DETERMINATION OF ACTIVITY OF AI IN SOLID Cu-Al ALLOYS

Activities and activity coefficients of Al in solid Cu-AI alloys have been determined by meansof solid electorlyte galvanic cells Al(a_1 , in alloy), Al_2O_3 | ZrO_2· Y_2O_3 | Ni, NiOand Al(a_1 , in alloy), Al_2O_3 | Na, βAl_2O_3 | Al(a_2 , in alloy), Al_2O_3     

几种镍基高温合金铝、铬涂层的抗热腐蚀性能

本文对五种高温合金及三种铝、铬涂层,用坩埚融盐全浸法,在700～900℃进行了热腐蚀试验,发现除 GH30外,其余合金上的铝涂层都比铬涂层耐热腐蚀。这可能是因为 Al_2O_3膜比Cr_2O_3 膜致密,且 Cr_2O_3 易与氧离子 O~(2-)反应,生成铬酸盐,Cr_2O_3在融盐中的溶解度也比Al_2O_3大。试验表明,GH30合金上铝涂层抗腐蚀性差是因为βNiAl 相存在大量晶界,产生沿晶内氧化。     

熔盐腐蚀过程中的内氧化、硫化对FeAl金属间化合物晶间脆性的影响

应用电化学技术及物相分析技术研究FeAl系金属间化合物在熔融NaCl-(Na,K)_2SO_4体系中的热腐蚀行为。结果表明,FeAl合金耐蚀性能较差。合金表面没有形成完整的保护性Al_2O_3氧化膜,而是遭受了严重的内氧化、硫化,且内氧化、硫化主要沿晶界发生。在局部内氧化、硫化严重区域,材料明显变脆,Zr的添加虽可改善FeAl合金的耐蚀性能,但其作用尚不足以抑制合金内硫化、内氧化的发生。而B的微量添加效果十分明显,合金表面发展出较完整的富Al_2O_3氧化层,合金不再遭受内硫化、内氧化。     

Al_2O_3涂层对高温合金K38G热腐蚀的影响

用直流反应溅射方法在镍基高温合金K38G上制备了Al_2O_3涂层,研究了涂覆(Na、K)_2SO_4的试样在1123K空气中的热腐蚀行为。实验表明,Al_2O_3涂层具有良好的粘附性,能降低K38G合金的腐蚀速率并减小腐蚀深度。本文还讨论了Al_2O_3涂层对K38G热腐蚀影响的机制。     

ACTIVATION MECHANISM OF AMORPHOUS Ni_（63）Zr_（32）La_5 ALLOY HYDROGENATION CATALYST

ＡＣＴＩＶＡＴＩＯＮＭＥＣＨＡＮＩＳＭＯＦＡＭＯＲＰＨＯＵＳＮｉ_（６３）Ｚｒ_（３２）Ｌａ_５ＡＬＬＯＹＨＹＤＲＯＧＥＮＡＴＩＯＮＣＡＴＡＬＹＳＴ￥Ｘ．Ｋ．Ｗａｎｇ．Ｎ．Ｆ．ＳｈｅｎａｎｄＧ．ＪＬｅｉ（Ｄｅｐｔ．ｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａ?..     

Parameter optimization for plasma-sprayed Al_2O_(3P)/Al composite coatings on AZ31 magnesium alloy

Al_2O_(3P)/Al composite coatings were prepared on the surface of AZ31 magnesium alloy by plasma spraying technology with mixed powders of Al and Al_2O_3. An orthogonal test containing six factors and five levels was carried out to acquire the optimum technical parameters. Microstructures and properties of the composite coatings were studied. The results show that the coatings consist of Al_2O_3 particulates distributed uniformly and Al matrix, and the interface between the particulate and matrix is continuous, compact and clean. With increasing the mass fraction of Al_2O_3 in the mixed powders, the volume fraction of Al_2O_3 in the coatings increases. The Al_2O_(3P)/Al composite coating with 14% Al_2O_3 volume fraction has more compact microstructure and more satisfactory properties.     

压铸镁合金化学镀Ni-P的沉积过程

通过扫描电镜和GDA辉光放电光谱分析仪等手段，研究了压铸镁合金化学镀Ni-P的沉积过程，结果表明镁合金化学镀的前处理使基材表面呈现孔洞结构，活化形成比较平整的疏松网孔状MgF2和AIF3层：镁合金化学镀Ni-P的初始沉积过程，首先是Ni的还原析出，并不含P；随着Ni形核数量的增多和长大，有自催化能力的Ni层产生，镍磷共沉积开始：镀层中存在铬化物、氟化物与镀液成分以及Ni的混杂层。     

Electrolytic properties and element migration in Ni-TiB_2/Al_2O_3composite cathode

With alumina sol as binder and Ni metal as sintering aids,the Ni-TiB_2/Al_2 O_3 composite cathode material for aluminum electrolysis was prepared by coldpressed sintering.The mechanical properties of the composite cathode material were measured.Its electrolytic properties were identified by a 20-A electrolysis test.Cathode samples before and after electrolysis test were measured by energy-dispersive spectroscopy(EDS).The migration behavior of various elements in the electrolysis process was studied by phase analysis.The result shows that Ni metal can effectively fill the gap between the aggregate during the sintering process,which can improve the sintering density of the composite cathode material significantly.The voltage of the 20-A electrolysis test is stable.The impurity of aluminum liquid is 0.42%.The aluminum liquid can wet the cathode surface effectively,and the Ni-TiB_2/Al_2 O_3 composite is an ideal wettable cathode material.In the process of electrolysis,the alkali elements in the electrolyte penetrate the electrode,where K goes deeper than Na.Al generated on the cathode surface will also penetrate the cathode through the gap of the composite material,while Ni in the electrode will spread into the aluminum liquid layer.     

原位生成(Al2O3+Al3Zr)p/A359复合材料的电磁制备及磨擦性能

利用A359-Zr(CO3)2体系,原位反应合成法制备(Al2O3 Al3Zr)p/A359颗粒增强铝基复合材料,在制备过程中施加低频交变电磁场进行搅拌以提高复合材料性能.干滑动磨擦试验表明,复合材料的耐磨擦性比纯基体合金明显提高,施加电磁搅拌后复合材料在较大载荷下的耐磨性提高,磨损量随载荷增加的瞬变载荷由58.8 N提高到78.8 N.磨损表面的SEM分析显示:纯基体合金为粘着磨损和剥层磨损,复合材料的磨损为磨粒磨损为主,施加电磁搅拌后的复合材料为纯磨粒磨损.     

Ti_3Al及其渗铝涂层的热腐蚀性能

采用电化学方法并结合各种物相分析技术研究了Ti_3Al金属间化合物在熔融(Na,K)_2SO_4-NaCl中的热腐蚀行为及渗铝涂层对其耐蚀性能的影响。结果表明,Ti_3Al耐热腐蚀性能较差。形成了外层为TiO_2,中间层为富铝的TiO_2-Al_2O_3复合层,内层为富铌的Nb_2O_5-TiO_2-Al_2O_3层的三层结构。渗铝涂层能在合金表面形成Al_2O_3氧化膜而明显改善Ti_3Al的耐蚀性能。     

镁合金等离子喷涂Al/Al_2O_3涂层的耐腐蚀性能

采用等离子喷涂技术在AZ31镁合金表面制备Al/Al_2O_3复合涂层,测试了镁合金及表面喷涂有Al/Al_2O_3复合涂层的镁合金试样的极化曲线,研究了没有涂层、经封孔处理和未经封孔处理的喷涂有复合涂层的镁合金三种试样在浸泡腐蚀和5%NaCl盐雾腐蚀情况下的耐腐蚀性能及其腐蚀行为.结果表明,经封孔处理的Al/Al_2O_3复合涂层镁合金试样在上述腐蚀条件下的耐腐蚀性均优于镁合金和涂层未封孔处理的试样,在浸泡试验中未封孔处理的涂层试样比镁合金腐蚀更加严重,在盐雾试验中却优于镁合金.     

TEMPERATURE DEPENDENCE UPON VISCOSITY OF Ni-P ALLOY ON AMORPHOUS FORMATION

The viscous flow of amorphous alloys near T_gis closely related to the viscosity of liquid alloys.On the basis of the measured surface tension and density for Ni-P binary alloys,the correla-tion between the viscosity of the melt and viscous flow process of the amorphous alloy is inves-tigated.The relationship between viscosity and temperature for Ni-P alloys going from liquidto amorphous solid may be described by the following formula:     

Hot Corrosion Behaviors of Ni-14%Cr Alloys in Molten Sulfate

The corrosion behaviors and mechanism of Ni-14%Cr alloys in molten salt with Na2SO4 at 1000℃ was investigated by means of XRD analysis and SEM observation. Results show that the alloys were subjected to the accelerated corrosion in molten salt and the corrosion kinetic of the alloy obeys the parabolic law. On the other hand, the corrosion-resistance of the alloy could be improved significantly by increasing of chromium content. Corrosion products may be divided into three layers, i. e. NiCr2O4, CoCr2O4, CoN...     

纳米Al2O3颗粒含量对复合镀层组织和滑动磨损行为的影响

采用电刷镀技术在45钢表面制备了纳米Al2O3颗粒增强镍基复合镀层，研究了纳米Al2O3颗粒在镀液中的含量对镀层的组织、力学性能和摩擦学性能的影响，并分析探讨了影响机理。结果表明，随着镀液中纳米Al2O3颗粒含量的增加，复合镀层的组织趋于细化，在含量为20g／L时复合镀层的硬度和耐磨性出现极值，其磨损机制也随之发生改变，这与纳米Al2O3颗粒在复合镀层中的含量和分布状态密切相关。     

电解铝液制备的7005铝合金铸态拉伸断口分析

通过室温拉伸试验研究了电解铝液制备的7005合金铸态力学性能,并采用光学显微镜观察、扫描电镜观察及能谱分析等手段对拉伸断口及其纵截面的组织形貌进行分析.结果表明,电解铝液中的Fe、Si、H2、Al2O3夹杂对7005合金铸态力学性能有显著影响.铝电解过程中生成的H2和Al2O3夹杂,是铸锭中形成疏松、夹杂的原因.电解铝液中的Fe、Si杂质元素与合金中的Mn、Mg等元素作用形成硬脆、粗大的AlFeMnSi、Mg2Si等第二相,分布于晶内以及晶界处.试样的断裂主要是由夹杂物、疏松孔洞及AlFeMnSi脆性相等裂纹源的综合作用而引起的,拉伸断裂的模式为穿晶方式的韧窝-准解理混合型断裂.     

铝青铜ZCuAl9Fe4Ni4Mn2材料的熔铸特性

选用耐腐蚀材料铝青铜ZCuAl9Fe4Ni4Mn2膻用于船用螺旋桨的制造，采用CO2-水玻璃砂造型，用中频炉和工频炉多炉熔炼，比反射炉熔炼具有含气量少，氧化烧损小的特点，一般可降低烧损率3％左右，多包底注式浇注，一次性浇注铜液质量达120t，浇注时尽量减少二次氧化，为达到螺旋桨毂顺序凝固，在浇注到冒口1／3处时，采用添加高温铜液，以利于补缩，通过以上的方法可以生产了同合格的螺旋桨。     

电沉积非晶态Ni-P合金的腐蚀行为

<正> 电沉积Ni-P合金时,只要沉积层中的磷含量大于8at％就能得到非晶态。 尽管化学镀Ni-P已作为防护工程的一种标准镀层,而电镀Ni-P台金的研究还相当有限。本工作就电镀非晶态Ni-P合金在若干酸中的腐蚀行为进行了研究。     

高温合金微晶涂层上氧化膜的修复性

本文研究了一种镍基高温合金K38G的微晶涂层上保护性氧化膜的修复性。结果表明,溅射微晶涂层上的氧化膜有优良的修复性,氧化膜剥落后,涂层仍具有优良的抗高温氧化性能。氧化膜局部小范围剥落后,表面仍能生成单一的Al_2O_3,氧化膜。氧化膜大面积剥落后,虽然生成由(Al、Cr)_2O_3与TiO_2组成的复合外氧化膜,但它具有优良的防护性和粘附性。     

Al2O3微粉表面处理及其在耐磨涂料中的应用研究

研制了一种以Al2O3为填料的耐磨涂料,利用耐磨涂料来修复铝合金部件表面的阳极氧化膜,给出了以Al2O3为填料的配方及主要性能指标,重点研究了利用共沸蒸馏法处理Al2O3微细粉体表面对涂料耐磨性的影响,并分析其成因,利用IR分析了处理前后粉体表面基团的变化,并用SEM观察粉体在树脂中的分散状态.涂层性能测试结果表明,加入经过表面处理的Al2O3后,其耐磨性、附着力明显提高,摩擦质量损失降低了43%.     

Effects of Sc, Zr and Ti on the microstructure and properties of Al alloys with high Mg content

The effects of trace Sc, Zr, and Ti on the microstructure and hardness of Al alloys with high Mg content (Al-6Mg, Al-8Mg, and Al-10Mg) were studied by optical microscope, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brinell hardness. The grain size of the as-cast alloys was refined by the addition of Sc and Zr, and it was further refined by the addition of Ti. With the same contents of Sc, Zr, and Ti, an increase in Mg content was beneficial to the refinement due to the solution of Mg into α-Al. The refined micro-structures of the as-cast alloys were favorable for Brineil hardness. Addition of Sc, Zr, and Ti to the Al-10Mg alloy results in the improve-ment of peak hardness and it is about 45% higher than that of the Al-10Mg alloy, which is due to fine precipitations of Al_3(Sc_(1-x)Zr_x), Al_3(Sc_(1-x)Ti_x), and Al_3(Sc_(1-x-y)Zr_xTi_y).