弥散强化Pt-3Rh合金高温性能(英文)

用粉末冶金-内氧化-烧结方法制备ZrO2弥散强化Pt-3Rh合金并测试、分析其高温性能。结果表明,Pt-3Rh合金被弥散强化以后,800℃以下的膨胀系数比Pt-3Rh大,800℃以上的膨胀系数比Pt-3Rh小;高温抗拉强度和延伸率得到提高;高温晶体结构稳定性增加;用其制备的拉丝漏板高温使用寿命与Pt-10Rh合金漏板相当。     

Zr、Y元素对Pt-10Rh合金性能的影响研究

在Pt-10Rh合金中添加少量的Zr、Y元素,利用真空充氩电弧熔炼方法制备了Pt-10Rh-0.5Zr合金及Pt-10Rh-0.5Zr-0.2Y合金。研究了合金的相结构、室温与高温力学性能以及高温抗氧化性能,观察分析了合金高温氧化及高温断口的形貌组织结构。结果表明,合金形成了由铂铑固溶体基体相与少量的金属间化合物相构成的组织结构;添加少量的Zr、Y元素大幅提高了Pt-10Rh合金的力学性能,同时Y元素还显著改善了Pt-10Rh-0.5Zr合金的高温塑性和抗氧化性能。     

High Temperature Performance of Dispersion Strengthened Pt-3Rh Alloy

用粉末冶金-内氧化-烧结方法制备ZrO2弥散强化Pt-3Rh合金并测试、分析其高温性能。结果表明,Pt-3Rh合金被弥散强化以后,800℃以下的膨胀系数比Pt-3Rh大,800℃以上的膨胀系数比Pt-3Rh小;高温抗拉强度和延伸率得到提高;高温晶体结构稳定性增加;用其制备的拉丝漏板高温使用寿命与Pt-10Rh合金漏板相当。     

TM+玻璃熔滴与铂合金的润湿性研究

用高温高真空润湿测试系统测定了TM~+玻璃熔滴与铂合金基材的接触角。结果表明,在1150~1350℃,熔滴与基材之间的接触角随温度升高而急剧下降;2种基材(Pt-20Rh和ZGS-(Pt-20Rh))的润湿转变临界温度分别为1253℃和1273℃;温度高于1300℃,采用锆弥散强化的ZGS-(Pt-20Rh)基材的接触角小于Pt-20Rh,ZGS-(Pt-20Rh)在高温下润湿性的增强不利于玻璃纤维的拉丝成型。     

Pt合金氨氧化催化剂的结构和性能

采用平行比较法研究了Pt-10Rh、Pt-4Pd-3.5Rh和Pt-12Pd-3.5Rh-RE合金以及其氨氧化催化剂的结构与性能.与传统的Pt-10Rh和Pt-4Pd-3.5Rh合金及其催化剂比较,以稀土改性的合金,即Pt-12Pd-3.5Rh-RE合金及其催化剂,具有更高的力学性能(包括室温和高温拉伸强度、持久强度和...     

硝酸工厂铂合金催化网的铂耗

铂耗和氨耗是硝酸生产的主要技术指标。在流动氧气氛模拟条件下,以及800~950℃的硝酸生产实际氨氧化环境中,Pt-Rh二元和Pt-Pd-Rh三元合金及其催化网的失重和铂耗均遵循相同的模式,即ΔW/S=Kt2/3与ΨΣ=K't2/3。工厂实际测定数据表明,在常压氨氧化法生产硝酸过程中,Pt-12Pd-3.5Rh合金催化网的铂耗为0.044 g Pt/t(HNO3),比Pt-4Pd-3.5Rh合金催化网的铂耗(0.061g Pt/t(HNO3))低28%;在中压氨氧化法生产硝酸过程中,Pt-12Pd-3.5Rh合金催化网的铂耗为0.121g Pt/t(HNO3),比Pt-5Rh和Pt-10Rh合金催化网的铂耗(0.15~0.153 g Pt/t(HNO3))低21%,而其氨耗比后者降低3%~7%。研究结果证明,在Pt-Rh合金中添加钯或在Pt-Pd-Rh合金中增加钯含量明显降低催化合金的铂耗。     

Pt—Pd—Rh合金的高温氧化

用ＴＧ热重仪测定Ｐｔ－Ｐｄ－Ｒｈ合金的挥发失重曲线，用Ｘ光电子能谱（ＸＰＳ）和溅射剥离技术确定其氧化态表层及次表层组元化学状态和浓度。结果表明合金挥发失重曲线遵循：Δｍ＝Ｋ０ｔ＾ｎ－直线失重规律。     

玻纤漏板材料PtRhAu合金研究(Ⅳ)PtRhAu合金的挥发

贵金属在高温下的氧化挥发行为是复杂的。PtRhAu 合金漏扳在生产实践中,组元的高温氧化挥发比PtRh 合金严重,其中Au 的挥发更引人注目。图1比较了几种合金在1350℃的挥发状况。在加热初期,合金以抛物线关系随后以     

3种锆合金的高温氧化行为

对Zr-A和Zr-B锆合金在700-1200℃的O_2中进行了等温氧化实验,观察了合金的氧化动力学行为和基体微观结构演变,并与低Sn的Zr-4合金作了对比.结果表明,700—1200℃氧化时,3种锆合金的动力学曲线基本服从抛物线规律,Zr-B合金在700℃氧化1200 s后速率出现转折;800℃时Zr-A和Zr-B合金的氧化速率出现转折;1000℃时3种合金动力学曲线由抛物线变为近似直线;1100℃以上氧化时,动力学曲线呈抛物线规律,未出现转折.在1100℃以上氧化时,合金成分对3种合金的高温氧化性能影响甚微.依据氧化增重数据得到了3种合金在700—1200℃氧化反应的抛物线速率常数K_p的表达式.     

池窑拉丝铂合金大漏板锥形嘴冷镦工艺及模具设计

本文阐明了采用冷镦工艺代替切削加工生产Pt-10Rh合金漏板锥形嘴的优点,对Pt-10Rh合金漏板锥形嘴零件结构特点和成形工艺进行了分析,制订了冷镦工艺方案.介绍了漏嘴坯制备处理及冷镦模具结构设计.     

可加工变形的Au-Cu-Zn-Al形状记忆合金

报道了一种新的金基形状记忆合金(Au-Cu-Zn-Al)的初步研究,结果表明,成分配比合适的合金可以用常规的方法加工变形,有典型的热弹性马氏体相变及良好的单程和双程形状记忆效应。合金的金含量可达50wt％。     

高温形状记忆合金

马氏体逆相变开始温度As点稳定在120℃以上的形状记忆合金称之为高温形状记忆合金,有多种合金系可供选择。本文综述了现有的各种高温形状记忆合金系的研究现状。     

高强度金银钯铂铜合金的性能与应用研究

介绍了金银钯铂铜合金系列的成分、组织、性能及其应用研究。其综合性能优于国内外同类材料,等体积材料的成本低于同类材料的40～80％。该系列合金适用于航空、航天和航海技术中的各类线绕传感器、电位器,电阻器的绕组和电刷以及电接触器的接点、导电环和电刷。     

我国钛及钛合金研发与进展

我国材料工作者对不同领域使用的钛合金进行了卓有成效的研究工作。经过近50年的发展,我国的钛工业在科技和生产上都取得了长足进步。概述了我国自主研发的各种钛及钛合材料,包括高温钛合金、高强钛合金、低温钛合金、耐蚀钛合金、船用钛合金、医用钛合金等。最后对我国钛工业进行了简要的展望。     

Ag-Cu-In-Sn系低熔点钎料

研究一种新型银基钎料合金Ag—Cu—In—Sn,并提供其钎焊特性和钎接头的机械性能。此钎料具有较低蒸气压和熔化温度,钎焊接头具有较高的气密性,适用于电真空、半导体及微电子器件在真空或保护气氛中无钎剂钎焊。     

Compressive training of the shape memory alloy washer

This paper evaluates the performance and engineering aspects of 44Ti-47Ni-9Nb alloy in a pretensioning washer application. Previously the behavior of this alloy has mainly been studied for tensile predeformation with wires and strips up to 1 mm thickness. The present work investigated the effect of compression deformation and different homogenization temperatures on ring-shaped washers with larger dimensions. The best results with the compression-trained washer were achieved after homogenization at 1073 K where the compression training deformation was -10.4%, the lowest applied. The deformation training was carried out at 213 K near the martensitic reaction start temperature of the material. The expansion method, applied to the commercial reference ring, seemed to be a fairly efficient training method for the studied application, even though the parallel course of the radial surfaces was poor.     

Stability of protective oxide films on Ti-base alloys

Thermodynamic calculations are performed to estimate isothermal sections of Ti-Al-O, Ti-Si-O, and Ni-Al-O phase diagrams. Very small aluminum levels (<10^–10 at. %) are needed to stabilize alumina on Ni-Al alloys. However, much higher aluminum (50%) and silicon (40%) levels are needed to stabilize alumina and silica on Ti-Al and Ti-Si alloys, respectively. These calculations suggest that the mechanism of formation of the protective oxide films on titanium-based alloys is radically different from that on nickel-based alloys. The aluminum levels needed to form a continuous film of alumina on nickel-based alloys are dominated by kinetic factors. On the other hand, thermodynamic factors appear to dominate the alloy compositions needed to form protective films of alumina and silica on titanium-based alloys. Further work is needed to evaluate any possible role of kinetic factors.     

MICROSTRUCTURE MODIFICATIONS OF WROUGHT AND CAST TiAl ALLOYS

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Corrosion of iron-, nickel-, and cobalt-base alloys in atmospheres containing carbon and oxygen

The corrosion of iron-, nickel-, and cobalt-base alloys has been studied in atmospheres containing carbon and oxygen in the temperature range 894–1366 K. It was observed that preformed Cr₂O₃ films are not effective barriers to carbon transport in atmospheres in which the oxide is not stable but that stable, growing Cr₂O₃ films are excellent barriers to carbon penetration. The presence of Fe-containing oxides on Fe-Ni-Cr and Fe-Cr alloys cause the scales to be permeable to carbon. This phenomenon was found to be sensitive to alloy surface preparation. Carbon transport through oxide scales may occur by two mechanisms: diffusion or molecular transport through physical defects. The present work has evidence of the latter but cannot rule out the former in cases where the carbon activity is sufficiently large. In gases containing CO and CO₂ in which Cr carbide is stable Cr₂O₃ was found to form at the carbide-alloy interface by oxygen transport through the carbide. In A-CH₄ Fe-Ni-Cr were found to undergo graphitization attack. The results were consistent with the formation and subsequent decomposition of metastable carbides, as proposed by Hochmann.     

Further aspects of the oxidation of binary two-phase alloys

The corrosion behavior of binary, two-phase alloys is considered in which the matrix contains mostly the less-noble metal that forms a fast-growing oxide, while the second phase is rich in a component that forms a more stable but slowly-growing oxide. It is assumed that the second phase exists as a dispersion of isolated, rod-like particles. It is further assumed that both phases form external films with no internal oxidation. It is shown that the oxidation behavior of this type of alloy depends on both the oxidation time and the size of the second-phase particles. In particular, for short oxidation times and large second-phase particles the matrix will oxidize faster than the dispersed phase, so that the dispersed particles will be only partly corroded or even incorporated into the matrix-oxide scale as unoxidized islands, forming an irregular alloy-scale interface. On the contrary, for long times and small particle sizes the two phases will tend to oxidize at approximately the same rate, leading to the formation of regular alloy-scale interfaces. The time for the transition between the two corrosion regimes depends not only on the ratio between the rate constants for the growth of the two oxides but also on the size of the dispersed-phase particles, smaller sizes producing shorter transition times. Eventually, under favorable conditions the formation of the fast-growing oxide may even stop, leading to the formation of a protective layer of the most-stable oxide.