如何让铜金粉耐高温?

秀逗★恶魔

目前我正在做一项实验,就是通过一些化学试剂使铜金粉表面处理一下,在300度的温度下只能放置5分钟,时间再长点粉就烧掉了,没有达到我预计的效果,请问我该怎么办

funnnd

http://www.cqvip.com/QK/97035A/2007001/24032427.html
这里有一篇文章
但是看不了，你自己找找看。

wyj7506

Oxidation Resistance of Copper-Aluminum Alloys at Temperatures up to 1,000°C,
In this study, the high-temperature oxidation resistance of copper and copper-aluminum alloys in air was investigated using thermo-gravimetric analysis. Upon heating in air, copper starts to noticeably oxidize at temperatures above 400°C. It was found that as the temperature increased, more aluminum was required in order to protect the copper. Alloying with 4 wt.% aluminum leads to a remarkable improvement in oxidation resistance. The atmosphere used to heat the samples to the required test temperatures had a noticeable impact on the subsequent oxidation rates. When heated in argon before being oxidized, copper alloys with 3 wt.% and 4 wt.% aluminum showed excellent oxidation resistance with rates 1,000 times less than that of pure copper at 1,000°C. However, when these alloys were heated in air, they were much less effective at providing oxidation resistance.

INTRODUCTION

For the protection and cooling of high-temperature metallurgical reactors, various copper cooling devices are employed, including water-cooled copper fingers, panels, and tapholes. 1 The main purpose of the cooling devices is to extract sufficient heat through the wall they are protecting so a shell of frozen slag or some other frozen material is formed on the inside surface. The formation of such a frozen layer should stop or minimize reactions and erosion of the walls, extending the service life and reliability of the reactors. However, such cooling devices have problems and experience failures. One potential problem is the oxidation of the hot face of the copper cooler, leading to decreased reliability and potential failure. Failures of the cooling system may lead to run outs of molten slag, matte, or copper, causing spectacular explosions. These situations lead to lost production, expensive repairs, and dangerous working conditions. The objective of this study is to determine if the oxidation resistance of copper at high temperatures can be improved by alloying with small amounts of aluminum.2

Whittle3 established that with oxidation-resistant alloys, a surface scale forms immediately after exposure to the oxidizing gas. Upon initial exposure, the oxide of each reactive alloy component is formed in proportion to the bulk composition. Further reactions either involve outward diffusion of one of the alloying elements or inward diffusion of oxygen. Oxides with high intrinsic growth rates such as NiO, FeO, CoO, and Cu^sub 2^O, may overgrow slower-growing oxides such as Al^sub 2^O^sub 3^ and Cr^sub 2^O^sub 3^. While this overgrowth is taking place, the more stable oxides grow from isolated nuclei laterally to the point at which they may come in contact, developing a dense continuous layer.

After the initial transient stage, the overall oxidation rate becomes controlled by diffusion of a particular species through the growing oxide layer within the scale. As a consequence, the oxidation rate is often closely described by the parabolic rate law. This stage cannot last indefinitely, since at least one of the alloy components is being removed selectively and will eventually be completely oxidized.3-5 With time, scale spalling may also take place, leading to further corrosion of the alloy and the eventual need for replacement since the alloy would not be able to withstand the chemical attack of the surrounding atmosphere.

Tests on Fe-Al, Co-Al, and Ni-Al alloys5 showed that at high temperatures (T>900°C) and high (above 5 wt.%) aluminum contents, it is easy to form highly protective layers of α-Al^sub 2^O^sub 3^. However, the alumina layers spall as the temperature increases. Wood and Stott5 observed that, depending on the temperature and the aluminum content, the morphology of the oxide layers varies (see Figure 1) and can be summarized as follows:

* A compact alumina layer surrounds the alloy core, preventing further outward diffusion of the alloy components and stopping oxygen penetration

* A compact alumina layer surrounds the alloy core as in the preceding example, but the alumina layer is not as dense, and thus some oxides are randomly precipitated just beneath the Al^sub 2^O^sub 3^ layer

* A thick external oxide scale forms, made up of the host metal oxides (FeO, NiO, or CoO) followed by a layer made of a mixture of different oxides (NiO or FeO or CoO + Al^sub 2^O^sub 3^). Beneath this layer there is a region depleted in the alloying element (aluminum)

This investigation was conducted to determine if this behavior also occurred in the Cu-Al system. See the sidebar for experimental procedures.

RESULTS AND DISCUSSION

To establish under which conditions the various copper-aluminum alloys start to oxidize, using a thermogravimetric analyzer (TGA), a series of samples were heated in dry air up to 1,000°C at a heating rate of 10°C/min. As seen in Figure 2, the samples start to slowly oxidize at around 300°C. Pure copper oxidizes the fastest, and the 4 wt.% aluminum alloy the slowest. Up to about 400°C, the addition of aluminum does not significantly lower the oxidation rate. It is further observed that the 2 wt.% aluminum alloy oxidizes slower than pure copper from about 400°C to 700°C, but then reacts nearly at the same rate as copper when the temperature is increased to above 800°C. On the other hand, the 2.25 wt.% and 2.5 wt.% aluminum alloys behave in these tests very similarly to the 4 wt.% alloy, and appear to provide reasonable resistance to oxidation.
To investigate the detailed oxidization behavior of these alloys, a series of isothermal oxidation tests were carried out in the TGA. In these tests, the samples were heated in argon until temperature stabilization had been reached. After about 2 min. to 4 min. at the test temperature, air was introduced to the sample and the mass gain was recorded. The mass gain during oxidation at 800°C and 1,000°C are shown in Figure 3. As seen in Figure 3a, at 800°C the 2 wt.% aluminum alloy oxidizes at approximately the same rate as pure copper. This is very similar to the behavior shown in Figure 2 upon continuous heating in air for temperatures at and above 800°C. On the other hand, the isothermal oxidation rate at 800°C of the 4 wt.% aluminum alloy is three orders of magnitude lower than that of copper. Figure 3b compares the rates of oxidation in air of several Cu-Al alloys at 1,000°C. It is observed that alloys with 2 wt.% aluminum and less oxidize at a rate very similar to that of pure copper while the 3 wt.% and 4 wt.% aluminum alloys improve the oxidation resistance by three and four orders of magnitude, respectively. Figure 3 clearly shows that to promote good oxidation resistance at 800°C to 1,000°C, it is necessary to use at least 3 wt.% aluminum in the alloy.
One noticeable difference between the results obtained during continuous heating in air (Figure 2) with those obtained during the isothermal oxidation (Figure 3) was that when the 4 wt.% aluminum alloy was heated in air it oxidized noticeably fester than when heated first in argon before air was introduced. It is suggested that this is caused by segregation of aluminum to the surface of the alloy during heating in argon, allowing for the formation of a more dense and protective alumina layer. When heated in air, copper oxide is formed in addition to alumina since the diffusion of aluminum to the surface is slow at low temperatures. This copper oxide layer may retard the subsequent formation of a dense and protective alumina layer.

To determine how much of the actual experimental weight gain is due to the formation of alumina relative to copper oxide, after being heated in air to 1,000°C, the alloys were cooled in argon and then reduced in 80%H^sub 2^-20% Ar gas at 600°C. Since at 600°C hydrogen will not reduce Al^sub 2^O^sub 3^, any mass loss is assigned to the reduction of copper oxide. It was found that for the 2 wt.% aluminum alloy, the most oxidized alloy, the mass loss during reduction was nearly identical to the mass gain during oxidation. This means that nearly all the mass gain during the oxidation process was due to Cu^sub 2^O with basically no Al^sub 2^O^sub 3^ formation. This is reasonable since the experimental mass gain of 4.3 wt.% corresponds to a dense Cu^sub 2^O layer of about 70 µm while the maximum calculated by the diffusion of aluminum to form Al^sub 2^O^sub 3^ is only 0.6 µm. This confirms that the penetration of oxygen and the diffusion of copper outward are faster than the diffusion of aluminum toward the surface.

wyj7506

For alloys with 2.25 wt.% aluminum or more, the mass loss during hydrogen reduction corresponded to between 40% and 50% of the gain during the previous oxidation. This suggests that during oxidation upon heating to 1,000°C at 10°C/min., slightly more than 50% of the mass gain is due to oxidation of aluminum. Thus, during heating in air, the aluminum provides these alloys some oxidation resistance but a single dense layer is not formed and mixed oxidation takes place.
To confirm and extend the oxidation rates obtained in the TGA apparatus, other tests were conducted with larger samples exposed to air for extended periods of time in a muffle furnace. At 800°C, the 1 wt.% aluminum alloy oxidizes at a rate comparable to that of pure copper, while the 2 wt.% aluminum alloy has a rate of oxidation five times slower than pure copper. This lower rate appears to contradict the results from the TGA, showing that the 2 wt.% aluminum alloy oxidizes at about the same rate as copper. However, in the early oxidation stage, the 2 wt.% aluminum alloy oxidizes similarly to copper, just as in the TGA. This initial rate increment may be due to the development of the internal oxidation layer. Once such a layer has formed, the alumina that has precipitated may serve as a diffusion barrier, nearly stopping the further oxidation.

At 1,000°C, the 1 wt.%, 2 wt.%, and 2.5 wt.% aluminum alloys are unable to prevent copper oxidation. Indeed, the rates of oxidation of the 1 wt.% and 2 wt.% aluminum alloys are faster than that of pure copper. The 2.5 wt.% aluminum alloy has a rate comparable to pure copper, but as more aluminum is added to the copper, the oxidation rate decreases drastically. Both the 3 wt.% and 4 wt.% aluminum alloys oxidize at a rate three orders of magnitude slower than pure copper.

The parabolic rate constants for the different alloys tested were determined by plotting the square of the mass gained versus the time and fitting the data with the least squares method. The slopes of the resulting straight lines represent the corresponding parabolic rate constants shown in Figure 5. In order to illustrate what aluminum content is required to satisfactorily protect copper, three distinct zones of rate constants were defined. The first zone is for excellent protection. The 3 wt.% and 4 wt.% aluminum alloys fall in this category since they oxidize at an extremely slow rate at every test temperature. In addition, microscopic investigations show that no major oxidation products were formed. Other alloys that present limited excellent protection are the 2.25 wt.% aluminum up to 850°C and the 2.5 wt.% aluminum alloy up to 900°C. Up to about 700°C, the 2 wt.% aluminum alloy also provides excellent oxidation resistance. The un-alloyed copper and the 1 wt.% aluminum alloy are both basically unsuitable for any application at or above 500°C.

In the case of rate constants that are greater than 10 mg^sup 2^/cm^sup 4^/h, excellent regression was obtained with the regression coefficient R^sup 2^ above 0.95. On the other hand, for small values of the rate constants, the fit was significantly poorer. This means that with insufficient aluminum for protection, oxidation is described well by the standard diffusion barrier of the oxide layer formed. However, when sufficient amounts of aluminum are added this is no longer the case. It is proposed that as the oxidation proceeds, aluminum from the bulk region inside the oxide layer has time to diffuse outward toward the oxidizing front. This will effectively increase the local aluminum concentration and therefore also the oxidation resistance. The enrichment of aluminum may also lead to the exchange of copper oxide with aluminum to form alumina and metallic copper. In this manner, the oxidation process will deviate negatively from the parabolic rate law and instead follow more closely a cubic or logarithmic rate behavior. The concentration profiles of aluminum through the 2 wt.% and 2.25 wt.% aluminum alloys, both oxidized at 850°C during 21 h, are shown in Figure 6. Such concentration profiles confirm that when the alloy surface is enriched with aluminum, the oxidation resistance improves.
At temperatures greather than 800°C, the 1 wt.% and 2 wt.% aluminum alloys exhibited a thick external oxide scale. This scale consisted mainly of Cu^sub 2^O, and some CuAlO^sub 2^ dispersed in the external scale near to the alloy core. Some traces of CuO also were detected. This means that, at these temperatures, there is insufficient aluminum in the alloy to form a protective alumina layer, allowing copper to diffuse outward. Alloys with less than 3 wt.% aluminum will fail rapidly if they are exposed to oxidizing environments at or around 1,000°C.

The 2 wt.% aluminum alloy showed the existence of the three cases of microstructural features previously illustrated in Figure 1. At the lowest test temperature (500°C), type I morphology was present, while at 700°C, type II morphology was evident.
Finally, at and above 800°C, the third kind of microstructure was present as seen in Figure 7 for a 2 wt.% aluminum alloy oxidized at 850°C for 21 h. As the temperature increased, more copper oxide precipitates were present throughout the alloy and the thickness of the different layers contained in the oxidized samples increased. Copper oxide forms an external oxide layer beyond the alumina-rich layer. Due to insufficient aluminum, the alumina layer is not capable of preventing the continuous diffusion of copper outward to form a growing oxide layer. In the case of the 4 wt.% aluminum alloy, it basically exhibited the first and the second type of morphologies. However, the sample oxidized at 1,000°C in pure oxygen showed a small external scale without any of the other oxide layers previously cited. Such morphological features are summarized in Table I. Also shown in this table are the phases detected after performing x-ray diffraction on the oxidized samples.

ACKNOWLEDGEMENTS

Funding for this project from CONA-CyT (México) and NSERC (Canada) is greatly appreciated.

For more information, contact Gabriel Plascencia, University of Toronto, Materials Science & Engineering Department, 184 College St., Toronto, ON, Canada, M5S 3E4; (416) 978-0912; fax (416) 978-4155; e-mail g.plascencia@utoronto.ca.

References

1. J. Merry, J. Sarvinis, and N. Voerman, "Designing Modern Furnace Cooling Systems," JOM, 52 (2) (2000), pp. 62-64.

2. G. Plascencia (Ph.D. thesis, University of Toronto, Toronto, Canada, April 2004).

3. D.R Whittle, Oxidation Mechanisms for Alloys in Single Oxidant Gases," Proceedings of the High Temperature Corrosion Conference, ed. R.A. Rapp (Houston, TX: NACE, 1981), pp. 171-183.

4. G.G. Wood, "High Temperature Oxidation of Alloys," OxW. Metals, 2(1) (1970), p. 11.

5. G.G. Wood and RH. Stott, "The Development and Growth of Protective α-Al^sub 2^O^sub 3^ Scales on Alloys," Proceedings of the High Temperature Corrosion Conference, ed. R.A. Rapp (Houston, TX: NACE, 1981), pp. 227-249.

Gabriel Plascencia, Torstein Utigard, and Tanai Marín are with the Materials Science & Engineering Department at the University of Toronto in Toronto, Canada.

Copyright Minerals, Metals & Materials Society Jan 2005
Provided by ProQuest Information and Learning Company. All rights Reserved

slglnfs

7506版主写的都是英文看不懂呀？！

SLS20002003

抗氧化铜铝合金在温度高达1000摄氏度，
在这项研究中，高温抗氧化铜和铜合金在空气中进行了使用热重分析。加热后在空气中，铜开始明显氧化在温度超过400摄氏度结果发现，随着温度的增加，更需要铝，为了保护铜。合金4重。 ％铝导致了显着的改善，抗氧化。这里的气氛用来加热样本测试所需的温度有明显影响随后的氧化率。当加热的氩气被氧化，铜合金， 3重。 ％和4重。 ％铝展示了优异的抗氧化率1000倍小于纯铜在1000摄氏度然而，当这些合金在空气中加热，他们更有效地提供抗氧化。

导言

为保护和冷却的高温反应堆冶金，各种铜冷却装置采用，包括水冷式铜手指，面板， tapholes 。 1的主要目的，是冷却设备中提取足够的热量通过墙体他们是保护壳，使被冻结的炉渣或其他一些冰冻的物质形成的内表面。形成这样一个冻结层应立即停止或尽量减少的反应和侵蚀的墙壁，延长使用寿命和可靠性的反应堆。然而，这样的冷却装置有问题和经验的失败。一个潜在的问题是氧化热脸铜散热器，从而降低可靠性和潜在的故障。失败的冷却系统可能导致出局的运行熔渣，磨砂，或铜，造成壮观的爆炸。这些情况导致的生产损失，昂贵的维修，和危险的工作条件。本研究的目的是，以决定是否抗氧化铜在高温下可提高合金的少量aluminum.2

Whittle3建立与抗氧化合金，表面形式的规模后立即接触氧化气体。初次接触后，氧化反应的每一个组成部分是合金中形成的比例大部分组成。进一步反应或者涉及向外扩散之一的合金元素或向内扩散的氧气。氧化物具有高的内在增长率，如镍，铁，首席运营官，铜^分2 ^啊，可长满缓慢增长的氧化物，如铝^分2 ^ ö ^ 3 ^分和Cr ^分2 ^ ^ ö第3分^ 。虽然这种过度正在发生，更稳定的氧化物增长从孤立的原子核的横向点上，他们可能接触，建立一个密集的持续层。

在最初的短暂阶段，总体氧化率成为受扩散控制的特定物种通过增加氧化层内的规模。因此，氧化率往往是密切描述的抛物线型定律。这一阶段不能持续下去，因为至少有一个合金的成分正在有选择地去除，最终将完全oxidized.3 - 5随着时间的推移，规模剥落也可能发生，导致进一步的腐蚀合金，并最终需要自从更换合金将无法抵挡化学武器袭击周围的气氛。

试验铁铝，联合基地，以及镍铝alloys5表明，在高温下（ Ť “ 900 ° C ）和高（超过5重。 ％ ） ，铝含量，很容易形成保护层高度的α -铝^分2 ^ ö ^ 3 ^分。但是，氧化铝层剥落的温度升高。木材和Stott5指出，根据温度和铝含量，形态的氧化层不同（见图1 ） ，可归纳如下：

*一个紧凑的氧化铝层围绕合金核心，防止进一步的向外扩散的合金成分和阻止氧渗透

*一个紧凑的氧化铝层围绕核心合金在前面的例子，但氧化铝层并不密集，因此，一些氧化物沉淀随机之下的Al ^分2 ^ ö ^ 3 ^分层

*一个厚厚的外部氧化氮规模的形式，由东道国金属氧化物（氧化铁，氧化镍，或兼首席运营官） ，其次是层制成的混合不同的氧化物（或铁镍或首席运营官+基地^分2 ^ ^ ö第3分^ ） 。下面这一层有一个贫地区的合金元素（铝）

这项调查是为了确定这种现象也发生在铜铝系统。见栏的实验程序。

结果和讨论

建立在什么条件下的各种铜铝合金氧化开始，利用热分析仪（热） ，一系列的样本加热干燥的空气上升到1000摄氏度的升温速率10 ℃ /分钟。正如图2 ，样品开始缓慢氧化在约300摄氏度纯铜氧化速度最快，和4重。 ％铝合金最慢的。直至约400 ° C时，除了铝并不显着降低氧化速率。这是进一步指出，第2重。 ％铝合金氧化低于纯铜从约400 ℃至700 ℃ ，但随后的反应几乎以同样的速度铜当温度上升到高于800摄氏度另一方面，在2.25重。 ％和2.5重。 ％铝合金的行为在这些测试非常类似4重。 ％合金，似乎提供了合理的抗氧化。
调查的详细氧化行为的这些合金，一系列的恒温氧化试验中进行热。在这些测试中，样品在氩气加热温度稳定，直至达成了。经过约2分钟。至4分钟。在试验温度，空气被介绍给样品和大众增幅记录。大众氧化过程中获得800 ° C和1000 ° C是如图3所示。正如图3A条，在800 ℃的2重。 ％铝合金氧化大致相同率为纯铜。这是非常相似的行为如图2所示持续加热后在空气中的温度及以上的800摄氏度另一方面，在恒温氧化率在800 ℃的4重。 ％铝合金是三个数量级低于铜。图3B款率比较氧化空气中的几个铜铝合金在1000摄氏度它指出，合金2重。 ％ ，铝和减少氧化的速度非常相似的纯铜，而3个野生。 ％和4重。 ％铝合金提高抗氧化能力由三个和四个数量级，分别为。图3清楚地表明，促进良好的抗氧化性能在800 ℃至1000 ℃ ，这是必须使用至少3个重。 ％ ，铝的合金。
一个明显的差别所取得的成果不断在空气中加热（图2 ）这些期间取得的恒温氧化（图3 ）是，当4重。 ％铝合金加热空气氧化明显恶化时，比第一次加热氩气在空气中介绍。有人建议，这是造成隔离的铝表面合金在氩气中加热，从而形成一个更加致密氧化铝保护层。当加热空气中，氧化铜形成除了因为氧化铝的扩散铝的表面是缓慢的低温。这种氧化铜层可延缓随后形成一个致密的氧化铝保护层。

要确定有多少实际的实验体重增加是由于氧化铝形成相对氧化铜后，在空气中加热到1000 ℃ ，合金在氩气冷却，然后减少80 ％ H ^分2 ^ - 20 ％的氩气在600摄氏度由于在600 ℃的氢不会减少铝^分2 ^ ö ^ 3 ^分，任何质量损失分配给减少了氧化铜。有人发现， 2重。 ％ ，铝合金，最氧化合金，大众在减少损失几乎是相同的增重过程中氧化。这意味着，几乎所有的大规模增益在氧化过程是由于铜^分2 ^ ö基本上没有与基地^分2 ^ ^ ö分3 ^的形成。这是合理的，因为大规模的实验获得了4.3重。 ％ ，相当于密集的铜^分2 ^ ö层约70微米，而计算的最大的扩散，形成铝铝^分2 ^ ^ ö第3分^只有0.6微米。这证实氧渗透和扩散的铜外向的速度超过了扩散对铝的表面。

SLS20002003

对于合金含量2.25 ％，铝或更重要的是，在质量损失减少氢之间相对应的40 ％和50 ％的涨幅在过去的氧化。这表明，在氧化后加热到1000摄氏度在10 ℃ /分钟。 ，略多于50 ％的增重是由于氧化的铝。因此，在空气中加热，铝提供这些合金的一些抗氧化性能，但单一的致密层是没有形成和混合氧化发生。
为了确认和扩展的氧化率获得的大动脉转位器具，其他试验进行了较大的样品暴露在空气中长时间在马弗炉。在800 ℃ ， 1重。 ％铝合金氧化的速度媲美的纯铜，而第2重。 ％铝合金的氧化速度5倍慢于纯铜。这种低利率似乎矛盾的结果，大动脉转位，显示出2重。 ％铝合金氧化在同一率为铜。然而，在氧化初期阶段，二重。 ％铝合金氧化铜同样，就像在大动脉转位。这初始速率增加的原因可能是发展的内氧化层。一旦这种层已经形成，氧化铝已沉淀可作为扩散障碍，几乎停止进一步氧化。

在1000 ℃ ， 1重。 ％ ， 2重。 ％和2.5重。 ％铝合金无法防止氧化铜。事实上，氧化率的1重。 ％和2重。 ％铝合金是快于纯铜。 2.5重。 ％铝合金有相比率纯铜，但随着越来越多的铝添加到铜，氧化率大幅度下降。这3个野生。 ％和4重。 ％铝合金氧化的速度在三个数量级低于纯铜。

抛物线速率常数的测试不同的合金，测定了策划平方米的大规模上涨与时间和数据拟合的最小二乘法。斜坡所产生的直线代表了相应的抛物线速率常数如图5 。为了说明什么是铝含量要求抓好保护铜，三个不同地区的速率常数的定义。第一区是很好的保护。 3重。 ％和4重。 ％铝合金属于这一类，因为它们氧化在一个极其缓慢的速度在每一个测试温度。此外，微观的调查表明，没有重大的氧化产物形成的。其他合金，目前有限的出色保护的野生2.25 。 ％铝高达850 ° C和2.5重。 ％ ，铝合金上升至900摄氏度直至约700 ° C的含量2 。 ％铝合金还提供了极好的抗氧化性能。联合国合金铜和1重。 ％铝合金都基本上不适合任何应用程序或超过500摄氏度

在速率常数大于10毫克^燮2 ^ /平方公分燮4 ^ / h时，出色的回归得到的回归系数R ^ 2 ^燮0.95以上。另一方面，小价值的速率常数，适合显着穷。这意味着，没有足够的铝保护，氧化描述以及标准的扩散阻挡层的氧化层形成。然而，当足够数量的铝增加，这是不再是这种情况。有人建议，作为收益的氧化，铝的大部分区域内的氧化层有时间外向弥漫对氧化前线。这将有效地提高当地的铝浓度，因此，还抗氧化。丰富的铝也可能导致交流的氧化铜与铝形成氧化铝和金属铜。在这种方式下，氧化过程将产生不利偏离从抛物线型定律，反而更密切的后续立方或对数率的行为。该浓度分布的铝通过2重。 ％和2.25重。 ％ ，铝合金，氧化都在850 ℃时21小时，列于图6 。这种浓度分布确认，当合金表面是丰富的铝，抗氧化性能得到改善。
greather温度超过800 ℃ ， 1重。 ％和2重。 ％铝合金展示了厚厚的外部氧化氮规模。本表主要包括铜^分2 ^ O和一些CuAlO ^分2 ^分散在附近的外部规模的合金的核心。一些铜的痕迹也被发现。这意味着，在这些温度下，没有足够的铝制合金中形成氧化铝保护层，使铜弥漫离港。合金不少于3重。 ％ ，铝将无法迅速，如果他们暴露在氧化环境，或约1000摄氏度

2重。 ％铝合金表明存在3例显微特征表明以前在图1 。在测试的最低温度（ 500 ℃ ） ， I型形态存在，而在700 ℃ ， II型形态是显而易见的。
最后，在以上800 ℃ ，第三类的微观结构是目前看到的图7为2重。 ％氧化铝合金在850 ℃ 21小时随着温度的增加，更多的铜氧化物沉淀在场整个合金和厚度的不同层次中所载的氧化样品增加。氧化铜形式的外部氧化层以外的氧化铝层丰富。由于不够铝，氧化铝层是不是能够防止连续扩散的铜外向，形成氧化层越来越多。在4重。 ％ ，铝合金，它基本上展示了第一和第二类型的形貌。然而，氧化样品在1000 ° C在纯氧显示一个小规模的外部没有任何其他氧化层曾引用。这种形态特征总结表一还显示在此表中的各个阶段都表演后发现X -射线衍射对氧化样品。

致谢

资助该项目由刀豆，色素（墨西哥）和NSERC （加拿大）的高度赞赏。

欲了解更多信息，联络加布里埃尔森夏，加拿大多伦多大学材料科学与工程系， 184学院街，多伦多，对，加拿大， M5S 3E4 ; （ 416 ） 978-0912 ，传真： （ 416 ） 978-4155 ，电子邮件： g.plascencia @ utoronto.ca 。

参考文献

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2 。湾森夏（博士论文，加拿大多伦多大学，加拿大多伦多， 2004年4月） 。

3 。梁智惠特尔，氧化机制的合金在单一氧化剂气体， “诉讼的高温腐蚀会议，编辑。类风湿性关节炎拉普（休斯敦，得克萨斯州：曼， 1981年） ，页。 171-183 。

4 。 G.G.伍德， “高温氧化的合金， ” OxW 。金属， 2 （ 1 ） （ 1970年） ，页11 。

5 。 G.G.木材和RH 。斯托特“的发展和成长的保护α -铝^分2 ^ ^ ö分3 ^合金秤上， ”议事的高温腐蚀会议，编辑。 R.A.拉普（休斯敦，得克萨斯州：曼， 1981年） ，页。 227-249 。

加布里埃尔森夏，托尔施泰因Utigard ，并Tanai马林是与材料科学与工程系多伦多大学在加拿大多伦多。

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