Preparation, friction and wear properties of hydrophobic lanthanum borate nanorods in rapeseed oil

Oleic acid (denoted as OA) surface-caped lanthanum borate nanorods, abbreviated as OA/LaBO3·H2O, were prepared via hydrothermal method. The microstructures of the as-prepared OA/LaBO3·H2O nanorods were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The friction and wear properties of OA/LaBO3·H2O nanorods in rapeseed oil were evaluated with a four-ball tribo-tester. The results show that the as-prepared OA/LaBO3·H2O nanorods are hydrophobic and display nanorods morphology with uniform diameter of about 50 nm and length of up to 500 nm. In the meantime, OA/LaBO3·H2O nanorods can obviously improve the anti-wear and friction-reducing capacities of rapeseed oil, and the optimal anti-wear and friction-reducing properties of rapeseed oil were obtained at an OA/LaBO3·H2O content of 1% (mass fraction).

Friction and wear performances of borates and lanthanum chloride in water

The antiwear and friction-reducing performances of sodium borate, potassium borate and lanthanum chloride in water were evaluated on a four-ball friction tester. The topographies, element distribution and chemical characteristics of the worn surfaces were investigated by scanning electron microscope （SEM）, energy dispersion of X-ray （EDX） and X-ray photoelectron spectroscope （XPS）. The results indicated that sodium borate, potassium borate and lanthanum chloride increased extreme pressure, antiwear and friction-reducing capacities of water to a certain extent, of which potassium borate was the best candidate. Combination of lanthanum chloride with sodium borate and po- tassium borate respectively further improved antiwear and friction-reducing capacities. Scratches of worn surfaces lubricated with water containing borates and lanthanum chloride were less severe than those lubricated with water containing borates alone. A tribochemical film mainly composed of oxides of lanthanum, boron and iron reduced friction and wear for water lubricant formulated with both borates and lanthanum chloride.

Preparation and Tribological Behavior of Hydrophobic Lanthanum Borate Nanosheets in Rapeseed Oil

Oleic acid-capped lanthanum borate(abbreviated as OA/La BO_3·H_2O) nanosheets were prepared by the hydrothermal method. The microstructures of as-prepared OA/La BO_3·H_2O were characterized by means of SEM, TEM, EDS, FTIR and XRD, respectively. Moreover, the friction and wear properties of OA/La BO_3·H_2O as a lubricant additive in rapeseed oil were evaluated on a four-ball tribotester. The tribochemical characteristics of worn surfaces were investigated by SEM and XPS. The results showed that the hydrophobic OA/La BO_3·H_2O nanosheets exhibited their morphology with a diameter in the range of 100 nm to 300 nm and a thickness of about 25 nm, and displayed excellent dispersing stability in rapeseed oil. In the meantime, the rapeseed oil doped with OA/La BO_3·H_2O nanosheets markedly decreased the friction and wear of steel balls, and the optimal friction-reducing and antiwear ability of rapeseed oil was obtained at an OA/La BO_3·H_2O content of 1.0%. The outstanding tribological performance of OA/La BO_3·H_2O in rapeseed oil was attributed to the formation of a composite boundary lubrication film mainly composed of lubricious tribochemical species of B_2O_3, La_2O_3 and Fe_2O_3, and deposits of OA/La BO_3·H_2O nanosheets as well as the adsorbates of rapeseed oil on rubbed surfaces.

Synthesis and Crystal Structure of a Rubidium Lanthanum Borate Rb_3La_3(BO_3)_4

The title compound was obtained by the flux method and its structure was determined. It crystallizes in monoclinic, space group P2/c with a = 11.0024（17）, b = 9.2979（14）, c = 14.500（2） A, β = 110.879（2）°, V = 1385.9（4） A^3, Z = 4, Mr= 908.38, F（000） = 1592, p = 19.601 mm^-1, Dc = 4.353 g/cm^3, the final R = 0.0481 and wR = 0.1257 for 2532 observed reflections with I 〉 2σ（I）, The Rb3La3（BO3）4 structure can be viewed as a 3-dimensional scaffold-like framework constructed by La-O polyhedra and BO3 groups. Two Rb＋ ions locate in a channel along the a direction and the rest one in a cavity.

2-aminoethoxydiphenyl borate or lanthanum potentiates transient receptor potential-like channels in rat CA1 hippocampal neurons

Expression of transient receptor potential （TRP） channels is widespread with transcripts distributed throughout the brain. All TRP channel subunits are activated following phospholipase C activation and form cation-selective ion channels. Previous studies examining the existence of TRP channels in hippocampal CA1 pyramidal neurons were based on cultured neurons. Therefore, their relevance for living tissue remains unclear. In the present study, patch-clamp recordings were conducted from CA1 pyramidal neurons in hippocampal slices from 7-day-old rats. Whole-cell currents were obtained from CA1 hippocampal neurons with potentiation effects of 2-aminoethoxydiphenyl borate and lanthanum, revealing that recorded experimental currents were characteristic TRP-like channel currents. Identification of rat hippocampal mRNA transcripts of TRPC4, TRPC5, TRPV1, TRPV2, and TRPV3 channels further verified the expression of characteristic TRP-like channels on rat CA1 hippocampal neurons.

溶液燃烧法制备Nd^(3+)掺杂LaBO_(3)荧光粉

以La(NO_(3))_(3)·6H_(2)O、H_(3)BO_(3)为原料、C_(2)H_(5)NO_(2)为燃烧剂、Nd(NO_(3))_(3)·6H_(2)O为改性剂,通过溶液燃烧法合成Nd^(3+)掺杂LaBO_(3)荧光粉。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外-可见漫反射光谱(UV-Vis DRS)以及荧光光谱(PL)对产物进行表征分析。结果表明,制备的粉体均为正交晶系硼酸镧,在煅烧温度875℃、Nd^(3+)掺杂量3%的优化条件下制备的硼酸镧荧光粉发光性能最好,且其在紫外光区和可见光区均表现出良好的光吸收性能,发蓝绿色光,可广泛应用于激光照明和LED照明等领域。

Structure modeling of terbium doped strontium-lanthanum borate

Terbium doped strontium-lanthanum borate, Sr3La2（BO3）4：Tb （SLB）, was studied by semi-empirical computational ap- proaches using PM6 parametrization and the SPARKLE model for lanthanide（Ⅲ） （Ln（Ⅲ）） cations. The focus of interest was on structural aspects, e.g. the cell parameters and distribution of dopant ions between various sites as a function of dopant concentration. The cell linear dimensions were calculated to decrease linearly with increasing dopant molar concentration. SLB offered two sites for the dopant. Calculations predicted that one of these sites should be preferred by the Tb（Ⅲ） dopant. The optimized cell dimensions as well as the total energies differed for structures with dopant exclusively in site 1 or site 2. Computational predictions were tested against experimental results obtained for SLB synthesized by sol-gel method varying the dopant concentration. The agreement be- tween experimental and computational results was found sufficiently promising to continue the computational studies.

表面修饰纳米硼酸镧的制备及极压抗磨性能研究

用硼砂、硝酸镧、适当的修饰剂及修饰工艺,制备了表面修饰纳米硼酸镧极压抗磨添加剂,以四球实验评价了其极压抗磨性能.结果表明,纳米硼酸镧的最大无卡咬负荷(PB)比目前普遍使用的极压抗磨剂二烷基二硫代磷酸锌高8%,且磨痕直径较小.用X射线光电子能谱分析了蚀球磨斑表面的化学成分,在摩擦副表面发现了B、La、Fe等的氧化物,证明了此类添加剂能够在摩擦过程中不仅能生成以氧化硼、氧化铁等为主要成分的边界润滑膜,还可能形成含镧、硼的渗透层,这是此类添加剂具有良好抗磨减摩性能的主要原因.

纳米硼酸镧添加剂的摩擦学性能研究

通过对含纳米硼酸镧粒子添加剂润滑油的摩擦学性能试验研究 ,发现纳米硼酸镧添加剂能改善滑动摩擦副的摩擦学性能、抗胶合能力及润滑油的润滑性能 ,分析滑动摩擦副胶合失效后的表面形貌 ,结合失效后滑动摩擦副表面 XPS图谱 ,发现这是由于这种添加剂能在摩擦副表面形成吸附膜及聚合物膜 。

油溶性硼酸镧纳米微粒的制备及其在不同基础油中的摩擦学性能研究

采用表面修饰技术和沉淀法制备油胺修饰的硼酸镧(OAm-LaBO_3)纳米微粒,采用多种仪器设备分析OAm-LaF_3纳米微粒的结构、形貌及化学组成,评价OAm-LaBO_3纳米微粒在矿物油液体石蜡(LP)和合成酯类油癸二酸二异辛酯(DIOS)基础油中的减摩抗磨性能,推测其在LP和DIOS中的摩擦学作用机制。结果表明:OAm-LaBO_3在LP和DIOS基础油中均具有一定的减摩、抗磨性能,其中在LP中减摩性能显著,而在DIOS中抗磨性能突出。主要原因是LP和DIOS的极性不同,OAm-LaBO_3纳米微粒在摩擦过程中分解的有机小分子在摩擦表面吸附的难易程度不同,造成了减摩抗磨机制不同。

表面修饰硼酸镧纳米粒子的制备及摩擦学性能

以La(NO3)3.6H2O和Na2B4O7.10H2O为原料,添加硅烷偶联剂KH550,采用化学沉淀法制备出表面被修饰的硼酸镧纳米粒子;将制备的纳米颗粒按2%的比例加入纯基础油中制备成液固相分散体系,采用透射电子显微镜对体系的分散性进行表征,采用MMU-10G摩擦磨损试验机测试该分散体系对钢摩擦副的摩擦学性能。结果表明:该润滑油分散体系具有优异的抗磨性能以及良好的减摩效果,与纯基础油相比,在250 N、450 r/min转速下摩擦运行30 h的磨损率下降83%,摩擦因数下降30%。SEM、EDX分析表明,在摩擦过程中硼酸镧纳米材料参与了摩擦表面的成膜反应,起到了修复作用。

稀土元素摩擦催渗硼的研究

在研究油溶性二烷基二硫代磷酸镧（简称ＬａＤＤＰ）和有机硼酸酯（简称ＯＢ）的润滑性能和润滑机理过程中，发现这两种添加剂具有优异的协合润滑作用，且在适宜的摩擦条件下，稀土元素Ｌａ可促进Ｂ元素的摩擦扩散，并形成Ｌａ－Ｂ摩擦共渗层。提出了稀土元素对有机硼酸酯具有“摩擦催化裂化”的催渗机制。ＬａＤＤＰ在亚表面生成的Ｌａ－Ｂ摩擦共渗层使材料硬度增加和耐磨性增强。

纳米硼酸镧/聚苯乙烯复合材料制备及阻燃性能研究

采用原位聚合的方法将纳米硼酸镧与聚苯乙烯进行复合,制备纳米硼酸镧/聚苯乙烯复合材料。采用X射线衍射、红外光谱、扫描电子显微镜、热重分析和氧指数分析仪分析手段对产品的晶体组成、微观结构、阻燃性能和热稳定性进行表征。研究表明,纳米硼酸镧/聚苯乙烯复合材料具有表面均一、致密的表面结构,热稳定性明显提高,纳米硼酸镧添加量7%时,复合材料氧指数达到最大值32.5,聚苯乙烯阻燃性能显著增强。

PyDDP修饰纳米硼酸镧极压剂制备及性能研究

采用三步工艺合成了表面修饰剂二烷基二硫代磷酸吡啶(PyDDP),优化确定了PyDDP制备工艺条件,并利用红外光谱确认了其结构.将合成的PyDDP应用于硼酸镧表面修饰,并优化了合成的工艺参数.采用IR、TG-DTA、XRD等分析方法,对这3种表面修饰剂修饰的纳米微粒进行了表征.通过四球实验研究了所制备微粒的极压性能,并通过SEM、EDXA等方法对钢球表面的形貌、钢球表面存在的元素进行了分析.结果表明,以PyDDP为表面修饰剂获得了粒径约10 nm的PyDDP修饰的硼酸镧纳米微粒,其最大无卡咬负荷为745 N,并在蚀球表面发现了稀土元素.对PyDDP修饰硼酸镧结构与材料极压性能之间的关系进行了分析,指出稀土渗透层和稀土摩擦催渗硼的作用是该材料具有良好极压性能的主要原因.

水介质中硼酸盐-氯化镧的摩擦磨损性能研究

采用四球摩擦磨损试验机考察了硼酸钠、硼酸钾和氯化镧在水介质中的极压、抗磨和减摩性能,采用扫描电镜(SEM)、X射线能谱(EDX)、X射线光电子能谱(XPS)分析了磨斑表面形貌、主要元素的分布特征和化学状态。结果表明,硼酸钠、硼酸钾和氯化镧可一定程度地提高水的极压、抗磨和减摩性能,硼酸钾性能最优,硼酸盐与氯化镧复合后性能进一步改善。硼酸盐与氯化镧复合前摩擦表面擦伤严重,复合后擦伤明显减小,表面形成的La2O3,B2O3,Fe3O4和Fe2O3起到了良好的极压、抗磨和减摩作用。

Na_3La_2(BO_3)_3的晶体结构(英文)

以Na2 CO3 H3 BO3 NaF为助熔剂 ,使用顶部籽晶法生长出Na3 La2 (BO3 ) 3 透明单晶。测定了Na3 La2 (BO3 ) 3 的晶体结构 ,该晶体属正交晶系 ,空间群 :Amm2 (No .38) ,晶胞参数为a =0 .5 15 80 (10 )nm ,b =1.135 0 (2 )nm ,c =0 .732 30(15 )nm ,α=β=γ =90° ,V =0 .4 2 871(15 )nm3 ,密度 :4 .0 5 3g/cm3 。晶体结构中的硼氧基团是平面的BO3 基团 ,BO3 基团相互独立 ,且与Na(1)O6、Na(2 )O8、Na(3)O6和La(1)O9配位多面体连结形成三维网络骨架结构。讨论了Na3 La2(BO3 ) 3 的晶体结构与倍频效应的关系。

La_2O_3-H_3BO_3-C体系高温烧结过程的相组成研究

采用TG-DTA和XRD等分析手段对La2O3-H3BO3-C体系高温烧结过程中的相组成进行了研究。结果表明:在82~390℃之间,发生了H3BO3的三阶段脱水反应,第一阶段为82~153℃,生成了HBO2;第二阶段为153~222℃,生成了H2B4O7;第三阶段为287~390℃,生成了B2O3。在836~1 400℃时,主要是La2O3与B2O3反应生成LaB3O6和LaBO3。在1 450℃的高温下,La2O3、B2O3和C共同作用生成LaBO3和B4C,此时LaBO3相占主要地位,计算得到其晶胞参数为:a=7.955,b=8.160,c=6.499,属于单斜晶系。在1 500℃时,LaBO3和B4C反应生成LaB4、B和LaB6;LaB4和B进一步烧结生成LaB6,其生成率随烧结时间延长而增加,计算得到其晶胞参数为:a=4.156,属于立方晶系。

硼酸镧纳米棒的制备及其在植物油中的抗磨减摩性能

以Na2B4O7·10H2O和La(NO3)3·6H2O作原料,油酸作改性剂,采用水热法制备了硼酸镧纳米棒。利用X-衍射仪、FT-IR光谱仪、扫描电镜及能谱仪对其结构进行了表征,采用四球摩擦试验机考察了其在植物油中的抗磨减摩性能,利用扫描电镜观察了钢球表面磨斑的形貌,X射线光电子能谱测定了磨斑的元素组成。结果表明,硼酸镧呈纳米棒结构,其直径为50 nm、长达500 nm。硼酸镧纳米棒能显著提高植物油的抗磨、减摩性能,当添加剂的含量为1wt.%时,植物油的抗磨、减摩性能达到最佳。XPS分析结果表明,在钢球表面形成了一层含油酸的吸附膜和一层含Fe2O3、B2O3和La2O3等物质的润滑膜,这种润滑膜起到了良好的润滑作用。

铒/镱共掺硼酸钙镧晶体的生长和光谱性质(英文)

在CaO-Li_2O-B_2O_3助熔体系中,生长了掺铒和镱的硼酸钙镧(Er^(3+):Yb^(3+):La_2CaB_(10)O_(19),Er:Yb:LCB)晶体。Er:Yb:LCB晶体中Er^(3+),Yb^(3+)的分凝系数分别为0.50,0.25。X射线衍射分析表明:Er:Yb:LCB和LCB具有相同的晶体结构。Er:Yb:LCB晶体的熔点大约为1046℃。Er:Yb:LCB晶体的吸收光谱和荧光光谱的测试结果表明:与Er:LCB相比,Er:Yb:LCB晶体在970 nm的吸收系数显著提高,在1 531 nm的发射强度也显著增强,其荧光寿命为0.48 ms。

掺铬高温相硼酸镧钪的光谱研究

报道了掺铬高温相硼酸镧钪Cr3+:LaSc3(BO3)4(α CLSB)晶体的光谱特性。吸收光谱表明:CLSB晶体在可见光区有两个吸收带,吸收峰值分别位于457和654nm处,吸收系数均为19.07。室温荧光光谱则表现为一个源自于4T2→4A2能级跃迁的780～1120nm的宽带发射,其半峰宽为167nm,峰值为963nm。其荧光寿命为17μs。通过计算得出了铬离子所处的晶场强度Dq和拉卡参数B分别为1529和675cm-1,Dq B=2.26。研究结果表明:掺铬高温相硼酸镧钪有望成为一种新的可调谐激光晶体。