力学性能可调的高氧钛原位电弧增材制造

通过电弧增材制造原位制备高氧钛,并对高氧钛的成分偏析、显微组织和力学性能进行研究。结果表明,高氧钛试样的显微组织主要呈现为针状α相集束。随着氧含量的增加,试样针状α相逐渐变宽,集束尺寸变大。受氧的强化作用以及晶粒尺寸效应共同影响,试样的强度先提高后下降,伸长率显著下降,断裂形式由塑性断裂向解理断裂过渡。当氧含量达到0.37%(质量分数)时,伸长率约为7%,试样抗拉强度超过730 MPa,约为商业纯钛的2倍。

TO-3催化剂对合成气中高含量氧的脱除

在体积组成为CO 50%,H_240%和N_2+O_210%的模拟合成气中,测试了TO-3脱氧催化剂在不同反应温度、空速、压力及进口氧含量条件下脱除氧杂质的性能,结果表明该催化剂脱氧性能优异,脱除高含量氧时,出口残氧量低,在反应压力2MPa、空速6000h^(-1),温度大于180℃时可将入口体积分数为1.2%和0.9%的氧分别脱除至低于1×10^(-6)和0.2×10^(-6)。

惰气熔融-红外吸收法测定药芯焊丝药粉中高含量氧

研究了惰气熔融-红外吸收法测定药芯焊丝药粉中高含量氧的可行性,确立了氧氮氢分析仪的最佳工作条件。结果表明:在分析功率为5.5kW,称样量为20~60mg,加入0.3~0.5g纯铁做助熔剂的条件下,以重铬酸钾校准仪器,选用手动投样-间歇加热模式,可以得到满意的分析结果。方法应用于药芯焊丝药粉实际样品中氧的测定,结果与差减法测得值基本一致,相对标准偏差(n=5~7)小于5.5%,加标回收率为90%~103%。

惰气熔融-红外吸收法测定药芯焊丝药粉中高含量氧的不确定度评定

对惰气熔融-红外吸收法/手动投样方式测定药芯焊丝药粉中高含量氧的测量重复性、标准物质、天平称量等主要不确定度分量来源进行了分析与评定,计算了测量结果的合成不确定度和扩展不确定度。各不确定度分量中重铬酸钾标准物质的测量重复性和天平称量对合成不确定度的贡献较大。

合成氨系统停车后开车时氧含量高的原因分析及其预防对策

介绍了合成氨系统短期停车检修后（10h以内）开车时煤气系统存在的氧含量高的问题，并从循环洗涤水的解吸氧，气化炉开车时下吹煤气管道内的填充空气，清理洗气箱过程带入的空气，煤气总管温度降低后形成负压而吸入的空气等四个方面进行了原因分析、计算和论证。提出了解决合成氨系统停车后开车时氧含量高的措施，并在实际生产中得到了充分的证明，解决了长期以来合成氨系统停车检修后开车过程因O2含量高而带来的困扰。

ASG除氧装置制水氧含量异常的原因分析及处理

文章简要介绍了秦山第二核电厂ASG系统除氧装置的作用及流程,通过对除氧装置启动期间运行参数的分析,得出造成氧含量高的根本原因,并通过正压法和负压法计算分析得出消除水封的可行性方式以及所需的排水量,有针对性地制定了解决方案和运行建议,较好地解决了除氧装置氧含量高的问题,为相同类型的机组运行提供了参考。

高氧增材制造IN718镍基高温合金的蠕变性能

氧作为高温合金冶炼过程中难以去除的杂质元素,氧质量分数仅仅为0.0001%~0.0010%就会显著降低高温合金的疲劳与蠕变性能。增材制造技术由于其在难切削合金与复杂构件上的制造优势,已被广泛应用于高温合金的制造。然而,由于粉末的比表面积大,增材制造高温合金的氧质量分数为传统铸造的10~100倍,致使其疲劳与蠕变性能大幅下降。基于此,充分利用了选区激光熔化工艺的特点,开展了高氧含量气氛中IN718合金的打印。采用了打印室氧质量分数分别为0.001%与0.100%的环境,制备了高、低2种氧含量合金。650℃/550 MPa的蠕变与650℃/690 MPa的持久测试显示,高氧含量制造的合金的蠕变与持久寿命为低氧含量制造的合金的2倍,同时具有更好的塑性。结合光镜、扫描电镜与能谱仪,对2种合金的显微组织进行表征。结果显示,氧含量增高并未引起打印过程的烧损,且高氧含量与低氧含量制造的合金具有相同的致密度与显微组织特征,2种合金均显示出良好的冶金结合,没有明显的打印缺陷。在热处理之后,2种合金均发生了晶粒回复与再结晶,在晶界处析出了几乎同样尺寸和含量的碳化物与δ相。通过透射电镜发现高氧含量合金中具有弥散分布的Al2O3颗粒,尺寸为15~30 nm,且其附近遍布位错网。这些纳米氧化物结构稳定,可以有效阻碍位错运动,从而提升了合金的蠕变性能。详细分析了该纳米氧化物在选区激光熔化过程中的形成机制。提出利用激光增材制造特性制备含纳米氧化物合金的思路,该方法可以有效避免氧对合金损害,提升合金的性能。

WMVE工艺——一种制取M_2粉末高速钢棒材的新工艺

通过对高氧含量水雾化M_2高速钢粉(W)的磁选(M)、真空松装烧结(V)及热挤压(E)的研究,提出了WMVB新工艺。用这种工艺不仅能以高氧含量的水雾化粉末生产性能与熔炼钢相当的冶金产品,而且经济可行,适用于我国当前的冶金工业。

Effects from changes in pulp nature after ultrasonic conditioning on high-sulfur coal flotation

A study of the effects of the pulp nature on desulphurization and de-ashing during high-sulfur coal flotation is described in this paper. Highlighted are the use of a solution oxygen gauge, a pH value gauge and a surface tension gauge to investigate changes in the pulp nature related to changes in the oxygen content, the pH value and the interfacial tension. The temperature be- fore and after ultrasonic conditioning was also investigated. The results showed that ultrasonic conditioning resulted in a decrease in the oxygen content and the interracial tension and an increase in the pH value and the temperature of the pulp. The perfect index of flotation and the perfect index of desulphurization of fine coal increased by 25.19% and 18.03%, respectively, after the pulp was ultrasonically conditioned. This study shows that ultrasonic conditioning can change the pulp nature and enhance the degree of desulphurization during high-sulfur coal flotation.

Influence of coal blending on mineral transformation at high temperatures

Transformation of mineral matter is important for coal utilization at high temperatures.This is especially true for blended coal.XRD and FTIR were employed together to study the transformation of mineral matter at high temperature in blended coals.It was found that the concentration of catalytic minerals, namely iron oxides, increases with an increasing ratio of Shenfu coal, which could improve coal gasification.The transformation characteristics of the minerals in blended coals are not exactly predictable from the blend ratio.This was proved by comparing the iron oxide content to the blending ratio.The results from FTIR are comparable with those from XRD.FTIR is an effective method for examining variation in mineral matter.

多功能净化剂在煤气净化过程中的应用

本文通过对变压吸附提CO产品气中CO2超标的问题进行原因分析,通过实际整改措施对问题进行整改,并取得了良好效果。

Fabricating high-loading Fe-N4 single-atom catalysts for oxygen reduction reaction by carbon-assisted pyrolysis of metal complexes

Iron-based single-atom catalysts with nitrogen-doped carbon as support(Fe-SA/NPC)are considered effective alternatives to replace Pt-group metals for scalable application in fuel cells.However,synthesizing high-loading Fe-SA catalysts by a simple procedure remains challenging.Herein,we report a high-loading(7.5 wt%)Fe-SA/NPC catalyst prepared by carbon-assisted pyrolysis of metal complexes.Both the nitrogen-doped porous carbon(NPC)support with high specific surface area and ο-phenylenediamine(o-PD)play key roles role in the preparation of high-loading Fe-SA/NPC catalysts.The results of X-ray photoelectron spectroscopy,high-angle annular dark-field scanning transmission electron microscopy,and X-ray absorption fine structure spectroscopy experiments show that the Fe atoms are anchored on the carbon carriers in a single-atom site configuration and coordinated with four of the doped nitrogen atoms of the carbon substrates(Fe-N_(4)).The activities of the Fe-SA/NPC catalysts in the oxygen reduction reaction increased with increasing iron loading.The optimized 250Fe-SA/NPC-800 catalyst exhibited an onset potential 0.97 V of and a half-wave potential of 0.85 V.Our study provides a simple approach for the large-scale synthesis of high-loading single-atom catalysts.

Oxidation behaviors of Ni-Cr-Al superalloy foams at 1 000 °C in air

The oxidation behaviors of Ni-16Cr-xAl （x=4.5%, 9.0%, mass fraction） superalloy foams in air at 1000℃ were investigated. The effects of AI content on the resistance to high temperature oxidation were examined. The oxidation mechanisms of the foams were discussed. The results show that the resistance to the oxidation of the Ni-16Cr-xA1 based alloy at 1 000 ℃ increases with the content of A1 increasing from 4.5% to 9.0%. Complex oxide products are formed on the surface of the superalloy foams after the oxidation. Cr203 and A1203 are the predominant oxides for the scales of the foams with 4.5% A1 and 9% A1, respectively. Excellent high temperature oxidation resistance and superior pore conformation stability for the Ni-16Cr-xA1 based superalloy foam with 9% A1 can be mainly attributed to the formation of relatively continuous and protective A1203 oxides on the surface of the foam.

十二烷基硫酸钠辅助制备高电容性能多孔碳

本工作通过一步水浴法制备高氮/氧含量密胺树脂(MF),引入阴离子型表面活性剂十二烷基硫酸钠(SDS)改变聚合物的反应历程,使进入SDS胶束中的三聚氰胺与甲醛在盐酸催化条件下进行聚合反应,高温碳化后成功制备MF衍生多孔碳材料.对MF衍生多孔碳材料分别进行了扫描电镜、比表面积等表征,结果表明,其具有多孔互穿网络结构,比表面积高达387.86 m2•g^(−1),且孔径分布适宜(3.62 nm).作为超级电容器(SCs)电极材料,在1.0 A•g^(−1)下的比电容值为349.6 F•g^(−1),20.0 A•g^(−1)时(254.6 F•g^(−1))仍能维持1.0 A•g^(−1)时73.0%的电容保持率,倍率性能优异.该样品在10.0 A•g^(−1)下循环15000次后的比电容值几乎没有衰减,循环稳定性能优越.此研究结果表明SDS可辅助提升MF衍生多孔碳材料的电容性能,发展潜力巨大.