Effect of two-step solid solution on microstructure andδphase precipitation of Inconel 718 alloy

Inconel 718 is the most popular nickel-based superalloy and is extensively used in aerospace,automotive,and energy indus-tries owing to its extraordinary thermomechanical properties.The effects of different two-step solid solution treatments on microstructure andδphase precipitation of Inconel 718 alloy were studied,and the transformation mechanism fromγ″metastable phase toδphase was clarified.The precipitates were statistically analyzed by X-ray diffractometry.The results show that theδphase content firstly increased,and then decreased with the temperature of the second-step solid solution.The changes in microstructure andδphase were studied by scanning electron microscopy and transmission electron microscopy.An intragranularδphase formed in Inconel 718 alloy at the second-[100]_(δ)[011]γ step solid solution temperature of 925℃,and its orientation relationship withγmatrix was determined as//and(010)_(δ)//(111)γ.Furthermore,the Vickers hardness of different heat treatment samples was measured,and the sample treated by second-step solid solution at 1010℃ reached the maximum hardness of HV 446.84.

Acting mechanism of F,K,and Na in the solid phase sintering reaction of the Baiyunebo iron ore

The effect of F,K,and Na on the solid phase reaction of the Baiyunebo iron ore was investigated by differential thermal analysis （DTA） and X-ray diffraction（XRD）.It has been identified that alkaline elements K and Na in the Baiyunebo ore instigate the formation of low melting point compounds Na2SiO3 and Na2O·Fe2O3 and the generation of molten state in the solid phase sintering.Element F in the Baiyunebo ore facilitates the formation of cuspidine compound 3CaO·2SiO2·CaF2 in the solid phase reaction.The cuspidine compound is kept in solid as one of the final products through the entire sintering process due to its high melting point.In the sintering process,CaF2and SiO2 react with CaO first and form 3CaO·2SiO2·CaF2 and 3CaO·2SiO2,so the formation of ferrites,Na2O·Fe2O3,and 2CaO·Fe2O3 is inhibited.

Fabrication of solid-phase-sintered Si C-based composites with short carbon fibers

Solid-phase-sintered Si C-based composites with short carbon fibers（Csf/SSi C） in concentrations ranging from 0 to 10wt% were prepared by pressureless sintering at 2100°C. The phase composition, microstructure, density, and flexural strength of the composites with different Csf contents were investigated. SEM micrographs showed that the Csf distributed in the SSi C matrix homogeneously with some gaps at the fiber/matrix interfaces. The densities of the composites decreased with increasing Csf content. However, the bending strength first increased and then decreased with increasing Csf content, reaching a maximum value of 390 MPa at a Csf content of 5wt%, which was 60 MPa higher than that of SSi C because of the pull-out strengthening mechanism. Notably, Csf was graphitized and damaged during the sintering process because of the high temperature and reaction with boron derived from the sintering additive B4C; this graphitization degraded the fiber strengthening effect.

Pressureless reactive sintering mechanism of nanocrystalline Bi_2O_3-Y_2O_3 solid electrolyte

The nanocrystalline Bi2O3-Y2O3 solid electrolyte material was synthesized by pressureless reactive sintering process with Bi2O3 and Y2O3 nano mixed powder as raw materials, which was prepared by a chemical coprecipitation process. The study on the behavior of nano δ-Bi2O3 formation and its grain growth showed that the solid solution reaction of Y2O3 and δ-Bi2O3 to form δ-Bi2O3 occurs mainly in the initial stage of sintering process, and nano δ-Bi2O3 crystal grains grow approximately following the rule of paracurve （（D-D0）^2=K.t） during sintering process. After sintered at 600℃ for 2 h, the samples could reach above 96% in relative density and have dense microstructure with few remaining pores, the δ-Bi2O3 grains are less than 100 nm in size.

Synthesis and Solid Phase Extraction Performance Study of NNAL-specific Molecularly Imprinted Polymers Using Dummy Templates

Dummy molecularly imprinted polymers （DMIPs） for 4-（methylnitrosamino）-1-（3-pyridyl）-1-butanol （NNAL） were produced using three structural analogues as dummy template molecules. The chosen analogues were 4-（acetymethylamino）-1-（3-pyridyl）-butanol, 4- （methylamino）-1-（3-pyridyl）-1-butanol, and 1-（3-pyridyl）-1,4,-butanediol. The molecular recognition characteristics of the produced polymers were evaluated by X-ray photoelec- tron spectroscopy （XPS） and Fourier transform infrared spectroscopy （FT-IR）. Interactions between NNAL and methacrylic acid should be cooperative hydrogen bonds while the ni- trogen atom of the pyridine ring and the oxygen atom of the nitroso group in NNAL are two of the hydrogen-bond acceptors. It was further demonstrated that DMIP synthesized by 4-（acetymethylamino）-1-（3-pyridyl）-butanol had the best binding performance by XPS and FT-IR. Then dummy molecularly imprinted solid phase extraction （DMISPE） was developed for the determination of the analyte using the hit polymer as the sorbing material. Under optimal conditions, the recovery of NNAL dissolved in standard solution reached 93%. And the investigated polymer exhibited much higher binding of NNAL when nicotine was acted as the competitive molecule. Also the proposed method was applied to the measurement of NNAL spiked in blank urine samples with recoveries ranging from 87.2% to 101.2%.

K掺杂的SrSiO_(3-δ)基电解质材料的制备与性能研究

采用固相法制备了固体氧化物燃料电池(SOFC)电解质材料Sr_(1-x)K_(x)SiO_(3-δ)(x=0.00、0.05、0.10、0.15、0.20、0.25、0.30、0.35)。通过红外光谱、X射线衍射、扫描电镜、交流阻抗等对试样进行表征分析。结果表明:用固相法经950℃煅烧所得粉体呈立方钙钛矿结构。Sr_(1-x)K_(x)SiO_(3-δ)的烧结活性较好,在1200℃烧结的电解质陶瓷相对密度均大于98%,平均晶粒尺寸为7~15μm;中温条件下该系列电解质材料的离子电导率较高、电导活化能较低。其中800℃时Sr_(0.90)K_(0.10)SiO_(2).95的离子电导率最高(8.66×10^(-2)S/cm),电导活化能最低(1.27 eV)。

Al-Mg共掺杂钴酸锂的合成及其电化学性能研究

钴酸锂(LCO)作为锂电池正极材料,在电子产品领域有非常广泛的应用,但由于高电压下会导致其晶相的不可逆相变从而导致循环稳定性降低,因此如何提高钴酸锂在高电压下的电化学稳定性一直是研究热点。为了改善钴酸锂的电化学稳定性,采用固相球磨-烧结法合成了Al-Mg共掺杂的LCO材料。采用X射线衍射(XRD)和扫描电镜(SEM)及电化学性能测试表征晶体结构、形貌和测量其循环稳定性。结果表明:Mg、Al进入钴酸锂晶格内部后有效地提高了其电化学稳定性,当Al掺杂量为0.1%,Mg掺杂量为1%时,在0.5C的倍率,3~4.5V的电压下,首圈放电比容量可达136.7mAh/g,100圈后的容量保持率可达76.2%,同时也表现出了良好的倍率性能。

Single Phase Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB>Synthesis for Nanoparticles by Two Steps Sintering

Li4Ti5O12 has been noticed about a negative electrode of a high powered and safe lithium ion secondary battery. These properties require single phase, high crystallization, larger specific surface area and fine nanoparticles. This study carried out the noble synthesis of Li4Ti5O12 using a solid phase synthesis by two steps sintering. These results showed Li4Ti5O12 of 6.1 m2&middotg-1?and diameter of 110 nm with the single phase and high crystallization. Li2TiO3 will play an important role in this reaction, obtained by pre-sintering as a precursor.

Solid-phase Synthesis of-Haloaldehydes from Polymer-supported 4-(Phenylseleno)morpholine

Polystyrene-supported 4-(phenylseleno)morpholine was synthesized and could be used as an efficient ?selenenylating agent for saturated aldehydes. ?Haloaldehydes were prepared by reaction of polystyrene-supported ?selenoaldehydes with bromine or sulfuryl chloride in good yield and high purity.

Solid-Phase Stereoselective Synthesis of (E)-1, 2-Disubstituted Ethenes from Polymer-Sopported a-Selenoaldehydes

Reaction of polymer-supported a-selenoaldehydes with Grignard reagents afforded polymer-bound B-hydroxyalkyl selenides, which treated with thionyl chloride and triethylamine leading to (E)-1, 2-disubstituted ethenes in good yield.

Fe-44.4%Mo-4.9%B-2.5%Cr-2.9%Ni金属陶瓷烧结阶段晶粒生长机理

Mo_(2)FeB_(2)基金属陶瓷是以Mo、Fe、Cr、Ni、FeB、C为原料,采用反应硼化烧结法制备而成,具有高硬度、高强度和高韧性的特点,并且制造成本相对低廉。本文采用真空液相烧结的方法制备Fe-44.4%Mo-4.9%B-2.5%Cr-2.9%Ni金属陶瓷,研究固相、液相烧结阶段金属陶瓷硬质相形貌及生长过程与机理。结果表明:在600℃前,Fe与片状FeB生成Fe_(2)B相,进入固相烧结阶段;随温度升高至900℃,在升温过程中Mo在Fe_(2)B界面上与Fe_(2)B反应形核生成Mo_(2)FeB_(2),生长方式表现为螺旋生长,并且形成生长台阶;温度继续升高至1000℃,Mo_(2)FeB_(2)晶粒继续长大,突破临界半径,开始析出小Mo_(2)FeB_(2)晶粒;温度升高至1050℃,溶解析出一直进行,Mo_(2)FeB_(2)开始长大成截面为正六方形的晶粒。期间经历形核、螺旋生长、溶解析出、形成截面为正六方形晶粒四个阶段,最终由Mo和FeB、Fe_(2)B相形成正六方形的Mo_(2)FeB_(2)晶粒。在1050℃后会进入液相烧结阶段,Mo_(2)FeB_(2)硬质相柱状生长,其长轴、短轴晶粒生长激活能分别为317 kJ/mol和402kJ/mol,因此Mo_(2)FeB_(2)晶粒更易沿长轴生长,最终生长为长条状。

Solid-phase Synthesis of Unsaturated β-Dicarbonyl Compounds from Polymer-supported 4-(Phenylseleno)morpholine

The solid-phase synthesis of unsaturated ?dicarbonyl compounds has been reported.

Synthesis and Characterization of Magnetic MAX Phase(Cr2-xMnx)GaC

The solid solution of (Cr2-xMnx)GaC with magnetic properties was synthesized by pressureless sintering.The composition,morphology,and magnetic properties of products were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),transmission electron microscopy (TEM),and vibrating sample magnetometer (VSM).The experimental results indicate that the solid solubility of Mn is related to the value of x,which reaches the maximum at x=0.4 and the characteristic peaks shift effect is most obvious.After the solution treatments,the samples of (Cr2-xMnx)GaC still presents the layered structure of MAX phase,and the lattice parameter has decreased slightly.By characterizing the magnetic properties of (Cr2-xMnx)GaC,the successful doping of Mn atoms was confirmed,and the intensity of magnetism was positively correlated with the doping amounts of Mn.

Subsolidus Conceptual Design of CaO-AI_2O_3-TiO_2-SiO_2 System and Its Significance for Manufacturing Advanced Ceramics

The article deals the structure of the CaO -Al2O3 - TiO2 -SiO2 system as a basis for obtaining advanced ce- ramics with a complex of high-operational characteris- tics. As a result o[＇investigations the phase charctcteristics are represented trod the graph of the relationship of the elementaory tetrahedra has been plotted. The most techno- logical system area ,for the production of heat resistant advanced ceramics has been determined. The batches for producing heat and chemical resistant dense advanced ceramics made of natural, technical and technogenic raw materials have been developed.

Phase evolution mechanism study and fabrication of PbMo_(6)S_(8) superconducting materials with two-step sintering process

PbMo6S 8 superconducting materials are considered to have great potential for practical applications at low temperatures and high fields due to their high upper critical field,low anisotropy,and low preparation cost.In this work,PbMo_(6)S_(8) bulks were prepared through a solid‐state sintering process using PbS,Mo,and MoS_(2) as raw materials.The phase evolution mechanism during the sintering of PbMo_(6)S_(8) was studied in detail.It was found that during sintering at 750℃ for 24 h,both the S and Pb atoms diffuse into the Mo and MoS_(2) particles,leading to the formation of the PbMo_(6)S_(8) phase.After sintering at 950℃ for 72 h,a high superconducting phase content was obtained in the bulk;however,numerous pores remained.Therefore,in order to obtain a higher density for the bulk,a two‐step sintering process was developed.Based on this technique,PbMo_(6)S_(8) bulks with a higher bulk density and a higher superconducting phase content were obtained.This study provides an effective method for the fabrication of high‐quality precursor powders,which can be the foundation for the future fabrication of PbMo_(6)S_(8) superconducting long wires or tapes for practical applications.

姜花香气成分的SPME-GC-MS分析

姜花原产我国南部、西南部,印度、马来西亚也有分布,姜花为姜科姜花属多年生草本植物,其花香芬芳纯正,沁人心脾,很受人们喜爱.姜花清芬宜人,早已成为提取芳香油的工业原料,用以制备高级化妆品.……

CuO-TiO_2复合助剂低温烧结氧化铝陶瓷的机理(Ⅰ)

向氧化铝陶瓷中添加总量固定、但m(CuO)/m(TiO_2)不同的CuO-TiO_2复合助剂,研究其对氧化铝陶瓷烧结性能、微观结构以及物相组成的影响,揭示复合助剂的低温烧结机理.结果表明,CuO与TiO_2不易发生化合反应,分别以液相烧结和固相反应烧结来促进氧化铝陶瓷的致密化进程;TiO_2与Al_2O_3反应生成Al_2Ti_7O_(15)的固相烧结,比CuO的液相烧结更能有效地促进陶瓷的晶粒生长与致密化.在TiO_2固相烧结的基础上适当引入CuO液相,能够最大程度地降低氧化铝陶瓷的烧结温度;当在50 g Al_2O_3粉体中添加总量为0.025 mol的CuO-TiO_2复合助剂,并使m(TiO_2)/m(CuO+TiO_2)为0.80时,氧化铝陶瓷在1250℃烧结后其密度达到理论密度的98%以上.

颗粒级配对选区激光烧结打印结合常压固相烧结制备碳化硅陶瓷性能的影响

SiC陶瓷因其独特的热学、电学性能及优异的力学性能,被广泛应用于航空航天、核能、化工、半导体等国防与工业重大领域,但是传统的成型方法无法满足大尺寸复杂构件的制备需求。选区激光烧结(SLS)打印具有无需支撑、材料利用率高、加工效率高等优势,能高效成型复杂陶瓷结构零部件。本研究采用颗粒级配SiC的方法,系统研究了冷等静压(CIP)、前驱体浸渍热解(PIP)、CIP结合PIP后常压固相烧结等工艺对级配和中位径82μm未级配体系SiC陶瓷的影响。研究发现,级配粉末成型坯体的体积密度和抗弯强度比未级配坯体均提升了20%以上,级配体系CIP后常压固相烧结体的相对致密度达到了90%以上,实现了致密化烧结,而未级配体系烧结体的相对致密度仅为89%,这是由颗粒级配后坯体的堆积密度提升所致,且级配烧结体的抗弯强度(136.8 MPa)比未级配(99.4 MPa)提升了37%以上。采用多次重复PIP结合常压固相烧结的方法制备高致密的SiC陶瓷,发现SLS打印成型的坯体经四次PIP后致密度可达到CIP堆积致密的效果,但四次PIP后常压固相烧结体的体积密度仅为2.29 g/cm^(3),抗弯强度为59.6 MPa。

液相色谱-质谱联用测定乌头碱血药浓度及其药代动力学参数的方法学研究

乌头碱(aconitine)是存在于乌头属多种植物中的一种双酯二萜生物碱,具有镇[1]、抗炎[2]、抗癫痫[3]、抗肿瘤[4]、提高免疫功能[5]等多种生理活性,但因其具有强烈的心脏毒性和神经毒性,安全系数小,治疗剂量与中毒剂量接近(小鼠LD501.8mg/kg,op;人绝对致死量为2～5mg)[7],限制了对该化合物作为药用的进一步研究,目前仅将其作为致心率失常模型的工具药使用,尚未见其药代动力学的报道.在本文中首次应用液相色谱-质谱联用法对乌头碱在大鼠体内的药代动力学进行了研究.……

液相色谱-串联质谱同时测定禽肉组织中盐酸金刚烷胺、盐酸金刚乙胺、地塞米松、替米考星及喹乙醇代谢物的残留量

建立了同时测定禽肉组织中盐酸金刚烷胺、盐酸金刚乙胺、地塞米松、替米考星及喹乙醇代谢物残留量的液相色谱-串联质谱分析方法.样品用2 mol/L氢氧化钠溶液水解,盐酸调节pH值后,以乙腈作为提取溶剂,经C18固相萃取柱净化.各待测物分别经0.1％甲酸甲醇溶液和氨化甲醇（0.1％氨水）洗脱,Phe-nomenex Kinetex C1s（100 mm×4.6 mm,2.6 μm）色谱柱进行分离,采用0.1％甲酸（含5 mmol/L乙酸铵）-甲醇作流动相,梯度洗脱,串联质谱法对5种药物含量进行测定.结果表明,5种药物在2 ～ 100 μg/L范围内线性关系良好,相关系数为0.996 2 ～0.999 8.在加标浓度为5～50 μg/kg的禽肉组织中,这5种药物的加标回收率为73.7％ ～92.3％,相对标准偏差（n=5）为3.9％ ～ 16.6％,检出限为0.2～ 3.0 μg,/kg,定量下限为0.7～ 10 μg/kg.方法快速、简便、经济实用,符合法规要求,可满足日常检测的需要.