Effect of pulegone and pulegone oxide on the corrosion of steel in 1 <Emphasis Type="Italic">M</Emphasis> HCl

The inhibitive action of pulegone and pulegone oxide toward acid corrosion of steel in molar hydrochloric acid was studied by weight loss measurements, potentiodynamic polarization, and impedance spectroscopy (EIS) methods. The pulegone is extracted starting from oil of Pennyroyal Mint (Mentha pulegium). The natural compound was found to delay the corrosion rate. The pulegone oxide is prepared by oxidation of pulegone. The inhibition efficiency was found to increase with the inhibitor content to attain 81 and 75% at 5 g dm⁻³ for pulegone and pulegone oxide. The increase in temperature leads to an increase in the inhibition efficiency of the natural compared. Correspondence: Belkheir Hammouti, Laboratoire de chimie Appliquée & Environnement, Faculté des Sciences, B.P. 717, 60000 Oujda, Morocco.     

高碘酸钾法测钢铁及合金中锰的改进建议

试样经酸溶解后,以磷酸-高氯酸混合酸(4 1)或(9 1)氧化至冒烟.在硫酸、磷酸介质中,用高碘酸钾将锰氧化到七价,测其吸光度.     

Whither tube theory: From believing to measuring

This short contribution examines the difficulties that have not yet been fully overcome in the many developments made from the simplest (and original) tube model for entangled polymers.     

钢中非金属夹杂物的金相鉴定

论述了钢中非金属夹杂物的来源，分布及对钢的质量的影响，利用它们在金相显微镜下的不同特征进行定性定量的检测，判定钢材质量。     

含铌钛钢X—52连铸坯的高温延塑性

测试了溶点－７００℃温度区间含铌钛钢Ｘ－５２连铸坯的高温延塑性。根据断口形貌、组织以及钢中析出物等的变化情况分析了该钢的脆化机理。结果表明：在熔点－７００℃温度区间，Ｘ－５２钢存在２个脆性区，熔点－１３８０℃的第Ⅰ脆性区，９２５－８２５℃的第Ⅲ脆性区。细小的ＮｂＣＮ沿奥氏体晶界的动态析出是造成第Ⅲ区脆化的主要原因。可通过向钢中添加少量的钛，以降低晶界处细小的ＮｂＣＮ的析出量，防止先共析铁素体在奥氏     

不同前处理组织的亚温淬火对PCrNiMoA钢组织和性能的影响

研究了不同前处理组织的亚温淬火对35CrNiMoA钢组织和性能的影响。试验表明:亚温淬火前,予处理组织为退火或正火态时,铁素体呈块状分布;予处理组织为淬火或调质态时,铁素体呈条状分布。对上术组织的机械性能和断裂行为作了测定,并在等强度或等冲击韧性(α_k)条件下与常规调质处理进行比较。得出:亚温处理的强韧化效果不仅取决于铁素体的量,而且主要取决于它的分布形态。经亚温淬火后,铁素体呈条状分布并且控制它的量在10%左右时,能获得最佳的强韧化效果。     

Estimation of boron isotope ratios using high resolution continuum source atomic absorption spectrometry

In the production of ¹⁰B enriched steels, the production–recycling process needs to be closely monitored for inadvertent mix-up of materials with different B isotope levels. A quick and simple method for the estimation of boron isotope ratios in high alloyed steels using high resolution continuum source flame AAS (HR-CS-FAAS) was developed. On the 208.9 nm B line the wavelength of the peak absorption of ¹⁰B and ¹¹B differs by 2.5 pm. The wavelength of the peak absorption of boron was determined by fitting a Gauss function through spectra simultaneously recorded by HR-CS-FAAS. It was shown that a linear correlation between the wavelength of the peak absorption and the isotope ratio exists and that this correlation is independent of the total boron concentration. Internal spectroscopic standards were used to compensate for monochromator drift and monochromator resolution changes. Accuracy and precision of the analyzed samples were thereby increased by a factor of up to 1.3. Three steel reference materials and one boric acid CRM, each certified for the boron isotope ratio were used to validate the procedure.     

2Cr13钢调质后奥氏体粗晶遗传及其对性能的影响

本文对汽轮机末级叶片钢2Cr13粗晶马氏体在重新加热淬火后的粗晶遗传现象进行了研究,观察了在奥氏体化时恒温形成的动力学和组织结构。讨论了在相变区的加热速度、奥氏体化温度及保温时间对奥氏体晶粒的影响。研究表明,调质后粗晶奥氏体的遗传现象,是由于沿原奥氏体晶界碳化物偏聚析出的结果。还讨论了奥氏体晶粒度对调质后力学性能的影响,扫描及透射电镜观察结果表明,调质后的力学性能,主要取决于钢中碳化物的分布及尺寸。     

Mechanics of composites with two families of finitely extensible fibers undergoing large deformations

Motivated by experimental measurements of the uniaxial response of collagen fibers, a new strain energy-density function for a solid which is finitely extensible along a preferred direction is proposed. Next, by application of a homogenization technique, the macroscopic strain energy-density function of composites with one and two families of fibers of this material embedded in a neo-Hookean matrix are determined. The resulting explicit expressions for the macroscopic strain energy-density functions are given in terms of the behaviors of the individual phases and their volume fractions. The responses of a few specific composites are investigated, revealing the lock-up surfaces of these composites. Finally, we examine the ability of the macroscopic model to capture experimentally measured stress-strain curves for the medial layer of a human abdominal aorta.     

Three generations of inorganic phosphates in solvent and water-borne paints: A synergism case

This research work is intended to compare the anti-corrosive properties of three generations of inorganic phosphate pigments in solvent-based paints and in water-borne ones, both of the epoxy type. The anti-corrosive properties of phosphate pigments were assessed by means of electrochemical techniques (corrosion potential measurements, polarisation tests, etc.), employing a steel electrode dipped into pigments suspensions. The behaviour of these pigments in anti-corrosive paints, formulated with different binders, have been studied by accelerated (salt spray cabinet and humidity chamber) and electrochemical tests (corrosion potential and ionic resistance measurements).Accelerated and electrochemical tests allowed to differentiate the anti-corrosive performance of the three phosphates studied in this research. These test are also able to detect and characterise possible synergism between the water-borne resin and the pigments.