Effect of SiC whiskers on the oxidation protective properties of SiC coatings for carbon/carbon composites

In order to effectively employ the unique high temperature mechanical properties of carbon/carbon composite substrates, SiC coatings reinforced by SiC whiskers were prepared by pack cementation method. The effect of SiC whiskers on the oxidation resistance properties of the single-layer coating and double-layer coating was investigated. SiC whiskers in the single-layer SiC coating have little effect on the anti-oxidation property but obviously improve the thermal shock property. The double-layer coating with inner-layer reinforced coating exhibits more perfect anti-oxidation ability than the double-layer coating with SiC inner-layer coating.     

Synthesis of bamboo-like carbon nanotubes by ethanol catalytic combustion technique

Bamboo-like carbon nanotubes were synthesized by ethanol catalytic combustion （ECC） technique with combustion method. Copper plate was employed as substrate, ethanol as carbon source, and iron chloride as catalyst precursor. The as-grown black powder was characterized by means of scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results show that the thinner bamboo-like carbon nanotubes have a relatively good structure that the compartment layers are more regular, while the thicker carbon nanotubes have a relatively irregular bamboo-like structure; the proposed method is simple to synthesize bamboo-like carbon nanotubes and has some advantages, such as flexible synthesis conditions, simple setup, and environment-friendly.     

短碳纤维表面化学镀铜工艺研究

实验用NaOH对短碳纤维亲水化处理，无需敏化、活化等工艺直接放入镀液中化学镀铜，研究了镀液温度、pH值和装载量对镀层质量的影响。用光学显微镜观察了镀层的表面质量。结果表明，当温度为60℃，pH值为13，装载量为0．1g／60ml时．获得的镀层光滑致密。     

中碳钢过冷奥氏体形变过程中碳的分布与扩散

利用热模拟压缩变形实验以及SEM、XRD和热磁法,研究了中碳钢过冷奥氏体变形时组织演变过程中碳原子的分布与扩散.结果表明,动态相变过程中碳的有效扩散系数与等温过程相比明显增大,相变完成时间显著缩短.在随后的片层状珠光体的球化过程中,相界以及形变过程中产生的高密度位错和空位等缺陷促进了间隙碳原子的扩散,使得球化动力学过程与等温退火相比显著缩短.渗碳体的溶解和铁素体中碳的过饱和现象得到证实,其中过饱和碳原子高度聚集在铁素体晶界和位错核心处,而不是均匀地分布在铁素体点阵的间隙位置.     

经济型低碳贝氏体复相钢的开发及应用

在实验室研究的基础上，以硅、锰为主元素，并通过热轧工艺的控制和优化，开发了一种低碳贝氏体复相热轧薄板，并在宝钢集团上海梅山钢铁公司热连轧机上进行了屈服强度450MPa级别的贝氏体热轧板的生产试制。结果表明，试验钢的平均屈服强度为500MPa，抗拉强度为590MPa，伸长率为24％，且具有良好的冲击韧性。实验钢已成功用于工程结构，能有效地降低材料消耗，减轻构件重量。     

The effect of plasma spraying power on the structure and mechanical properties of hydroxyapatite deposited onto carbon/carbon composites

This paper deals with the effect of plasma spraying power on hydroxyapatite (HA) coatings on carbon/carbon composites (C/C composites). The microstructure and phase composition of the as-sprayed coatings have been examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The shear strength of the HA coatings–C/C substrates was detected on a RGD-5 tensile testing machine. Results indicate that the melting extent and the shear strength of the coatings were evidently improved with the increasing of spraying power. Moreover, the amount of decomposed phases is increased and the content of crystalline HA of coatings was slightly changed. Observation of fracture surfaces shows that carbon fiber bundles can bond well with HA coatings using 40 kW spraying power.     

混合菌种对碳钢腐蚀行为的电化学研究

采用开路电位测量、极化曲线和电化学交流阻抗(EIS )研究了由小球菌和硫酸盐还原菌(SRB)构成的混合菌种对45#碳钢腐蚀行为的影响.结果表 明：在有限生长条件下，小球菌明显地抑制了硫酸盐还原菌的快速生长；混合菌种大幅度降 低了碳钢的腐蚀速度；该结果为更有效地防治微生物腐蚀提供了新思路.     

转炉-连铸工序生产低碳铝镇静钢中夹杂物的研究

采用添加示踪剂的方法对转炉-CAS-连铸工艺生产低碳铝镇静钢中的夹杂物进行了研究,结果表明:出钢或CAS精炼过程中炉渣与钢液作用生成的夹杂物,尺寸在30 μm以下的夹杂物很难从钢液中完全上浮排出.铸坯中的主要夹杂物为来源于钢包渣与钢液作用生成的球状夹杂物、块状Al 2O 3夹杂物.连铸坯中的全氧含量在(38～53)×10 -6之间,夹杂物的含量在 2.3 mg/kg左右,表明该工艺可以生产较高纯净度的低碳铝镇静钢坯.     

相控阵超声检测技术在碳纤维结构分层缺陷检测中的试验

以碳纤维层压结构中容易产生的分层缺陷为研究对象,采用相控阵超声检测技术进行CIVA仿真和检测试验。通过声场及缺陷的建模和CIVA仿真检测试验,得出了碳纤维层压结构分层缺陷的理想检测参数。设计制作了模拟分层试验件,并进行实际检测试验,结果表明相控阵超声技术可以有效地检测该类缺陷。     

碳离子注入纯锆后在1 mol/L硫酸溶液中的腐蚀行为

为了研究碳离子注入对纯锆耐蚀性的影响,用MEVVA源对纯锆样品进行了1×1016ions/cm2至1×1017ions/cm2的碳离子注入,注入加速电压为40 kV.用X射线光电子能谱(XPS)和俄歇电子谱(AES)分析了注入样品表层元素的价态和深度分布.透射电镜(TEM)用来观察碳离子注入样品的微观结构;碳离子注入样品后相结构的变化用掠角X射线衍射(GAXRD)来检测.纯锆注入样品随后浸入1 mol/L的硫酸溶液中,测其极化曲线以评价其耐蚀性.发现碳离子注入极大地提高了纯锆基体的耐蚀行为,剂量越高,耐蚀性越好.最后,对碳离子注入导致纯锆基体腐蚀行为发生改变的机理进行了讨论.