜和X射线光电子能谱仪对磨痕进行分析。结果 所制备的具有超薄结构的二维纳米片状MoS2在发动机润滑油中具有良好的减摩和抗磨性能,当其添加量为3%时,摩擦系数降低27.1%,磨斑直径降低17.17%。在150 ℃高温下,使用纯发动机润滑油进行润滑时,摩擦初始阶段的摩擦系数高达0.5,出现润滑失效现象。然而,使用添加有3%二维纳米片状MoS2的润滑油进行润滑,150 ℃高温下的摩擦系数在整个实验过程中都比较平稳,磨损体积和最大磨痕深度为纯发动机润滑油润滑时的23.44%和28.53%。结论 在摩擦过程中,两摩擦表面处于边界润滑状态,所制备的二维纳米片状MoS2随润滑油进入摩擦接触区,发挥良好的润滑效果。特别是在高温下,当发动机润滑油润滑失效时,二维纳米片状MoS2在摩擦表面生成富含MoS2的摩擦化学反应膜填充修复磨损表面,起到润滑作用。     

含Bi2S3纳米有机流体的制备及表征

用萃取沉淀法直接制备了稳定的含纳米Bi2S3的有机流体.TEM,IR与XRD测试表明萃取剂对纳米Bi2S3粒子起到了良好的表面修饰作用.萃取剂Cyanex 302修饰的Bi2S3纳米微粒在汽油中的负载量可高达19.27 g·L-1.这种方法工艺简单,且大大提高了纳米粒子在有机相中的分散性,为纳米流体的制备与应用提供了新的思路.     

Y2O3：Eu^3＋纳米晶的制备及其光学性能研究

以NaOH,Y（NO3）3·6H2O和Eu（NO3）3．6H2O为前驱体,通过添加络合剂PEG-2000,采用水热法,成功地合成了Y2O3：Eu^3＋纳米棒和纳米管,并采用先进的测试手段对其结构和性能进行了表征与测试。探讨了Y2O3：Eu^3＋纳米棒和纳米管的生长机制,同时研究了Y2O3：Eu^3＋纳米晶的光致发光性能。研究结果表明,水热温度、反应时间、NaOH的添加量和PEG-2000对产物形貌有着非常重要的影响,所制备的材料具有Eu^3＋的特征红光发射,并在Eu^3＋的掺杂量为5％（摩尔分数）时样品发光最好。     

不同粒径的锑纳米颗粒在润滑油中的分散性与摩擦性能北大核心CSCD

以硅烷偶联剂KH-570为表面改性剂,采用机械球磨法制备了不同粒径的锑纳米颗粒。将不同粒径的锑纳米颗粒添加到900SN基础油中作为试验润滑油。通过测试润滑油的吸光度考察了锑纳米颗粒在润滑油中的分散稳定性;利用往复式摩擦实验研究锑纳米颗粒作为润滑油添加剂的摩擦学性能。研究结果表明:表面改性的锑纳米颗粒由于具有空间位阻效应,表现出良好的分散性。粒径越小,分散性越好;由于锑纳米颗粒可填补到磨损表面的微坑处,其在900SN润滑油中具有优良的减摩润滑效果。粒径越小,其对磨损表面的修复效果越好。当锑纳米颗粒粒径为40 nm时,其在试验润滑油中具有很好的分散性,并表现出优异的减摩抗磨性能。     

硼酸酯多功能添加剂合成及线切割工作液制备

以油酸、三乙醇胺、硼酸和聚乙二醇-400为原料合成一种具有较好水解稳定性、防锈性、润滑性和表面活性的硼酸酯多功能添加剂,通过正交试验确定添加剂合成的较优方案为:三乙醇胺5 g,硼酸2g,聚乙二醇-400 20 g,油酸10 g,采用一步法配制一种稳定透明的线切割工作液,并评定工作液的综合性能。结果表明:方法简单易行,成本低,配制的工作液具有良好的防锈性、消泡性、清洗性、润滑性与适当的电导率。     

7075铝合金微等离子体氧化硼酸盐体系电解液配方的优化

利用微等离子体氧化技术,在7075铝合金表面原位生成了陶瓷层.采用正交实验法确定了在硼酸盐体系中进行微等离子体氧化的最佳电解液配方,通过SEM及XRD分析了陶瓷层的形貌及相组成.结果表明:陶瓷层硬度可达到812HV0.1;陶瓷层表面形貌均匀,膜层致密,主要由γ-Al2O3组成.     

Effect of the milling conditions for nanocrystalline iron powders on their corrosion behavior in neutral electrolytes

The corrosion behavior of nanocrystalline iron powders obtained by milling in oxygen-containing organic media (isopropyl alcohol, acetic acid, oleic acid, and its solutions in heptane) was studied. The high corrosion resistances of iron powders obtained by mechanoactivation in oleic acid were associated with a protective surface layer formed by iron oxide and chemisorbed oleic acid or products of its partial degradation. Nanocrystalline iron-based systems that contain oxide phases without forming protective layers were less resistant to corrosion. Original Russian Text ? S.F. Lomayeva, A.V. Syugaev, S.M. Reshetnikov, A.S. Shuravin, O.M. Nemtsova, V.V. Aksenova, 2007, published in Zashchita Metallov, 2007, Vol. 43, No. 2, pp. 207–215.     

白云母 / CeO2 复合粉体的制备及其摩擦学性能研究

目的研究白云母/CeO2复合粉体在500SN基础油中的抗磨减摩性能和抗磨减摩机理。方法以白云母、硝酸铈、草酸为原料,通过球磨固相法制备不同配比的白云母/CeO2复合粉体,用油酸改性,采用XRD,SEM等对粉体的结构特征和表面形貌进行表征,并通过四球磨损实验考察不同油样的摩擦学性能。结果添加了白云母/CeO2和单一白云母的润滑油,摩擦学性能均比无添加的基础油优越。其中,添加了白云母/10%CeO2复合粉体的润滑油抗磨减摩性能最好,摩擦系数比基础油降低了10.7%,磨斑直径比基础油减少了24.4%。结论白云母/CeO2复合粉体有较好的抗磨减摩能力,对磨损表面有修复作用,合理配比的白云母/CeO2能有效提高基础油的抗磨减摩性能。     

表面活性剂对球磨法制备纳米Sb2O3粉末的影响

采用球磨法制备纳米Sb2O3粉末,研究表面活性剂对制备纳米Sb2O3的影响。采用X射线衍射仪、透射电子显微镜、红外光谱仪研究了球磨产物的物相组成、颗粒形貌以及平均粒径。研究结果表明表面活性剂对产物的Sb2O3含量、结晶度、粒径大小、形貌以及分散性具有显著地影响。当硬脂酸、辛基酚聚氧乙烯醚、聚丙烯酸钠作为表面活性剂时,球磨产物中Sb2O3的含量低于92%,颗粒大小不均匀,甚至出现团聚现象。当辛基酚聚氧乙烯醚与聚丙烯酸钠复配作为表面活性剂时,产物中Sb2O3含量为94%,颗粒形貌不规则。当聚丙烯酸钠与硬脂酸复配作为表面活性剂时,球磨产物中Sb2O3的含量达99%以上,分散性最好,粒径分布在10~20 nm之间,平均粒径15 nm左右。     

Oxidation process of lanthanum hexaboride ceramics

Oxidation process of lanthanum hexaboride (LAB6) ceramic powder was investigated. The LaB6 powder sampies were heated continually fTom room temperature to 1 473 K at a heating rate of 10 K/min by differential scanning calorimetry. The oxidation tests were conducted at different exposure temperatures. The phases and morphologies of the samples before and after exposure were analyzed by XRD and SEM. It was pointed out that before 1 273 K, LaB6 has high oxidation resistant ability, which was due to that the oxide layer hinders the oxygen diffusion fTom outer to the surface of LaB6 grains. The oxide layer was composed of the transition phases, which were composed of La203 and B2O3 formed fi‘om the initial oxidation; when the oxidation temperature exceeded 1 273 K, protective layer was destroyed due to the vaporization of liquid B2O3. Based on the results of X-ray diffraction analysis, oxidation process of LaB6 ceramicpowder can be described as follows: Before 1 273 K, lanthanum borate, La(BO2)3 was formed on the surface of samples,then lanthanum oxide (La2O3) and boron oxide (B2O3) were present on the surface of samples oxidized when the tempera-ture reached to 1 473 K.     

Corrosion of titanium in phosphoric acid at 250℃

Corrosion studies of a commercially pure titanium in phosphoric acid solutions at 250 ℃ were carried out by immersion test in an autoclave. At lower phosphoric acid concentration (0.1 mol/L), the corrosion was mild. At higher phosphoric concentration (1.0 mol/L) corrosion, a 25 μm-thick white corrosion products layer was formed on the samples after 24 h immersion. XRD analysis shows that the white layer consists mainly of titanium oxide phosphate hydrate (π-Ti2O(PO4)2·2H2O). The corrosion product shows the morphology of fiber bundles. A thermodynamic analysis of the formation of the corrosion product is presented.     

高密度煤油基磁性液体的制备及其性能表征

采用化学共沉淀法,通过改变Fe₃O₄纳米颗粒的生长温度、包覆环境pH、清洗、分散方式等工艺参数进行对比试验,得出Fe₃O₄纳米颗粒在生长阶段、包覆阶段、分散阶段的最佳参数条件,优化以往的制备工艺,使油酸包覆的磁性颗粒在煤油中的分散稳定性得到提高。通过XRD、TEM、VSM等对样品进行表征,并使用旋转流变仪对所制煤油基磁性液体的流变性能进行分析。结果表明,改性后的Fe₃O₄纳米颗粒平均粒径约为14nm,呈现较为规则的球形,饱和磁化强度为60 (A·m²)·kg^-1,可制备出质量分数可达60%的高密度煤油基磁性液体,与普通磁液相比,以此制备工艺得的高密度煤油基磁性液体在饱和磁化强度、抗氧化性等方面皆有较大提升,拥有更高的应用价值。     

Effect of surface pretreatment by acid pickling on the density of stannate conversion coatings formed on AZ91 D magnesium alloy

Hydrofluoric and hydrochloric acid solutions and a mixture of them were tested as pickling solutions for AZ91 D Mg alloy before application of stannate coatings. Optical microscopy and energy dispersive X-ray spectroscopy (EDX) of the alloy surface after the pickling process showed that the Mg-rich α phase dissolved preferentially rather than the Al-rich β phase in hydrochloric acid solution. On the other hand, in hydrofluoric acid solution, Mg dissolved in a form of pitting corrosion. Pickling pretreatment with a mixture of these acids at an optimal concentration and an optimal pickling time resulted in relatively uniform dissolution of the alloy surface. The potentiodynamic polarization technique was used to investigate the anodic behavior of the uncoated and coated magnesium alloy in borate buffer solution. The morphology of the coatings was observed using a scanning electron microscope (SEM) before and after corrosion tests. The experimental results showed that coating film density and corrosion resistance of stannate-coated samples prepared with pickling pretreatment were improved compared with those of the coated sample without pickling pretreatment.