Highly textured and strongly anisotropic TiB2 ceramics prepared using magnetic field alignment (9T)

Highly textured TiB₂ ceramics were prepared by slip casting an aqueous suspension in a magnetic field of 9 T, followed by sintering using Field Assisted Sintering Technology (FAST). Particle size refinement by ball milling improved both the degree of texturing and densification of the material (RD > 98 %). The sintered material exhibited a Lotgering orientation factor of 0.90, with the c-axis of TiB₂ oriented parallel to the magnetic field and FAST pressing direction. The texturing effect induced by the uniaxial pressing was negligible. The textured TiB₂ material exhibited a significant anisotropy in mechanical properties; the values of hardness and indentation elastic modulus measured along directions transverse to the c-axis of TiB₂ were 37 % and 13 % higher than the ones measured along the c-axis direction. Moreover, the specific wear rate of a surface of textured TiB₂ parallel to the field was one order of magnitude lower than a surface perpendicular to the field.     

Corrosion behaviour of AA2024 aluminium alloy in different tempers in NaCl solution and with the CeCl3 corrosion inhibitor

The paper analyses the corrosion behaviour of naturally and artificially aged AA2024 alloy in NaCl solution and in the presence of an environment-friendly corrosion inhibitor, CeCl₃. On the basis of the values of polarisation resistance and corrosion current density, the corrosion resistance of the protective inhibitor film is established as well as the general corrosion resistance of this aluminium alloy. Resistance to pit formation is determined based on the difference in pitting and corrosion potentials while resistance to pit growth is determined based on the amount of charge consumed during pit growth. A scanning electron microscope is used to examine the morphology of the pits formed during the pitting corrosion testing, as well as to determine the cerium content on intermetallic particles and the matrix AA2024 alloy. The corrosion behaviour of AA2024 alloy is investigated after different test periods in NaCl solution and in the same solution with the CeCl₃ inhibitor. The corrosion resistance of both tempers of AA2024 alloy is more than one order of magnitude higher in the presence of CeCl₃. An explanation of the observed differences in the corrosion behaviour of the naturally and artificially aged AA2024 alloy is proposed. Different corrosion behaviour of the alloy after different test periods is also explained.     

雕刻技术的研制和应用

在对铝合金铸件进行X射线实时探伤时，由于采集回来的许多图像的目标物体的轮廓比较模糊，这样在评片时容易造成对铸件的误判和漏判。针对这种现象并结合这类图像噪声源多的特点，在研究常用卷积算法的基础上，采用特殊卷积（特殊的卷积核）操作，同时根据雕刻的艺术底色为灰色，最后给卷积结果加上灰度值128，实验结果表明图像中目标物体的轮廓变得更清楚，同时处理后的图像具有比较好的三维效果，这给工作人员在看图时带来了方便。     

Microstructures and Phase Transition Points of As-Cast Mg-Zn-Y System Alloys

As-east mierostruetures and their distribution of Mg-Zn-Y ternary alloy with high magnesium, low zinc and yttrium were examined using Nikon Epiphot optical microscopy （OM）, RigakuD/max-3C X- ray diffraetion （XRD）, and JEOL JSM-6700F scanning electron microscopy （SEM） equipped with an energydispersive X-ray spectroscopy （EDS）. In the as-east mierostructures, Yttrium and zinc tend to segregate at grain boundaries,     

Oxidation of Hastelloy-XR Alloy for Corrosion-Resistant Glass-Coating

The oxidation behavior of Hastelloy-XR alloy was investigated to obtain the optimum surface condition for corrosion-resistant glass-coatings. The surface morphology of oxide scales changed significantly with variation of temperatureand oxygen partial pressure (po2 ). The oxidation kinetics was mainly parabolic independent of oxidation conditions.The oxide scales were consisted of inner Cr2O3 and outer spinel layers. The phase component of spinel layers wereMn1.5Cr1.5O4 and (Mn,Ni)(Cr,Fe)2O4 for the oxygen partial pressures po2<10 kPa and po2>10 kPa, respectively.The optimum oxidation condition to obtain an oxide scale for well-adhered glass-coating to the substrate was 1248 Kand po2 =0.01 kPa for the oxidation time of 43 ks.     

噻吩在镍基非晶态合金上的吸附和脱附

应用静态吸附、动态吸附、程序升温脱附和程序升温还原等实验方法，考察了噻吩在Ni基非晶态合金上的吸附和脱附行为。常温下，噻吩分子首先吸附在清洁的Ni表面，并立刻被活化，发生氢解反应，C-S键断裂，释放出烃类部分，S留在Ni原子上。噻吩可以在Ni基非晶态合金表面发生强度不同的化学吸附。弱化学吸附的噻吩可以脱附；强化学吸附的噻吩不会脱附，而在高温下发生氢解反应。     

改性纳米TiO2光催化降解苯酚活性的研究

在装有紫外光的光催化反应器中，用锐钛型纳米TiO2为光催化剂，进行了苯酚水溶液的光催化降解性能的研究。考察了溶液的pH值、纳米TiO2用量、镍（Ni^2＋）掺杂量、苯酚的初始质量浓度等因素对苯酚水溶液光催化降解过程的影响。结果表明，在pH值为7时，苯酚水溶液的降解率达95％以上，强酸和强碱条件均不利于苯酚的降解。当TiO2用量为50mg，UV辐照40min时，200mL质量浓度为50mg／L的苯酚水溶液的降解率为96．3％；当TiO2用量为150mg，UV辐照60min时，200mL质量浓度100mg／L的苯酚水溶液的降解率为95．8％。镍掺杂增加了TiO2的光催化活性，用质量分数为10％的二氯化镍水溶液掺杂制备的复合光催化剂，苯酚水溶液的降解率比未掺杂时增加13．6％。     

诱导水解法制备微细高分散金红石型二氧化钛

采用加热TiCl4稀溶液的方式,制备晶种,将其导入一定浓度的TiCl4溶液中进行诱导水解。所得的偏钛酸经干燥、煅烧后得到分散性好,D50为1 mm以下,金红石含量为≥95%的高纯TiO2,可用于生产PTC热敏电阻等铁电陶瓷。     

不锈钢管道坡口加工的新方法

对于不锈钢管及合金钢管坡口的加工,采用以往的加工方法切割出来的坡口一般参差不平、比较粗糙,难于打磨平整。使用LGK空气等离子切割机和磁力管道切割机的组合加上一定的辅助手段,改善了不锈钢管及合金钢管的坡口加工效果,使加工出来的坡口像碳钢管一样平整,更加容易打磨组焊。文章介绍了这一新方法所用的设备、材料、切割原理以及操作过程。     

润滑油用纳米TiO2的表面改性及自修复性能研究

采用油酸对纳米TiO2进行表面改性，使其稳定分散于基础油中。利用HQ-1摩擦磨损试验机考察纳米TiO2的自修复性能，并探讨其自修复机理。试验结果表明，经改性后的纳米TiO2粉体作为润滑添加剂具有良好的分散稳定性、减摩抗磨性和自修复性。