Effects of SO2 and SO3 on the Na2SO4 induced corrosion of nickel

The effects of SO₂ and SO₃ in the environment on the hot corrosion behavior of Ni in the temperature range 750–950°C has been studied. Below the melting point of Na₂SO₄ (884°C), rapid corrosion takes place by formation of a Na₂SO₄-NiSO₄ melt, which can penetrate the porous oxide scale and give rise to sulfide information by coming in contact with the metal. The distribution of the sulfides depends on the SO₂ level in the ambient gas. Continued corrosion occurs by a sulfidation-oxidation mechanism. At temperatures above the melting point of Na₂SO₄, accelerated degradation occurs via dissolution of the surface scale, followed by reprecipitation of the oxide in a nonprotective form.Deceased     

Electroless Ni-B deposition from an emulsified supercritical carbon dioxide bath

The electroless deposition of boron-containing Ni (EN-B) film from a supercritical carbon dioxide (sc-CO₂) bath was introduced. The deposition rate in sc-CO₂ bath was one order of magnitude lower than that at ambient pressure without the presence of sc-CO₂. A more uniform chemical composition of the EN-B film could be obtained if it was deposited in the sc-CO₂ bath. X-ray diffraction analyses revealed that the as-deposited film was amorphous in nature, despite of the deposition condition. Deposition defects such as cracks and voids could be avoided if the deposition was conducted in the sc-CO₂ bath. Crystallization and boride precipitation were found after heat treatment at 400 °C for 1 h. The EN-B film deposited from the sc-CO₂ bath had a higher hardness as compared with that of the normal EN-B coating. A substantial increase in hardness was obtained due to boride precipitation.     

Mg-8Zn-4Al合金的化学镀镍

对Mg-8Zn-4Al合金上直接进行化学镀镍进行了研究，运用X射线粉末衍射仪、扫描电镜、金相显微镜和M532腐蚀电化学测量系统等分析了Mg-8Zn-4Al合金的组织特点和镀层的表面形貌及性能特征．结果表明：基体为α(Mg)，白色相为ψ(Al2Mg5Zn2)和τ(Mg32(Al，Zn)49)三元相，黑灰色相为共晶α(Mg)．镀层厚度约为30μm，镀镍前后的Econ由-1．55V升高到-0．4V，表明镀层平整、致密，与基体结合牢固，可有效保护Mg-8Zn-4Al合金。     

涤纶织物化学镀镍的研究

采用化学镀镍技术对涤纶织物进行了酸性、碱性镀镍以及着色处理。借助SEM、X射线能谱仪对化学镀镍织物表面结构进行了表征和分析。测试了涤纶织物化学镀镍前后服用性能的变化,并对导电性和电磁波屏蔽性能进行了测试。结果表明,镀层均匀程度对电磁波屏蔽性能影响较大。随着镀镍层厚度的增加,电磁波屏蔽效能增速先增大后减小。酸性镀镍织物的电磁波屏蔽性能优于碱性镀镍织物。镀层织物经着铜色处理后,电磁波屏蔽性能有明显提高。当质量增加70％时,化学镀涤纶织物电磁屏蔽性能较好,同时服用性能变化不明显。     

镍及其制品贸易格局演变及中国贸易网络分析

镍在不锈钢行业中有着稳定的需求,含镍电池也引发了镍需求的进一步增长.本文基于2010—2019年数据构建全球镍及其制品贸易网络,从贸易价值、网络结构和网络影响力对全球贸易格局进行分析,对贸易价值和经济发展指标进行相关性分析,从贸易伙伴和贸易集中度对中国贸易网络特征进行分析.研究发现:镍及其制品贸易价值受经济发展影响,发...     

Removal of Heavy Metal Ions from Aqueous Solutions Using Lignocellulosic Fibers

Abstract

Spruce, coconut coir, sugarcane bagasse, kenaf bast, kenaf core, and cotton were tested for their ability to remove copper, nickel and zinc ions from aqueous solutions as a function of their lignin content. The fibers were analyzed for sugar and lignin content and extracted with di-ethyl ether, ethyl alcohol, hot water, or 1% sodium hydroxide.

The order of lignin content in un-extracted fibers is coconut coir > spruce > kenaf core > bagasse > kenaf bast > cotton. The fiber with the highest level of heavy metal removal was kenaf bast that had a very low level of lignin, showing that removal of heavy metals does not correlate with lignin content. Cotton, with about 1% lignin, was very low in metal ion sorption while all of the fibers containing lignin did remove heavy metal ions showing that lignin does play a role in metal ion sorption. Extraction with the various solvents removed different cell wall components and did change heavy metal sorption that indicates that cell wall chemistry and architecture may also be important factors in the sorption of heavy metals from aqueous solutions using lignocellulosic fibers.     

纳米镍的制备及氢化大豆油的分析

以液相还原法制备纳米镍催化剂,并通过X-射线衍射、扫描电子显微镜、粒径分析及N2吸附脱附等手段对催化剂进行表征。结果表明：纳米镍催化剂比表面积为42.35?m2/g,平均粒径为30.0?nm,孔容为0.029?cm3/g,表面附着表面活性剂使其成球性和分散性较好,有利于催化剂活性的提高。纳米镍氢化一级大豆油的活性是雷尼镍的2.01?倍,当氢化油脂碘值约为90?g?I/100?g时,纳米镍催化剂的亚油酸选择性为0.51,反式脂肪酸异构化的选择性为0.35,氢化油脂的反式脂肪酸相对含量较雷尼镍的低10.79%。     

基因工程菌Escherichia coli BL21/pET-pel重组果胶酶的纯化及酶学性质

采用超声波破碎法、镍离子亲合层析柱法,纯化重组菌Escherichia coli BL21/pET-pel表达的胞内重组果胶酶,并用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（sodium dodecyl sulfate-polyacrylamide pelelectrophoresis,SDSPAGE）检测,研究纯化的重组果胶酶酶学性质。结果表明：重组果胶酶纯化倍数为1.71,回收率为88.5%,分子质量约为44 kD。最适pH值为9.0～9.5,在pH 7.0～10.0之间催化性质较稳定;最适作用温度范围为45～55 ℃,在60 ℃下保温30 min还剩余40%的酶活力;在离子浓度为1 mmol/L时,Ca2+和Co2+对该酶有较强的促进作用,而Fe2+则对其有较强的抑制作用。     

镍闪速熔炼新渣型的物化性质研究

金川镍铜渣中铁的还原性差、难以作为炼铁炉料直接入炉冶炼。提出了提高渣中CaO含量、降低SiO2含量为后续提铁创造条件的工艺设想,并利用FactSage计算模拟软件对金川镍闪速熔炼渣主要成分的相图进行模拟计算,通过试验考察了不同炉渣组分对熔渣物化性质影响的规律。结果表明,合适的新渣型为Fe/SiO2=1.5,CaO 10%～15%,MgO 9%。     

凝胶-溶胶法制备单分散菱柱形草酸镍的研究

以Ni(OH)2凝胶为前驱体.采用凝胶-溶胶法制备了单分散菱柱形二水草酸镍.采用SEM,XRD 等方法及Imagetool图像分析软件,对所制备的NiC2O4·2H2O粉末形貌及形成机理等进行了研究,结果表明,控制适当条件,可使NiC2O4·2H2O颗粒在低过饱和度下均匀生长,其形成机理为溶解-再结晶;随温度升高,粉末...