Ti/nano-TiO2-Pt复合电极催化甲醇氧化的研究

采用溶胶-凝胶法(sol-gel)制备纳米TiO2(Ti/nano-TiO2)膜电极,再用电沉积法在纳米TiO2膜上修饰Pt微粒,制成Ti/nano-TiO2-Pt复合电极.用循环伏安法研究了纯Pt丝电极和Ti/nano-TiO2-Pt电极对甲醇氧化的电催化活性以及稳定性.结果表明:对甲醇氧化,复合电极比Pt丝电极具有更高的催化活性,且对甲醇氧化中间产物CO的吸附量少,因而不易中毒;复合电极载铂量达到一定值时,电极具有最强的催化活性.     

Pt丝型芯撑对DD5单晶高温合金组织和性能的影响

以DD5二代单晶高温合金为研究对象,通过在单晶薄板中插入Pt丝型芯撑模拟研究型芯撑对于涡轮叶片基体组织和成分偏析的影响,同时测试插入Pt丝型芯撑后DD5合金薄板的典型性能,明确型芯撑对于合金性能的影响规律。结果表明：Pt丝型芯撑与DD5合金基体熔接效果好,无明显异质界面,Pt丝完全合金化,其组织与DD5合金基体组织一致,未形成新相。Pt丝型芯撑的插入对于DD5合金基体组织的影响不大,但导致合金元素偏析程度升高。此外,Pt丝型芯撑的插入对DD5合金薄板的室温拉伸、870℃拉伸及1093℃/158MPa持久性能未产生明显负面影响,合金的断裂模式为枝晶间开裂,裂纹沿碎裂的碳化物及碳化物与基体界面处萌生并扩展。     

纳米氧化锆对铂性能的影响

用锆盐的前驱物(ZrO(OH)2)胶体与纯Pt均匀混合，经加工后，纳米ZrO2均匀分布于Pt基体中，使Pt的室温抗拉强度得到很大提高。同时，纳米ZrO2弥散强化Pt的高温瞬时强度及高温持久强度明显高于纯Pt。纳米ZrO2弥散强化Pt的晶粒随着纳米ZrO2含量的增加而细化，且再结晶温度随之提高。     

铂铑10-铂热电偶的脆断失效分析

对在还原性气氛使用下的铂铑10-铂热电偶发生的偶丝脆断现象进行分析.运用金相显微镜和电子探针对铂铑10-铂热电偶的偶丝焊点及偶丝断口进行检测后认为:脆断失效的根本原因在于Si与Pt作用形成Pt5Si2低熔点共晶物,使偶丝因局部熔点降低而熔化,随之发生脆断.     

铂丝与银丝的火焰钎焊

某科研单位研制某仪器时,需要φ0.5mm铂丝与φ0.5mm银丝对接。铂丝与银丝的熔点、沸点、线膨胀系数如下: 熔点:Pt:1769℃,Ag:960.8℃;沸点:Pt:4530℃,Ag:2210℃;线膨胀系数(0℃～100℃):Pt:8.9×10~(?)/℃,Ag:19.7×10~(-6)/℃。     

PtRh_(10)/Pt 及 PtRh_(13)/Pt热偶丝性能检测

为制定出我国的测温热电偶的系列产品,尽快与 IEC(国际电工委员会)的标准取得一致,以利对外贸易和国际上技术交流,必须解决检定分度 IEC 铂铑系列的标准器问题。云南温度仪表测试中心站对冶金部贵金属研究所生产的 PtRh10/Pt 热电偶丝、PtRh13/Pt 热电偶最新丝材进行测试考核。主要考核其稳定性(1100℃及1400℃)及热电特性。由于我国目前还没有标准 PtRh13/Pt 热电偶检定规程,该热偶丝在考核鉴定过程中的试验方法、工艺处理、制作分度及仪器设备要求,基本上参照中国计量科学院过     

挤压-拉拔的纯镁丝材在人工模拟体液中的腐蚀行为(英文)

研究了挤压-拉拔的纯镁丝材在人工模拟体液和0.9%NaCl溶液中的腐蚀行为。通过测量纯镁丝材在人工模拟体液中的平均腐蚀速率和腐蚀后溶液的pH值来研究其腐蚀规律。通过扫描电子显微镜观察纯镁丝材腐蚀后人表面形貌,发现纯镁丝材的腐蚀机理为点腐蚀。而且,纯挤压拉拔的纯镁丝材在0.9%NaCl溶液中的腐蚀行为表明,丝材的晶粒越细小丝材所表现出来的耐腐蚀性能越好。     

聚四氟乙烯热压器与贵金属样品的溶解

采用梯形密封杯溶料,成功地解决了Pt—Ir、Pd—Ir、Pt—Rh夏纯Rh等难溶贵金属及合金样品的溶样问题。     

甲烷检测中的纳米结构钯

在有害可燃气体应用中,应优先考虑其检测。对天然气工业,主要要检测的是甲烷。检测可燃气体的一种常用方法是Pellistor传感技术。Pellistor可检测气体在燃烧中的温度升高。专用的Pellistor结构有一根细Pt丝线圈埋在难熔板下,板上承载有催化剂(通常为Pd)。Pt丝加热催化剂使其到工作温度,当催化剂燃烧时,催化剂温度上升,其电阻的变化使Pt丝可检测到过热情况。然而,因Pt丝很细(10μm～50μm)的Pellistors易损坏,且装置的耗能高(120mW～150mW),所以不得不特殊制作。近来制作的微机械“热板”二维灵敏感结构,其板上有SiO2或SiN受蚀薄层,层…     

强化型纯铂材料性能研究

针对纯铂微细丝的加工难点,探讨了在有微量元素R存在时强化型纯铂微细丝的原料纯度和微观形貌,以及微细丝的研制方法,并就强化型微细丝和海绵铂微细丝的有关性能进行了对比;研制的强化型纯铂微细丝,其热电性能符合国家标准,满足用户需求。     

铸态金铂合金的成分偏析调控研究

金铂合金以高密度、高硬度、良好的导电导热性能及超低剩磁矩和磁化率在航空领域中作为验证质量得到了广泛应用，但金铂合金制备过程中存在着极为严重的成分偏析现象。本文主要针对此问题开展研究工作，采用高频感应炉和喷铸两种工艺制备金铂合金样品，通过多道次轧制并结合固溶工艺研究金铂合金的成分偏析的分布状态，结果表明，高频感应炉制备的金铂合金成分偏析较为严重，喷铸工艺成功实现对金铂合金成分偏析的调控，通过EDS能谱分析发现喷铸工艺较感应熔炼工艺可将成分偏差由20%控制为1%。随后利用Anasys fluent计算模拟得到金铂合金两种不同制备工艺下凝固过程中的温度场、流场及溶质场分布。     

磁兼容Au-25Pt合金的组织结构及综合性能

Au-Pt合金具有优异的MRI磁兼容性、良好的生物兼容性、高的耐蚀性等优点,在医用材料领域具有巨大的应用前景。采用X射线衍射仪、金相显微镜、维氏显微硬度仪和综合物性测量系统等,研究冷加工过程Au-25Pt合金丝材的组织结构演变及其对体积磁化率和维氏硬度的影响,为制备综合性能优异的Au-Pt合金探索有效途径。结果表明,固溶处理后的Au-25Pt合金为面心立方结构的单相固溶体,经30%~70%冷变形后,没有其它相产生。冷加工变形显著增加了Au-25Pt合金的维氏硬度,尤其在冷加工初期(<30%变形量),但对磁化率影响很小。冷变形Au-25Pt合金不仅具有接近人体组织的体积磁化率(?8.5×10^?6),还有较高的维氏硬度(HV0.1=160)。     

碳载金铂双金属催化剂催化活性研究

采用KBH4做还原剂、PVP做保护剂,化学法一步合成Au-Pt合金纳米粒子,应用UV-Vis、TEM、XRD等手段对其进行了表征.将所合成的合金纳米粒子负载在碳黑上,获得Au-Pt双金属碳载催化剂,应用循环伏安法(CV)检测了催化剂对甲醇的电催化氧化活性.研究表明,Au-Pt/C催化剂的催化活性明显高于Pt/C的,说明...     

Preparation and electrocatalytic property of Au-Pt/SnO2/GC composite electrode

Au-Pt/SnO2/GC composite electrode was prepared by self-assembling Au-Pt nanoparticles on SnO2 film, which was deposited on actived glassy carbon (GC). Atomic force microscopy (AFM) and scanning electron microscopy (SEM) images revealed that dense and uniform Au-Pt particles with 25-nm diameter were dispersed on SnO2 film. X-ray photoelectron spectroscopy (XPS) results proved that there was an interaction between Au-Pt nanoparticles and SnO2 support. Electrochemical experiments showed that Au-Pt/SnO2/GC composite electrode had a good electrocatalytic activity to the oxidation of methanol.     

Au-Pt双金属纳米粒子的制备及其电催化性质

在PEG10000/Vc/HAuCl4体系中,用Vc还原HAuCl4制备金纳米粒子,以所制备的金纳米粒子为晶种,通过控制HAuCl4与H2PtCl6的质量比,制备不同Pt/Au比的双金属纳米粒子,并进一步研究其对H2O2电化学氧化的催化作用。紫外-可见光谱(Uv-vis)、透射电子显微镜(TEM)、选区电子衍射(SAED)、X射线粉末衍射(XRD)等实验结果表明：Au-Pt双金属纳米粒子为面心立方结构的合金。用循环伏安法对Au-Pt双金属纳米粒子修饰的玻碳电极的电化学性能进行测试,结果表明：Au-Pt双金属纳米粒子对H2O2电化学氧化有一定的催化作用。催化效率随Au-Pt双金属粒子中Pt含量的增加而增加。     

The influence of the microstructure of high noble gold-platinum dental alloys on their corrosion and biocompatibility in vitro

The aim of this work was to compare the microstructures of two high noble experimental Au-Pt alloys with similar composition with their corrosion and biocompatibility in vitro. We showed that Au-Pt II alloy, composed of 87.3 wt.% Au, 9.9 wt.% Pt, 1.7 wt.% Zn and 0.5 wt.% Ir + Rh + In, although possessing better mechanical properties than the Au-Pt I alloy (86.9 wt.% Au, 10.4 wt.% Pt, 1.5 wt.% Zn and 0.5 wt.% Ir + Rh + In), exerted higher adverse effects on the viability of L929 cells and the suppression of rat thymocyte functions, such as proliferation activity, the production of Interleukin-2 (IL-2), expression of IL-2 receptor and activation — induced apoptosis after stimulation of the cells with Concanavalin-A. These results correlated with the higher release of Zn ions in the culture medium. As Zn²⁺, at the concentrations which were detected in the alloy’s culture media, showed a lesser cytotoxic effect than the Au-Pt conditioning media, we concluded that Zn is probably not the only element responsible for alloy cytotoxicity. Microstructural characterization of the alloys, performed by means of scanning electron microscopy in addition to energy dispersive X-ray and X-ray diffraction analyses, showed that Au-Pt I is a two-phase alloy containing a dominant Au-rich α₁ phase and a minor Pt-rich α₂ phase. On the other hand, the Au-Pt II alloy additionally contained three minor phases: AuZn3, Pt₃Zn and Au_1.4Zn_0.52. The highest content of Zn was identified in the Pt₃Zn phase. After conditioning, the Pt₃Zn and AuZn₃ phases disappeared, suggesting that they are predominantly responsible for Zn loss, lower corrosion stability and subsequent lower biocompatibility of the Au-Pt II alloy.     

Preparation and electrocatalytic property of Au-Pt/SnO<Subscript>2</Subscript>/GC composite electrode

Au-Pt/SnO₂/GC composite electrode was prepared by self-assembling Au-Pt nanoparticles on SnO₂ film, which was deposited on actived glassy carbon (GC). Atomic force microscopy (AFM) and scanning electron microscopy (SEM) images revealed that dense and uniform Au-Pt particles with 25-nm diameter were dispersed on SnO₂ film. X-ray photoelectron spectroscopy (XPS) results proved that there was an interaction between Au-Pt nanoparticles and SnO₂ support. Electrochemical experiments showed that Au-Pt/SnO₂/GC composite electrode had a good electrocatalytic activity to the oxidation of methanol.     

高锰钢与高碳钢焊接专用焊条的研制

采用Ｈ０８Ａ焊芯,通过药皮过渡有益合金的方式,研制高锰钢辙叉与高碳钢钢轨焊接的专用焊条,通过相关标准检验,达到了使用要求。     

Microstructural analyses of two high noble gold-platinum alloys before and after conditioning in a cell culture medium

Microstructures of two high noble experimental Au-Pt alloys were compared before and after conditioning for biocompatibility, in order to identify phases and microelements responsible for the alloys’ corrosive behaviour. Microstructural characterization was carried-out by optical and scanning electron microscopy, in addition to energy dispersive X-ray analysis. X-ray diffraction was applied to determine the phases’ composition and their contribution in the alloys. Additionally, simultaneous thermal analysis was used to identify the temperatures of phase transformations. An overall assessment before conditioning showed that Au-Pt I is a two-phase alloy containing a dominant Au-rich α₁ phase and a minor Pt-rich α₂ phase, while the Au-Pt II alloy contains in addition three minor phases: AuZn₃, Pt₃Zn and Au_1.4Zn_0.52. The highest content of Zn (up to 6.76 wt.%) was detected in the Pt3Zn phase. After RPMI cell culture medium conditioning, the Pt3Zn and AuZn3 phases disappeared, suggesting that they are predominantly responsible for Zn loss and the lower corrosive stability of the Au-Pt II alloy.     

药芯焊丝再热裂纹试验研究

介绍了一种圆筒状试样研究再热裂纹倾向的试验方法,通过该方法评价了国外公司研制的1Cr-0.5Mo耐热合金钢用药芯焊丝的再热裂纹倾向。为便于了解该种材料的再热裂纹倾向,将化学成分和力学性能相当的国产R307焊条的再热裂纹倾向与之进行对比。通过该方法的研究,为焊丝类焊接材料再热裂纹倾向研究试验方面进行了有益的探索。