Corrosion resistance of plasma sprayed NiCrAl (ZrO_2 Y_2O_3) thermal barrier coating on 18-8 steel surface

1INTRODUCTION Austeniticstainlesssteelisdevelopedtocom pensateforpoorcorrosionresistanceofmartensite stainlesssteelandoverlargebrittlenessofferrite stainlesssteel.Basicconstituentsofitstypicalal loyare18%Crand8%Ni(massfraction),which isusuallycalledas188s…     

Properties of plasma sprayed NiCrAlY+(ZrO2+Y2O3) coating on refractory steel surface

NiCrAlY+(ZrO₂+Y₂O₃) thermal barrier coating was prepared on the surface of refractory steel 1Cr18Ni9Ti with plasma spraying technique. The phases and microstructure of the thermal barrier coating were determined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the bonding between thermal barrier coating and substrate is sound. The surface hardness of 1Cr18Ni9Ti reaches up to 1 000 HV, but that of substrate is only 300 HV. The patterns sprayed with CoNiCrAlY+(ZrO₂+Y₂O₃) ceramic coating have a good heat insulation effect at 800 °C for heat insulation temperature difference reaches 54 °C, which increases the operating temperature and service life of refractory steel. Foundation item: Project (5040202140) supported by Scientific Research Common Program of Beijing Municipal Commission of Education     

High temperature cyclic oxidation behavior of Y2O3-ZrO2 thermal barrier coatings irradiated by high-intensity pulsed ion beam

The high-temperature oxidation resistance behavior of 7% (mass fraction) Y₂O₃-ZrO₂ thermal barrier coatings (TBCs) irradiated by high-intensity pulsed ion beam (HIPIB) was investigated under the cyclic oxidation condition of 1 050 °C and 1 h. The columnar grains in the TBCs disappear after the HIPIB irradiation at ion current densities of 100–200 A/cm² and the irradiated surface becomes smooth and densified after remelting and ablation due to the HIPIB irradiation. The thermally grown oxide (TGO) layer thickness of the irradiated TBCs is smaller than that of the original TBCs. After 15 cycles, the mass gains of the original TBCs and those irradiated by ion current densities of 100 and 200 A/cm² due to the oxidation are found to be 0.8–0.9, 0.6–0.7, and 0.3–0.4 mg/cm², respectively. The inward diffusion of oxygen through the irradiated TBCs is significantly impeded by the densified top layer formed due to irradiation, which is the main reason for the improved overall oxidation resistance of the irradiated TBCs. Foundation item: Projects supported by The 2nd Stage of Brain Korea and Korea Research Foundation     

Investigation on plasma-sprayed ZrO2 thermal barrier coating on nickel alloy substrate

The thermal barrier coatings with NiCrAlY alloy bonding layer, NiCrAlY-Y₂O₃ stabilized ZrO₂ transition layer and Y₂O₃ stabilized ZrO₂ ceramic layer are prepared on nickel alloy substrates using the plasma spray technique. The relationship among the composition, structure and property of the coatings are investigated by means of optical microscope, scanning electronic microscope and the experiments of thermal shock resistance cycling and high temperature oxidation resistance. The results show that the structure design of introducing a transition layer between Ni alloy substrate and ZrO₂ ceramic coating guarantees the high quality and properties of the coatings; ZrO₂ coatings doped with a little SiO₂ possesses better thermal shock resistance and more excellent hot corrosion resistance as compared with ZrO₂ coating materials without SiO₂; the improvement in performance of ZrO₂ coating doped with SiO₂ is due to forming more dense coating structure by self- closing effects of the flaws and pores in the ZrO₂ coatings. Biography of the first author: LU An-xian, Ph.D, professor, born in Jan. 1960, majoring in inorganic non-metal materials.     

Properties of plasma sprayed NiCrAlY (ZrO_2 Y_2O_3) coating on refractory steel surface

1INTRODUCTION1Cr18Ni9Ti,i.e.188austeniticstainless steel,isakindofausteniticrefractorysteelwidely appliedinmanyfields,containingahighcontentofCrthatcanimproveheatandoxidationresistances,andalsoNicapableofformingastableaustenitic structure.However,suchstee…     

NiCoCrAlY/Al_2O_3-13%TiO_2复合涂层的耐锌铝腐蚀性

为了解决热镀锌铝工艺中沉没辊受到熔融锌铝液腐蚀的问题,采用超音速火焰喷涂技术在316L基体上制备了NiCoCrAlY粘结层,并利用等离子喷涂技术制备了NiCoCrAlY/Al_2O_3-13%TiO_2复合涂层.结果表明,复合涂层界面处的热膨胀系数突变减缓,使得界面处的应力集中减少,从而对裂纹扩展起到延缓和抑制作用,因而复合涂层的抗裂性能增强.复合涂层在锌铝液中的使用寿命可以达到9 d,高于传统Al_2O_3-13%TiO_2涂层.复合涂层的结合强度也高于传统Al_2O_3-13%TiO_2涂层,但复合涂层的最终失效形式依然是由两种材料的热胀系数不匹配所导致的涂层开裂.     

Luminescent properties of BaO-La2O3-B2O3 glasses with dopant

The luminescent properties of glasses synthesized in air atmosphere by conventional high temperature process were stud{ed. The emissions spectra of Eu^2 and Eu^3 were observed in BaO-La2O3-B2O3-Eu2O3 glasses.The results show that the broad emission peaks at 430 nm correspond to 5d→4f emission transition of Eu^2 , the sharp emission peaks at 592, 616, 650 and 250 nm correspond to 5^D0→1Fj(j=1--4) emission transition of Eu^3 ,respectively, which indicates that the BaO-La2O3a-B2O3-Eu2O3 glass can convert ultraviolet and green omponents of sunlight into blue and red light so as to increase the intensity of blue and red light, respectively. The luminescent in--tensity of Eu^2 increases with increasing the molar ratio of Tb^3 in BaO-La2O3-B2O3-Eu2O3a-Tb4O3 glasses, whereas the luminescent intensity of Eua^3 decreases. So the luminescent intensity of Eu(Ⅲ,Ⅱ) is influenced by Tb^3 .These phenomena can be explained by electron transfer mechanism; Eu^3 (4f6) Tb^3 (4f^8)→Eu^2 (4f′) Tb^4 (4f′). Taking advantage of the luminescent properties of BaO-La2O3-B2O3-Eu2O3 glasses, light-conversion glass for agriculture can be produced.     

碳钢电极在Al_2O_3纳米流体中的腐蚀行为研究

采用电化学阻抗谱和极化曲线研究了碳钢电极在以模拟冷却水为基液的Al_2O_3纳米流体中的腐蚀行为.实验结果表明,Al_2O_3纳米颗粒对碳钢的腐蚀有一定的抑制作用;Al_2O_3纳米流体中碳钢电极的耐蚀性能随着温度的升高而降低,添加分散剂十二烷基苯磺酸钠(SDBS)对碳钢也有一定的缓蚀作用,当SDBS的用量超过一定值时,对碳钢的缓蚀性能开始下降.     

基于双金属MOFs 制备Co3O4/In2O3 复合物及其气敏性能的研究

以硝酸铟(In(NO₃)₃·xH₂O)、对苯二甲酸(H₂BDC)、六水合硝酸钴(Co(NO₃)· 6H₂O) 为原料, 首先采用一锅油浴法合成了含有Co²⁺ 的铟基金属有机框架材料(MOFs) Co²⁺/CPP-3(In) 材料, 然后在450 ℃ 下焙烧制备Co₃O₄/In₂O₃ 复合物气敏材料, 将Co₃O₄/In₂O₃ 复合物的粉体制作成传感器, 并对其气敏性能进行研究。利用扫描电子显微镜和X 射线衍射仪(XRD) 对双金属MOFs Co²⁺/CPP-3(In) 材料和Co₃O₄/In₂O₃ 复合物进行表征, 采用静态配气法测试其气敏性能。结果表明, Co₃O₄/In₂O₃(n_Co : n_In = 0.4 : 1) 样品的形貌保留了其MOFs 前驱体的棒状结构, 棱柱形框架更为突出, 表面呈凹陷状, 棒体中间粗两边细, 六角截面和棒体均布满了孔洞。结合EDX 和XRD 表征结果, Co²⁺/CPP-3(In) MOFs 前驱体完全转化成Co₃O₄/In₂O₃ 复合物; Co₃O₄/In₂O₃(n_Co : n_In = 0.4 : 1) 复合物在 70 ℃ 下对5×10^-6 H₂S 的气敏性能最优, 响应值达到153, 是同条件下纯备In₂O₃对H₂S 响应值的5 倍, 并且有较好的重复性、选择性和稳定性。     

Influence of oxides on high velocity arc sprayed Fe-Al／Cr3C2 composite coatings

Fe-Al/Cr3C2 coatings were sprayed on low steel by high velocity arc spraying(HVAS) technology. The influences of oxides on erosion, corrosion and wear behavior for high velocity arc sprayed Fe-Al/Cr3C2 coatings were studied. The results show that HVAS-sprayed Fe-Al/Cr3C2 coatings have good erosion, heat corrosion and wear resistance. The erosion resistance improves with the increase of the temperature. On one hand, the ferrous oxides are incompact, so they peel off the surface of the coatings easily during the high temperature erosion. On the other hand, compact Al2O3 films on the surface can protect the coatings.     

纳米Al2O3改性环氧胶黏剂和钢铁附着机理的研究

通过拉拔法测定纳米Al₂O₃改性环氧胶黏剂和钢铁之间的附着强度,并结合环氧胶的表面能参数测定以及X射线光电子能谱(XPS)分析,对纳米Al₂O₃提高环氧胶和钢铁附着力的机理进行研究.表面能测定结果表明,添加纳米Al₂O₃使环氧胶的极性增加;XPS能谱分析结果表明,当纳米Al₂O₃质量分数达到2%时,环氧胶中形成新的羧基极性基团;进一步研究发现,当纳米Al₂O₃质量分数为1%时未形成新的羧基基团,当纳米Al₂O₃质量分数为8%时单位接触面积上新的羧基基团的数目较2%时少,这与附着强度的变化规律是一致的.因此,纳米Al₂O₃改性的环氧胶黏剂与钢铁的附着强度的增强是由于Al₂O₃与环氧胶的相互作用形成了新的羧基极性基团．     

Modification of nano-TiO2 by Al2O3 in-situ coating

A novel technology of in-situ coating Al₂O₃ on the surface of H₄TiO₄ was developed to prevent the aggregation of nano-TiO₂ powders and improve the dispersibility and thermal stability in the way of forming a uniform coating layer. The heterogeneous nucleation was conducted to prepare the precursor of nano-TiO₂ and then Al₂O₃ was coated on the surface of precursor. The effects of Al₂O₃ in-situ coating on the properties of nano-TiO₂ were investigated. The results show that H₄TiO₄ can be dispersed well under alkaline condition (pH 8.5) and the heterogeneous nucleation can be controlled easily. The optimized uniform coating layer is obtained by adding 5% (mass fraction) and 10% of Al₂O₃ and the aggregation of nano-TiO₂ powders is effectively inhibited and the dispersibility is obviously improved. The crystal sizes of TiO₂ powders are 12.3, 11.4 and 8.7 nm after coating 0,5% and 10% of Al₂O₃ respectively. Al₂O₃ on the surface of particulates in amorphous phase could increase the thermal stability of nano-particles after calcined at 550 °C. Foundation item: Project(04GK2007) supported by Hunan Industrial Key Project of Science and Technology     

激光熔覆Ni+Cr_2O_3复合涂层的耐蚀性

研究了激光搭接熔覆Ni+Cr2 O3复合涂层在 0 .5mol/LH2 SO4 +0 .5mol/LNaCl水溶液中的电化学行为 .试验表明Cr2 O3粒子在激光熔池中发生了完全溶解 ,涂层具有胞状枝晶组织特征 .激光熔覆Ni+Cr2 O3复合涂层比单一熔覆Ni合金涂层和 2Cr13马氏体不锈钢基材具有更低的维钝电流密度和更宽的钝化区范围 ,明显改善了在该腐蚀介质中的抗点蚀能力 .     

Al_2O_3包覆对富锂锰基正极材料Li_(1.2)Mn_(0.54)Co_(0.13)Ni_(0.13)O_2的电化学性能影响

采用水热法合成富锂三元正极材料,探究了最佳包覆比例下Al_2O_3包覆对材料的电化学性能影响.采用扫描电镜(SEM)和X射线衍射仪(XRD)表征了富锂三元正极材料的表面形貌和结构,通过循环伏安(CV)、交流阻抗(EIS)技术分析了材料电化学性的影响因素.结果表明,通过异丙醇铝水解制得了氧化铝包覆层,提高了材料的比容量,稳定了材料的结构.     

Modification of LiCo1/3Ni1/3Mn1/3O2 cathode material by CeO2-coating

LiCo_1/3Ni_1/3Mn_1/3O₂ was coated by a layer of 1.0 wt% CeO₂ via sol-gel method. The bared and coated LiMn_1/3Co_1/3Ni_1/3O₂ was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammogram (CV) and galvanotactic charge-discharge test. The results show that the coating layer has no effect on the crystal structure, only coating on the surface; the 1.0 wt% CeO₂-coated LiCo_1/3Ni_1/3Mn_1/3O₂ exhibits better discharge capacity and cycling performance than the bared LiCo_1/3Ni_1/3Mn_1/3O₂. The discharge capacity of 1.0 wt% CeO₂-coated cathode is 182.5 mAh·g⁻¹ at a current density of 20 mA·g⁻¹, in contrast to 165.8 mAh·g⁻¹of the bared sample. The discharge capacity retention of 1.0 wt% CeO₂-coated sample after 12 cycles reaches 93.2%, in comparison with 86.6% of the bared sample. CV results show that the CeO₂ coating could suppress phase transitions and prevent the surface of cathode material from direct contact with the electrolyte, thus enhance the electrochemical performance of the coated material.     

Theoretic Diffraction Research on the Order-Disorder Effect of Transition Metal in Li(Ni1/3Co1/3Mn1/3)O2

Li(Ni_1/3Co_1/3Mn_1/3)O₂的(3b)位有序-无序效应研究

曹春晖^1,2, 张建¹, 杨传铮¹, 夏保佳¹

（1.上海微系统与信息技术研究所,上海 200050;

2.中国科学院大学, 北京100049）

创新点说明：

提出了有序度的概念,通过理论模拟了过渡金属在3b位不同有序度下的衍射情况。

研究目的：

借助理论衍射研究镍钴锰在三元材料中的占位情况,为实际得到的衍射数据分析起指导作用。

研究方法和结果：

借助Powercell程序模拟不同结构下的衍射情况。结果表明：对于Li(Ni1/3Co1/3Mn1/3)O2,基体衍射线的强度不随有序度而变化,有序度增加时,超点阵衍射线强度增加,但是即使对于有序度最大时,超点阵线的相对强度只有0.225%和0.043%。

结论：

3b位的有序无序很难通过常规的衍射实验观测到,必须提高X射线源的强度才可能观测到。

关键词：Li(Ni1/3Co1/3Mn1/3)O2, 有序-无序,超结构,衍射

     

Solvothermal preparation and characteristics of Sn-doped In2O3

Sn-doped In2O3 （ITO） nanopowders were prepared in ethanol solvent by solvothermal process. The effects of the solvothermal temperature, coprecipitation pH value and SnO2 content on the products phase and microwave absorption were investigated by X-ray diffractometry and microwave reflectance. ITO nanopowders with cubic structure can be respectively prepared at 250 and 270 ℃ for 6 h. The prepared product is InOOH or the mixture of InOOH and In3Sn4O12 when the solvothermal temperature is below 250℃. With rising solvothermal temperature and prolonging time, the absorption of the ITO powders gradually decreases. The products are ITO nanopowders by coprecipitating at pH=9 or 11, but ITO powders with Sn3O4 at pH=6. The absorption of powders prepared at pH=6 is better than that at any other pH value. The products are all ITO nanopowders and crystal size reduces with increasing SnO2 content. The microwave absorption of ITO nanopowders with SnO2 content of 8% （mass fraction） is the best among samples with different SnO2 contents.     

Pressureless sintered 3Y-TZP/20%Al2O3 composite ceramic

Nanometer 3Y-TZP/20%Al₂O₃ (mass fraction) composite powders prepared by the chemical coprecipitation method were pressureless sintered at 1550 °C for 2 h. Effects of calcining temperatures at 800 °C, 1 000 °C, and 1 200 °C on phase structure, relative density, and Vicker’s hardness of the sintered bodies were studied. The results show that 1 000 °C was the optimal calcining temperature, and the powder calcined was composed of tetragonal zirconia with the Scherrer crystalline size of 6.3nm. The relative density was up to 98.5% under pressureless sintering, and the sintered body was t-ZrO₂ (without m-ZrO₂)+α-Al₂O₃ with the average size of 0.4 μm. Foundation item: State Key Laboratory for Powder Metallurgy(No.9706-36) Biography of the first author: YIN Bang-yao, born in 1966, majoring in advanced ceramic materials.     

Molar heat capacities of La2Mo2O9 and La1.9Sr0.1MO209-δ

The molar heat capacities of La2Mo209 and La1.9Sr0.1MO209-δ were obtained using the differential scanning calorimetry （DSC） technique in a temperature range from 298 to 1473 K. The DSC curve of La2Mo209 showed an endothermal peak around 834 K corresponding to a first-order monoclinic-cubic phase transition, and the enthalpy change accompanying this phase transition is 5.99 kJ/mol. No evident endothermal peak existed in the DSC curve of La1.9Sr0.1MO209-δ, but a broad thermal anomaly existed in its heat capacity curve at around 832 K. In addition, the heat capacity values of La2Mo209 and La1.9Sr0.1MO209-δ began to decrease at 1196 and 1330 K, respectively. The non-transitional heat capacity values of La2Mo209 and La1.9Sr0.1MO209-δ were formulated using multiple regression analysis in two temperature ranges.     

Antibiotic properties of Al2O3 doping silver

The preparation technique and properties of Ag-type inorganic antibiotic material carried by Al₂O₃ were studied. The results show that the material has good antibiotic and safety properties, the acute toxicity taken by stomata is LD ₅₀>8 000 mg/kg (little and big white rats), and the normal quantity in subacute toxicity test is 80 mg/(kg · d). The better mass fraction of doping Ag₂O in antibiotic material carried by Al₂O₃ is 4%–8%, and the optimal sintering temperature is from 1 000 °C to 1 100 °C. Foundation item: Project (2002AA327090) supported by National High Technology Research and Development Program of China