Preparation and electrocatalytic properties of tungsten carbide electrocatalysts

1　ＩＮＴＲＯＤＵＣＴＩＯＮ ｉｎ 1 5 0℃ .Ｍａａｓ[1 0 ] ａｌｓｏｍａｎｕｆａｃｔｕｒｅｄｔｈｅＨ2 Ｏ2 ｆｕｅｌｃｅｌｌｓｔａｃｋｓｗｉｔｈｔｈｅｏｕｔｐｕｔｐｏｗｅｒｕｐｔｏ 1ｋＷ ,ａｎｄｔｈｅｐｒｏｐｅｒｔｉｅｓｏｆｔｈｅａｓ ｐｒｅｐａｒｅｄｆｕｅｌ     

几种金属副在NaCl溶液中的抗蚀耐磨性能评价

应用电化学测试手段，针对20、2Cr13、QAl 9-2、QA l 10-3-15和QAl 10-4-4五种材料试件，分别测定了它们在NaCl溶液中的腐蚀电位及与QAl 9-2偶接时的电偶腐蚀电流的变化.并对几种铝青铜材料和QAl 9-2构成的摩擦副进行了摩擦磨损性能分析.结果表明，铝青铜材料的抗腐蚀性比钢好.其中QAl 10-4-4的腐蚀电位最为偏正，但它与QAl 9-2配副会对QAl 9-2产生较大的阳极电偶腐蚀；QAl 9-2与QAl 9-2相配时的电偶腐蚀最小，但其摩擦相溶性最差；而QAl 9-2与QAl 10-3-15材料副的抗电偶腐蚀能力和摩擦相溶性均佳.     

硼酸铝晶须增强Al复合材料的性能及界面结构

采用挤压铸造工艺制备出复合良好的9Al_2O_3 2B_2O_3晶须增强6061Al合金及纯Al复合材料研究表明,T6处理不能提高9Al_2O_3 2B_2O_3w/6061Al复合材料的力学性能,其原因是T6处理后复合材料中的界面反应明显加重利用透射电子显微术对此复合材料界面的观察与分析认为,界面上存在着严重的化学反应,反应物为Al_2MgO_4将制造态与T6态的界面结构对比发现,正是这种界面化学反应对材料的性能产生不利影响而在9Al_2O_3 2B_2O_3w/纯Al界面上未发现任何化学反应。界面能谱EDS成分分析结果表明,上述界面化学反应是由材料制造过程中基体合金中的Mg在界面上原子偏聚造成的     

EFFECT OF LASER SCANNING SPEED ON PHASE CONSTITUTION AND WEAR RESISTANCE OF LASER CLADDING HARD FACING ALLOY STELLITE 12

Effect of laser scanning speed on phase constitution,microstructure,microhardness and wearresistance of laser-cladding hard facing alloy Stellite 12 has been investigated by means of across-flow-type CO_2 laser of 1.5 kW.The laser-cladding layer on the alloy consists of ma-trix phase of suppersaturated solid solution γ(Co,Cr)and complex hexagonal carbideM_7C_3.Under certain condition,at higher laser scanning speed,the suppersaturated solubilityof elements increases in γ(Co,Cr),and the precipitation of the complex carbtde M_7C_3 de-creases,so the microhardness increases and the wear resistance decreases.But at slower laserscanning speed,more complex carbide M_7C_3 may precipitate,and the wear resistance may beimproved.Therefore,it is believed that the principal factor in improving wear resistance is theprecipitation of carbide M_7C_3,while increment of microhardness is the suppersaturated solu-bility of elements in matrix phase γ(Co,Cr).     

ANALYSIS OF DEPOSITED PRODUCTS AND REANODIZED POROUS LUBRICATING FILM ON A1 AFTER(NH_4)_2MoS_4 SOLUTION TREATMENT

Observation was carried out of the structure of sulphuric,oxalic or phosphoricfilm on Al after treatment of reanodizing and electrolytic depositing lubricant in(NH_4)_2MoS_4 solution,as well as of the deposited products by means of EMPA,TEMand energy spectro-scopic analysis.The deposited products are mixture of compounds ofS and Mo rather than single MoS_2 and most of them dcposited near the surface layerof the film.Some regular long pores without barrier layer occurred in the film,but theregular fine channels without relation to the structural element parameters of originalanodized film were found in the thickened barrier layer of phosphoric film.Sulphur maybe remained as Mo sulphide in the film during heating under Ar protective environment.     

Ti-13at.-％Ni-37at.-％Pd记忆合金预形变与高温形状记忆效应SCIEI

本文着重地研究了Ti-13at.-％Ni-37at.-％Pd合金的高温形状记忆效应与预形变温度的关系.该合金A_s温度是620K,具有单程形状记忆效应和双程形状记忆效应。在620—640K温度预形变,可以得到最大的形状记忆应变,这与在此温区产生的最小可逆应变能有关。     

钢的离子氮化表层中的α相微晶结构

对W18Cr4V,38CrMoAl,1Cr18Ni9Ti3钢种的离子氮化层进行了透射电镜观察,并对奥氏体不锈钢的离子氮化表层用Auger能谱进行了成分分析,由于离子轰击效应,在离子氮化表层形成了α相微晶结构,其中存在织构.在离子轰击渗扩过程中,1Cr18Ni9Ti奥氏体不锈钢的渗层的表层发生成分变化,Cr/Fe比升高,Ni/Fe比下降,所以也形成了α相微晶结构。     

制备条件对非晶态Fe78B13Si9合金的热膨胀各向异性的影响

本文研究了不同条件下形成的非易态Fe_(78)B_(13)Si_9合金在长轴和短轴方向上的热膨胀。结果表明,在所有条件下均存在热膨胀的各向异性。热膨胀系数随着冷却速度的增加而增加,但其各向异性减小;随着熔体喷铸温度的提高两者均减小。在热循环的作用下,短轴方向的热膨胀系数及其各向异性均减小;而在长轴方向的热膨胀系数却增大。我们认为热膨胀各向异性来源于原子交互作用力的方向性、原子振动频率和短程有序结构或缺陷的方向性。     

FRACTAL ANALYSES OF DIRECTIONAL SOLIDIFICATION BEHAVIOR OF A Ni-BASE SUPERALLOY

The morphology of solid/liquid interface of a directionally solidification process is describedby means of fractal analysis,and the relations among the fractal dimension of the solid/liq-uid interface,solidification rate,dendrite arm space and the phosphorus content of the test al-loys have been given.It was found that the increase of the solidification rate and the phos-phorus content of the test alloy will lead to a increase,following the regularity of exponentialfunction,in the fractal dimension of solid/liquid interface.Furthermore,by combining thefractal theory and the thermodynamic principle with the measured results,it has been provedthat the fractal dimension is not only a kind of simple geometrical parameter used in des-cribing irregular geometry,but also a state function depending the change of solidificationparameters and chemical compositions.     

基于选择性激光烧结方法的金属零件快速制造技术研究

主要研究了通过选择性激光烧结高分子原型件制造金属零件的工艺。通过采用真空压差铸造工艺。结合铸造型壳的制造，成功制造出金属零件。对基于SLS技术的精密铸造过程中的精度控制进行了研究分析，并提出了解决办法。