外文翻译-半连不锈钢AISI 304的等离子膏剂渗硼处理

Plasma paste boroniding treatment of the stainless steel AISI 3041.IntroductionAA3003 alloys in recent years, the development of surface treatment process has been extensive research to improve the application of stainless steel under high temperature and pressure wear and oxidation resistance. Stainless steel surface treatment methods available, including nitrogen 2, carburizing, plasma coating, boron penetration In particular, the boride is boron penetration and diffusion into the surface of the boride layer (hardness (HV) between in 1300-2100) of the surface treatment. Boride layer has excellent heat resistance and corrosion resistance, and boride have been applied to improve the valve, burners, nozzles and other surface properties, when they are exposed to high temperature and pressure when in the water and oil.Recently, however, improved technology such as plasma Boronizing infiltration process has been extensively studied, because the traditional boronizing process, such as the official salt-bath and gas nitriding boron-boron will appear, such as environmental pollution, toxic, explosive nature of the problem.Plasma boronizing has many advantages over traditional boronizing process. For example, expect a high energy efficiency as a source of high-energy plasma to be used in plasma boronizing process, and distortion can be minimized, because the processing temperature is relatively lower than the traditional process. However, plasma boronizing process also has its own limitations. BZH6 and BC13 gas was used as a boron source gas, but gas is relatively expensive and toxic, explosive. In a vacuum chamber by boron chloride corrosion is another serious problem for the plasma boronizing.In this study, as the development of a solution to the problem mentioned above and more in the process of boron penetration in one attempt, involving the use of amorphous boron and borax (Na2B4O7) cream is a simple process of plasma Pasty boronizing methods have been designed, the best plasma boronizing paste has conducted a survey of process conditions, thus the formation of boride layer method has certain characteristics2.ExperimentalThe real AISI304 stainless steel specimens (diameter 15 mm, thickness 2.5 mm) was used for this test. Sandpaper (# 1200), after polishing the surface of the sample specimen, clean off the dirt after the samples are brought into the laboratory, in the H2 atmosphere for sputter cleaning of the specimen is the first to be carried out. In Ar: H2 (2:1) gas environment, with different proportions of boron and borax mixture of boron penetration agents do boronizing plasma treatment began, in 1023,1073,1123,1173 and 1223 K several heated at different temperatures for up to 7 hours. Using micro-scanning electron microscope (Hitachi 5-2400) to study its microscopic structure, accelerating voltage of 20 kV electron microprobe analysis done. Vickers hardness was measured using a 0.1 kg force load, using the average of seven readings. CuK-ray diffraction X-ray diffraction analysis was used. Plasma Pasty boride of apparatus and details of other trials in reference 6 using description.3.Results and discussion3.1 Cream mixture ratio of boride layer formationFig1 The effect of various ratios of amorphous boron and borax mixturethickness of the boride layer.Fig.1 shows the proportion of paste with different boride in the 1123 K temperature insulation 1.5 hours after the boride layer thickness. Observed with the mass fraction of 20% and 70% of borax to form a thick boride layer. And with the mass fraction of 100% of amorphous boron to form any measurable thickness of boride layer is not observed, which may be attributed to the penetration of boron in plasma during the amorphous boron as the melting point due to surface diffusion of the lack of activity of boron.When the mass fraction of borax to 20%, the active form of the boride layer was observed. During the infiltration of boron, boron atoms, B0, is cream of the boron hydride (BnHm) of decomposition, and the boron atoms into the molten borax or B0 glow discharge in the active boron atoms B +1. Finally, the boron atoms, B +1, proliferation, and iron reaction, and then the formation of boride layer. With the mass fraction of 30% and 70% of the boron paste of borax boride layer formation was also observed, which may be attributed to the effective mechanism of liquid electrolyte, when the borax with the cream in the increase in the number, the mobility of molten borax increase the time.Moreover, the mass fraction of 40 and 55% of the paste, when the slow rate of boride was observed, as shown in Figure 1. Presumably, for including gas, electrolysis, electrolysis, etc., a variety of non-liquid boronizing mechanism, the active ingredient in this range will be difficult for some reason, the need for further investigation.Figure 1 stainless steel boride layer thickness less than mild carbon steel, which confirms previously reported results 7,8. Not only because of the stainless steel surface has a protective layer, but also in chrome, nickel boride on the surface but also the protective layer, they form with the grain boundary, thereby preventing the diffusion of boron 7,8. It was also pointed out that, due to the increase in the number of boron, paste becomes excessive, adhesive on the surface when the plasma samples Pasty boronizing began, leading to the recovery of this cream is very low. Considering the high cost of boron, therefore infer plasma Pasty Pasty boride components with the best mass fraction of 30% amorphous boron and 70% of borax.3.2Effect of temperature and time on the rate of formation of the boride layerFig. 2. Relation between the boroniding temperature and times on theFigure 2 shows the temperature and time on the boride boride layer depth. According to the parabolic theory, with the infiltration time and temperature increased boron, boride layer depth will also increase. This shows that the boride layer formation rate becomes slow as time increases boron penetration. This can be explained by the fact that: the formation of boride layer on the surface of the Ni-rich layer below and chromium-rich layer plays the role of diffusion barrier, inhibit the activity of boron diffusion. Further explanation will be given later in the article.3.3 Changes in cross-section hardness distributionFig. 3. Hardness curves of AISI 304 boronized for various times at 1173 K.Plasma boride specimens in 1023,1073,1123 K, holding seven hours to get the boride layer thickness can not be measured, and their hardness measurement is impossible. In 1173 and 1223K temperature plasma boronizing, in any case, the formation of 30 to 40 microns thick boride layer; boride samples of plasma for 7 hours at 1223K cross-section hardness measurement results are summarized in Figure 3 on. Boride in plasma 7 hours after the specimens found on the maximum depth of the nitrided layer of 45 microns, and the maximum hardness of 1800 to 2000 of the nitrided layer.3.4 Boride layer cross-section microstructure and composition analysis ofFig. 4. Microstructure of the boride layer.For AISI304 stainless steel processing in 1023 1223K 3,5,7 hours of boride layer cross-sectional study of micro-structural inspection found that with the infiltration of growth temperature and time of boron, followed by growth of boride layer thickness. Boronizing carbon steel in the normal tooth structure observed in the stainless steel observed in the boride not. On the contrary, as shown in Figure 4, in 1173K after 3 hours of boride boride layer of stainless steel flat structure emerged.Plasma cross-section of boride specimens show a layer of micro-structure of boride layer, Ni-rich layer, chromium-rich layer, as well as the matrix, and other researchers observed results. Figure 4 electron probe composition analysis of each region. The results showed that boride layer containing about 4 wt nickel, base and about 7.5 Ni. This explains the boride layer under the Ni-rich layer formation. During the plasma boronizing, when excess nickel boride layer needs to spread to the substrate, the Ni-rich layer in between boride layer and matrix formation. In addition, the observation of Figure 4 in the Ni-rich layer under the chromium-rich layer (about 28 wt% of chromium). According to the current electron microprobe analysis of linear boron, boron penetration in the plasma during the boride layer observed a high degree of boron concentration, boron-rich area of high concentration of chromium was also detected, suggesting that this region has a large number of chromium boride formation.In addition, Katagiri observed in the boride layer with small pores and boron trichloride, hydrogen for the formation of iron boride boride layer similar to the pores. Because these pores on the mechanical properties of diffusion layer is detrimental, so a lot of holes to determine the formation mechanism of these studies have been carried out. To date, the boron in the boride layer in the heterogeneous distribution of boride layer is generally considered the main reason for the formation of the pores. According to reports, the effective diffusion annealing processing method to remove diffusion layer porosity.4.Conclusions(1) Of AISI304 stainless steel plasma boronizing paste, the formation of boride layer of the most effective and most economical cream ratio is 30% mass fraction of amorphous boron and 70% of borax.(2) Plasma Pasty boronizing method than the traditional method of thermal diffusion boride in a shorter time and lower temperatures, has been flattened thick boride layer.(3) Plasma Pasty boride of AISI304 stainless steel micro-structure from far and near are the boride layer, the Ni-rich layer, the chromium-rich layer, matrix, etc. Boron in the process of infiltration, with low solubility of nickel boride layer formed on the surface, excessive nickel boride layer by diffusion in the formation of Ni-rich layer below. Some elements into the Cr boride layer, and some spread to the substrate, resulting in Ni-rich layer between the substrate and the formation of chromium-rich layer.(4) AISI304 stainless steel form a boride layer of the activation energy is 123 kJ per mole, which is significantly lower than the traditional method to measure the thermal diffusion of boron penetration into the data.半连不锈钢 AISI 304 的等离子膏剂渗硼处理1、概述AA3003 合金近年来， 对表面处理工艺的发展已在广泛的研究，以改善不锈钢在高温高压应用下的磨损和抗氧化性能。不锈钢可用的表面处理方法包括氮化，渗碳，等离子涂层，渗硼。特别是，渗硼是通过渗透和扩散硼到表面形成硼化物层（硬度（HV）在 1300 至 2100 之间）的表面处理方法。硼化物层也有出色的耐热性和抗腐蚀性，并且渗硼已应用于改善阀门，燃烧器，喷嘴等的表面性能，当它们在高温高压下暴露在水和油中时。然而，最近经过改良的渗硼工艺如等离子渗过程已经广泛的研究，因为传统的渗硼工艺，如正式盐浴渗硼和气体渗硼会出现如环境污染，毒性，爆炸性性质等问题。等离子渗硼拥有许多优势比传统的渗硼工艺。例如，一个高能源效率期望作为一种等离子高能量的来源被利用在等离子渗硼过程中，而且变形可以被尽量减少，因为加工温度相对低于传统工艺。然而，等离子渗硼进程也有其自身的局限。 BZH6 和BC13 气体被用来作为硼源气体，但这些气体相对昂贵，而且有毒，有爆炸性。在真空室中通过硼氯腐蚀是另一个严重的问题对等离子渗硼来说。在这项研究中，作为发展一种解决上述提到问题的渗硼工艺的多中尝试中的一种，涉及到用无定形硼和硼砂（Na 2B4O7）膏剂的一种简单处理的等离子膏剂渗硼法已经被设计，最佳的等离子膏剂渗硼工艺条件已经进行了调查，由此法形成的硼化物层已有一定特点。2、实验方法本实 AISI304 不锈钢标本（直径 15 毫米，厚度，2.5 毫米）被用于此次试验。砂纸（1200 级）抛光标本试样表面后，干净脱污后的标本被带入实验室，在 H2 氛围中对标本进行溅射清洗是首先要进行的。在 Ar：H 2（2：1）的气体环境中，用不同配比的硼和硼砂的混合物做渗硼剂的等离子渗硼处理开始了，要在1023，1073，1123，1173 和 1223 K 几个不同温度下加热长达 7 个小时。用显微扫描电镜（日立 5-2400）研究它的微观结构，在 20 千伏加速电压下做了电子探针分析。维氏硬度测定使用了 0.1 公斤力负荷，采用 7 个读数的平均值。CuK 射线衍射仪被用于 X射线衍射分析。等离子膏剂渗硼用的器具和其他试验的细节在参考文献中用描述。3、实验结果及讨论3.1 膏剂混合物的比例对硼化物层形成的影响Fig1 The effect of various ratios of amorphous boron and borax mixturethickness of the boride layer.图 1. 不同配比的无定形硼和硼砂的混合物对硼化物层厚度的影响图.1 显示了用不同比例的膏剂渗硼在 1123 K 温度下保温 1.5 小时后硼化物层的厚度。观察了用质量分数为 20%和 70%的硼砂形成的厚硼化物层。而用质量分数为 100%的无定形硼形成的任何可测量厚度的硼化物层没有被观察到，这可能归因于在等离子渗硼期间由于无定形硼的高熔点造成的用于表面扩散的活性硼的缺少。当硼砂的质量分数增加到 20%时，活跃形成的渗硼层被观察。在渗硼期间，硼原子，B 0，是通过膏剂中的硼的氢化物（BnHm）的分解产生的，而且这个硼原子 B0 变成熔融的硼砂或辉光放电里活跃的硼原子 B+1。最后，这个硼原子，B +1，扩散，和铁反应，然后形成硼化物层。用质量分数为 30%的硼和 70%的硼砂的膏剂形成的硼化物层也被观察，这可能归因于有效的液态电解机制，当随着膏剂中硼砂数量的增加，熔融硼砂的流动性增加的时候。此外，用质量分数 40 和 55%的膏剂，渗硼时比较慢速率被观察，正如图 1 所示。据推测，对包括气体，电解，液体非电解等在内各种渗硼机制来说，活跃在这个成分范围内将是困难的，由于一些原因，因此需要进一步调查研究。图 1 中不锈钢硼化物层的厚度低于温和的碳素钢，这证实了以前报告过的结果7,8。这不仅是因为在不锈钢的表面有一个防护层，而且在鉻，镍等硼化物的表面也有防护层，它们形成与晶界，从而阻止了硼的扩散7,8。也有人指出，由于硼的数量的增加，膏剂变得过量，粘着在标本的表面当等离子膏剂渗硼开始后，导致这膏剂的回收率非常低。考虑到硼元素的高成本，因此推断出等离子膏剂渗硼用的最佳膏剂成分是质量分数 30%的无定形硼和 70%的硼砂。3.2 温度和时间对渗硼层形成率的影响Fig. 2. Relation between the boroniding temperature and times on thethickness of the boride layer.图 2 渗硼温度和时间之间的关系对硼化物层深度的影响图 2 显示了渗硼温度和时间对硼化物层深度的影响。根据抛物线原理，随着渗硼时间和温度的增加，硼化物层的深度也跟着增加。这表明硼化物层的形成率变的缓慢了随着渗硼时间的增加。这可以用这样一个事实