Study on RE-Al-Zr-C-N Coating by X-ray Photoelectron Spectroscopy

Ｔｈｅｉｎｖｅｓｔｉｇａｔｉｏｎｓｏｆｃｈｅｍｉｃａｌｔｈｅｒｍａｌｄｉｆｆｕｓｉｏｎｏｆｒａｒｅｅａｒｔｈｓｏｎｔｈｅｓｕｒｆａｃｅｏｆｍｅｔａｌｓａｎｄａｌｌｏｙｓｈａｖｅｂｅｅｎｇｒｅａｔｌｙｄｅｖｅｌｏｐｅｄｆｏｒｔｗｅｎｔｙｙｅａｒｓ .Ｔｈｅｅｘｐｅｒｉｍｅｎｔａｌｒｅｓｕｌｔｓｐｒｏｖｅｄｔｈａｔｒａｒｅｅａｒｔｈｓｃｏｕｌｄｂｅｐｅｒｍｅａｔｅｄｉｎｔｏｔｈｅｓｕｒｆａｃｅｏｆｍｅｔａｌｓａｎｄａｌｌｏｙｓ ,ａｎｄｔｈｅｙｇａｔｈｅｒｅｄａｎｄｄｉｆｆｕｓｅｄａｔｇｒａｉｎｂｏｕｎ…     

稀土对WC－8Ni硬质合金性能影响的研究

研究了添加微量稀土氧化物对ＷＣ－８Ｎｉ硬质合金物理机械性能的影响。在用Ｘ射线。射、扫描电镜及透射电镜等手段对含稀土ＷＣ－８Ｎｉ合金进行显微结构分析的基础上，探讨了稀土在合金中的分布状态、对组织结构的影响及其强化机理。井指出，通过添加微量稀土氧化物，可使ＷＣ－８Ｎｉ硬质合金的物理机械性能接近和达到ＹＧ８的水平。     

EDTA滴定法测定稀土铝中间合金中稀土总量

准确测定稀土铝中间合金中稀土总量,对于有效控制稀土铝中间合金的生产技术和产品质量具有重要意义。用400g/L氢氧化钠溶液溶解试样,此时,稀土与氢氧化钠反应生成氢氧化稀土沉淀,而铝与氢氧化钠反应后以偏铝酸根的形式留在了试液中,过滤,实现了铝与稀土元素的分离;用盐酸溶解沉淀,加入氢氟酸,此时稀土和氢氟酸反应生成氟化稀土沉淀,而铁与氢氟酸反应形成络合物留在溶液中,过滤,实现了干扰元素铁与稀土元素的分离;加入盐酸和高氯酸溶解沉淀,用抗坏血酸还原残留铁(III),乙酰丙酮溶液掩蔽残留的少量干扰元素铝,控制pH 5.5,以二甲酚橙作指示剂,用EDTA标准溶液滴定至溶液由红紫色变为亮黄色即为终点,建立了EDTA滴定法测定稀土铝中间合金中稀土总量的方法。将实验方法用于稀土铝中间合金(镧铝、钐铝、铒铝、钇铝)试样中稀土总量的测定,并在试样中分别加入不同量的于950℃马弗炉中灼烧过的高纯氧化镧、高纯氧化钐、高纯氧化铒和高纯氧化钇试剂进行加标回收试验,结果的相对标准偏差(RSD,n=11)不大于0.30%,加标回收率为99.6%~100.4%。选取镧铝、钐铝试样,按照实验方法测定其中稀土总量,并采用国标GB/T 31966—2015中的草酸盐重量法进行方法比对试验,测定结果基本一致。     

重量法测定镧镍合金中稀土总量

准确测定镧镍合金中稀土总量,对于有效控制镧镍合金的生产技术和产品质量具有重要意义。因镧镍合金中镍含量在50%(质量分数,下同)以上,其他共存元素中钴约10%、锰约5%,故很难通过单一分离方式彻底分离共存元素。实验依次采用氟化分离、氨水分离、草酸沉淀方式分离共存元素,进而对镧镍合金中稀土总量的测定进行探讨。试样经盐酸和硝酸溶解,采用氢氟酸、氨水、草酸沉淀稀土,逐一分离去除干扰元素,在pH值为1.8~2.0条件下,稀土元素沉淀为草酸稀土,950℃灼烧草酸稀土生成稀土氧化物(不含氧化钍),再以镧对氧化镧换算成金属稀土总量。盐酸-硝酸能够完全平稳溶解试样,且测定结果(30.42%)与参考值(30.43%)相符;采用氟化分离、氨水分离、草酸沉淀的分离方式很好地去除了镍、钴、锰、铝、铜、铁等非稀土杂质;按照实验方法测定镧镍合金样品中稀土总量,结果的相对标准偏差(RSD,n=11)均小于0.50%;加标回收率为 99%~101%。按照实验方法选取两家实验室对镧镍合金中稀土总量进行测定数据比对,结果基本一致并与参考值相符。     

重量法测定镧镍合金中稀土总量

准确测定镧镍合金中稀土总量,对于有效控制镧镍合金的生产技术和产品质量具有重要意义。因镧镍合金中镍含量在50%(质量分数,下同)以上,其他共存元素中钴约10%、锰约5%,故很难通过单一分离方式彻底分离共存元素。实验依次采用氟化分离、氨水分离、草酸沉淀方式分离共存元素,进而对镧镍合金中稀土总量的测定进行探讨。试样经盐酸和硝酸溶解,采用氢氟酸、氨水、草酸沉淀稀土,逐一分离去除干扰元素,在pH值为1.8~2.0条件下,稀土元素沉淀为草酸稀土,950℃灼烧草酸稀土生成稀土氧化物(不含氧化钍),再以镧对氧化镧换算成金属稀土总量。盐酸-硝酸能够完全平稳溶解试样,且测定结果(30.42%)与参考值(30.43%)相符;采用氟化分离、氨水分离、草酸沉淀的分离方式很好地去除了镍、钴、锰、铝、铜、铁等非稀土杂质;按照实验方法测定镧镍合金样品中稀土总量,结果的相对标准偏差(RSD,n=11)均小于0.50%;加标回收率为 99%~101%。按照实验方法选取两家实验室对镧镍合金中稀土总量进行测定数据比对,结果基本一致并与参考值相符。     

X荧光光谱法分析稀土铝铁合金中稀土、铝、硅、磷

介绍了硼酸镶边垫底粉末压片X荧光光谱法分析稀土铝铁合金中稀土、硅、铝、磷等元素的方法.     

三溴偶氮胂分光光度法测定镁合金中稀土总量

采用三溴偶氮胂分光光度法,以盐酸分解含单一或混合轻稀土镧、铈、镨、钕和中稀土钐、钆的镁基合金,25 mL溶液中0.6 g/L显色剂用量为3～8 mL,盐酸浓度为0.5～1.0 mol/L,在640 nm波长下测定了镁基合金中的稀土总量。基体镁对测定无干扰。轻、中稀土总量的质量浓度在0.2～0.8 μg/mL范围内与吸光度呈线性,相关系数R²在0.999以上,表观摩尔吸光系数ε_RE为(1.10～1.19)×10⁵ L·mol^-1·cm^-1。按照实验方法测定各类稀土镁合金样品中稀土总量,结果的相对标准偏差(RSD,n=6)不超过1.6%;并与电感耦合等离子体原子发射光谱法(ICP-AES)测定结果相一致。     

球磨时间对掺杂Ce(SO4)2的NaAlH4吸放氢性能的影响

采用球磨的方式在NaAlH4中掺入稀土催化剂Ce(SO4)2,通过X射线衍射仪(XRD)、扫描电镜(SEM)及PCT(pressure content temperature)测试仪研究了球磨时间对NaAlH4的相结构和吸放氢性能的影响.结果表明,经过不同时间球磨后,掺杂Ce( SO4)2的NaAlH4样品仍由NaAlH4相和Ce(SO4)2相组成,球磨没有改变样品的相组成.但是样品的放氢温度均降低,并在球磨6h时达到最大程度,放氢温度下降了40℃.吸氢后的样品中均存在Al,Na3AlH6和掺杂相Ce(SO4)2,球磨3和6h的样品还存在NaAl4相,说明第二步吸氢反应的程度较大.球磨6h的样品的吸氢性能最好,吸氢量达到3.598％(质量分数).球磨时间越长,颗粒越细小,颗粒细化是提高样品吸放氢性能的主要原因.但球磨时间过长后,颗粒团聚逐渐严重,吸放氢性能下降.     

Combination of on-line preconcentration by di(2-ethylhexyl) phosphoric acid resin in the presence of complexing agent with microwave plasma-atomic emission spectrometry for the determination of rare earths

The adsorption of rare earths, lanthanum, cerium, neodymium, and yttrium by di(2-ethylhexyl) phosphoric acid (D2EHPA) resin in the presence of a complexing agent, EDTA, was investigated. Flow injection was selected as the injecting method. Various parameters, sample pH, sample loading time, sample flow rate, EDTA concentration, EDTA flow rate, eluent concentration, and eluent flow rate, were studied and optimized. Under the optimum conditions, the method allowed the determination of rare earths with detection limits of 1.09 μg/L (lanthanum), 3.31 μg/L (cerium), 2.05 μg/L (neodymium), and 1.25 μg/L (yttrium). High repeatabilities were obtained for all the four rare earths (RSD<5%). The proposed method was applied to the determination of the rare earths in water samples with a recovery range of 95.8%-103.3%.     

Synthesis and Characteristic Study on Complexes of Europium（Ⅲ） and Maleic Acid Doped with Non-Fluorescent Ions

Complex of europium （Ⅲ） with maleic acid, and binuclear complexes of europium（Ⅲ）with maleic acid doped with non-fluorescent ions gadolinium, lanthanum and yttrium, were synthesized. The compositions and structures of complexes were characterized with elemental analysis, single crystal X-ray diffraction, IR and DSC-TG. Fluorescent properties were studied with fluorescence spectrum. The results indicated that the strongest fluorescent complexes were obtained when the ratio of europium and non-fluorescent ion was 8：2. The order of Eu^3＋ fluorescence strengthened by three doped rare earths was Gd^3＋ 〉La^3＋ 〉Y^3＋     

Effect of Rare Earths on Corrosion Resisting Properties of Carbon-Manganese Clean Steels

Rareearthelementshavesignificantactionsinsteels ,includingwipingoffimpurityelements ,trans modifyinginclusions ,andimprovingmicrostructureetal,soaddingappropriaterareearthsintosteelscanef fectivelyimprovetheircorrosionresistingproper ties[1,2 ] .Todaypuri…     

Combination of on-line preconcentration by di(2-ethylhexyl) phosphoric acid resin in the presence of complexing agent with microwave plasma-atomic emission spectrometry for the determination of rare earths

The adsorption of rare earths,lanthanum,cerium,neodymium,and yttri um by di(2-ethylhexyl) phosphoric acid(D2EHPA) resin in the presence of a compl exing agent,EDTA,was investigated. Flow injection was selected as the injectin g method. Various parameters,sample pH,sample loading time,sample flow rate,EDTA concentration,EDTA flow rate,eluent concentration,and eluent flow rate,were studied and optimized. Under the optimum conditions,the method allowed the determination of rare earths with detection limits of 1.09 μg/L(lanthanum),3 .31 μg/L(cerium),2.05 μg/L(neodymium),and 1.25 μg/L(yttrium) . High repea tabilities were obtained for all the four rare earths(RSD<5%) . The proposed met hod was applied to the determination of the rare earths in water samples with a recovery range of 95.8%-103.3%.     

Structural Analysis and Electrical Property of Tungsten Bronze Prepared by Rare Earth Gaseous Permeation

The cubic sodium tungsten bronzes, NaxWO3 (x =0. 854 and 0. 814)were prepared by rare earths gaseous permeation method. Structural analysis was carried out by Rietveld method from powder X-ray diffraction data.The X-ray diffraction profile calculated with cubic P32 models are in good agreement with the observed X-ray diffraction patterns. There is only a little difference in W-O bond and Na-O bond between Na0.854 WO3 and Na0.814 WO3. Conductivity measurements indicate that NaxWO3 show anomalous semiconducting behavior and percolation model was used to interpret it.     

不同喂入位置条件下稀土在连铸板坯中分布及其对性能影响

通过化学分析、金相观察及冲击试验,分析了结晶器喂稀土及中间包喂稀土的连铸坯中夹杂物形态、分布,并测试了横断面上的冲击韧性.研究表明与结晶器喂稀土相比,中间包喂稀土的连铸坯中,稀土及夹杂物分布更均匀,夹杂物球化效果更好、尺寸更小、总数更少;冲击韧性明显高于未喂稀土,尤其是克服了连铸坯内弧侧四分之一范围冲击韧性的大幅降低的缺陷.因此,中间包喂稀土比结晶器喂稀土具有更大的优越性.     

Rare earths (Ce,Y, Pr) modified Pd/La_2O_3-ZrO_2-Al_2O_3 catalysts used in lean-burn natural gas fueled vehicles

14%REO_x-2.5%La_2 O_3-33.5%ZrO_2-50%Al_2 O_3(RE = Ce, Y, Pr) composites were prepared by a coprecipitation method. The Pd catalysts were obtained by an aqueous solution of Pd(NO_3)_2 loaded on the rare earths modified composites with an initial wet impregnated method. The experiment results show that catalytic activity of the rare earths modified Pd/La_2 O_3-ZrO_2-Al_2 O_3 catalysts is better than bare sample for methane oxidation. The structural characterization results reveal that the rare earths modified Pd catalysts increase amounts of surface active oxygen species by X-ray photoelectron spectroscopy(XPS) analysis and improve the dispersion of active component from H2-temperature programmed reduction(H2-TPR) measurement compared with bare sample. Especially,Pd/14%Y_2 O_3-2.5%La_2 O_3-33.5%ZrO_2-50%Al_2 O_3 sample exhibits highly active stability, it is related to the Pd particles highly dispersion,which was observed by transmission electron microscope(TEM) images.     

Preparation of mixed rare earths modified chitosan for fluoride adsorption

This paper described the fluoride removal from water using a new adsorbent namely mixed rare earths modified chitosan (CR). Mixed rare earths mainly contained La followed by Ce which was analyzed by in...     

中间包喂稀土消除连铸坯内弧侧卷渣缺陷原因研究

通过硫印试验、金相观察及冲击试验,比较了未喂稀土、结晶器喂稀土及中间包加稀土连铸坯内弧侧四分之一处夹杂物形态及分布及连铸坯横断面上的冲击韧性,发现结晶器喂稀土的连铸坯内弧侧卷渣缺陷形态及分布与未喂稀土的相近,冲击韧性变化也相同,而中间包加稀土基本消除了内弧侧四分之一处的卷渣缺陷,冲击韧性明显提高;并分析了中间包加稀土消除内弧侧卷渣原因.     

氮,氮,氮′,氮′-四辛基-3-氧戊二酰胺色谱柱分离-电感耦合等离子体质谱法测定混合稀土氧化物中重稀土

电感耦合等离子体质谱法(ICP-MS)测定稀土元素时,轻稀土元素Ce、Nd、Sm的氧化物等复合离子严重干扰重稀土元素Tb、Dy、Ho、Er的测定,因此对混合稀土中重稀土元素进行测定前一般需要先对其分离富集。实验在样品溶解后,将N,N,N′,N′-四辛基-3-氧戊二酰胺(TODGA)用硅藻土吸附后装柱,以0.1 mol/L HNO₃为样品溶液介质上柱,通过控制洗脱液的种类、酸度以及洗脱液流速,实现了轻稀土元素La、Ce、Pr、Nd与重稀土元素Tb、Dy、Ho、Er、Tm、Yb、Lu的分离和富集,建立了ICP-MS测定混合稀土氧化物中重稀土元素的方法。实验表明:控制洗脱流速为2.0 mL/min,用pH 2.0的HNO₃淋洗至淋洗体积约为500 mL,继续收集洗脱液,并用ICP-MS检测其中Nd₂O₃含量,直至洗脱液中Nd₂O₃的质量浓度小于200 ng/mL,可将轻稀土元素La、Ce、Pr、Nd及少量Y、Sm、Gd洗脱;再改用350 mL 1 mol/L HCl洗脱重稀土元素,可实现重稀土元素与La、Ce、Pr、Nd及部分Y、Sm、Gd的分离;通过选择¹⁵⁹Tb、¹⁶³Dy、¹⁶⁵Ho、¹⁶⁷Er、¹⁶⁹Tm、¹⁷²Yb、¹⁷⁵Lu为测定同位素可消除质谱干扰。将实验方法应用于混合稀土氧化物中重稀土元素的测定,加标回收率在93%～110%之间,相对标准偏差(RSD,n=8)在1.1%～10%之间。     

Improving Wear Resistance of the Ni-base Thermal Spray-Welding Coating Using Rare Earths

ＩｍｐｒｏｖｉｎｇＷｅａｒＲｅｓｉｓｔａｎｃｅｏｆｔｈｅＮｉｂａｓｅＴｈｅｒｍａｌＳｐｒａｙＷｅｌｄｉｎｇＣｏａｔｉｎｇＵｓｉｎｇＲａｒｅＥａｒｔｈｓＺｈａｉＧｕａｎｇｊｉｅ（翟光杰）（ＩｎｓｔｉｔｕｔｅｏｆＰｈｙｓｉｃｓ，ＡｃａｄｅｍｉｃａＳｉ...     

Study on Physical and Chemical Behaviors of Rare Earths in Preparing Ceramic Tube Supported Palladium Film by Electroless Plating

The rare earths of ytterbium, lanthanum, praseodymium, neodymium and their binary mixtures were respectively added into the traditional electroless plating solution to prepare thin palladium film on the inner surface of porous ceramic tube. The experimental results shows that the addition of rare earths increases palladium deposition rates and the binary mixtures are superior to the single rare earths and the mixture of ytterbium-lanthanum is the most efficient. Adding the mixture of ytterbium-lanthanum can also reduce the plating temperature by 10～20 ℃, shrink the metal crystal size and improve the film densification compared to those by traditional electroless plating. A thin palladium film with 5 μm was prepared and the film made a highly pure hydrogen with a molar fraction of more than 99.97% from a H2-N2 gas mixture. More attentions were paid to analyze the physical and chemical behaviors of the rare earths in palladium film preparation.