镍基高温合金表面完整性研究现状分析

表面完整性是评价零件表面加工质量的重要标准之一。在切削镍基高温合金GH4169的过程中,加工硬化、变质层的形成等是重要的加工难题,因此研究GH4169零件的表面完整性对其高速切削加工过程有重要的意义。从表面粗糙度、表面加工硬化、白层以及表面残余应力等方面对切削镍基高温合金的表面完整性研究进展进行总结,从切削用量、工艺参数和刀具的选用等方面为提升加工零件表面质量提供了重要依据。     

Corrosion and Cavitation Erosion Behaviours of Cast Nickel Aluminium Bronze in 3.5% NaCl Solution with Different Sulphide Concentrations

The effect of sulphide(Na_2S) concentration(SC) on the corrosion and cavitation erosion behaviours of a cast nickel aluminium bronze(NAB) in 3.5% NaCl solution is investigated in this study.The results show that when the SC exceeds 50 ppm,the hydrogen evolution reaction dominates the cathodic process,and a limiting current region appears in the anodic branch of the polarisation curve due to the formation of a copper sulphide film,which is a diffusion-controlled process.After longterm immersion,the increased mass loss rate of NAB with the sulphide additions of 20 and 50 ppm is attributed to the less protective films,which contains a mixture of copper oxides and sulphides.Moreover,NAB undergoes severe localised corrosion(selective phase corrosion,SPC) at the β' phases and eutectoid microstructure α+κ_Ⅲ.By comparison,NAB undergoes general corrosion and a copper sulphide film is formed in 100 and 200 ppm sulphide solutions.Cavitation erosion greatly increases the corrosion rate of NAB in all solutions and causes a negative potential shift in 3.5% NaCl solution due to the film destruction.However,a positive potential shift occurs in the solutions with SC higher than 50 ppm due to the accelerated mass transfer of the cathodic process.The cavitation erosion mass loss rate of NAB increases with the increase of SC.The occurrence of severe SPC decreases the phase boundary cohesion and causes brittle fracture under the cavitation impact.The corrosion-enhanced erosion is the most predominant factor for the cavitation erosion damage when the SC exceeds 50 ppm.     

A quick method for evaluating the thresholds of workpiece surface damage in machining

This paper proposes a Pendulum-Based Cutting Test (PBCT) methodology which allows quick cutting tests for surface integrity evaluation along with providing cutting energies associated with particular level of workpiece surface damage, this is backed by an unified cutting energy model that links damage level of machined surface with energy partition in the cutting area. PBCT method could rapidly define the energy transferred to the workpiece that incurs particular magnitude of surface damage without using conventional machine tools and monitor the cutting process while only limited amount of materials is required. A demonstration of the proposed method is presented for Inconel718.     

金川二矿区深部开采稳定性分析和采矿设计优化研究

金川二矿区已进入深部开采。在采用下向胶结充填法的条件下，能不能实现无矿柱连续回采，对矿山的产量和效益影响极大。本文使用非线性有限元对预留间隔矿柱和不预留间隔矿柱两种方案的围岩应力、位移和塑性区分布以及采场的稳定性状态进行了系统的分析和比较，论证了二矿区深部实施无矿柱连续回采的合理性和可行性，为二矿区深部采矿设计优化提供了依据。     

金川矿区的下向胶结充填采矿法

金川矿区通过20年的生产实践,在3～5万m~2矿体上连续、大面积地使用下向胶结充填采矿法,取得了很大成绩。笔者在总结经验的基础上,对大面积开采中的矿柱留设、开采顺序、多阶段开采等问题提出了具体建议。     

利用原料1生产金属化阳极板试验研究

本文介绍了利用原料1在合金硫化炉进行金属化阳极板试验的过程。通过在合金硫化炉中进行原料1硫化、吹炼等试验过程,达到提镍降硫的目的。并在试验过程中摸索出了生产金属化阳极板的关键参数,同时对金属化阳极板中化学成分、镍直收率、钴直收率等关键指标进行了分析,为金属化阳极板的工业化生产提供了理论依据。     

Comparison of Soybean and Cottonseed Oils upon Hydrogenation with Nickel,Palladium and Platinum Catalysts

There is current interest in reducing the trans fatty acids (TFA) in hydrogenated vegetable oils because consumption of foods high in TFA has been linked to increased serum cholesterol content. In the interest of understanding the TFA levels, hydrogenation was carried out in this work on soybean oil and cottonseed oil at two pressures (2 and 5 bar) and 100 °C using commercially available Ni, Pd, and Pt catalysts. The TFA levels and the fatty acid profiles were analyzed by gas chromatography. The iodine value of interest is ~70 for all-purpose shortening and 95–110 for pourable oil applications. In all cases, higher hydrogen pressures produced lower levels of TFA. In the range of 70–95 iodine values for the hydrogenated products, the Pt catalyst gave the least TFA, followed closely by Ni, and then Pd, for both oils. For all three catalysts at 2- and 5-bar pressures and 70–95 iodine values, cottonseed oil contained noticeably less TFA than soybean oil; this is probably because cottonseed oil contains a lower total amount of olefin-containing fatty acids relative to soybean oil. Approximate kinetic modeling was also done on the hydrogenation data that provided additional confirmation of data consistency.     

Ni-WOx催化剂上正辛烷加氢异构化反应性能的研究

采用浸渍法制备Ni-WOx催化剂,在常压连续流动固定床反应器上考察了Ni-WOx催化剂上正辛烷加氢异构化的催化性能。讨论了焙烧温度、Ni的含量、还原条件和反应条件对催化剂性能的影响,对Ni-WOx催化剂进行了XRD和BET表征。实验结果表明,在Ni-WOx催化剂上,焙烧温度为800℃,还原温度为525℃,反应温度为275℃,Ni-WOx催化剂对正辛烷异构化反应的转化率达到58.17%,同时其异构化选择性达到87.33%。通过XRD表征推测催化剂的活性相主要为WO2,正辛烷在Ni-WOx催化剂上是按照传统的双功能机理进行反应的。     

La-Ni-Al合金中镍的测定

镍离子本身具有鲜艳的兰绿色,这一特性可用于镍的测定.文章结合La-Ni-Al合金中镍的测定方法研究,重点考察了本色光度法测镍的相关条件,设计了La-Ni-Al合金中镍的分析方法.方法具有高选择性、准确、简便、快速、经济的优点.     

Renewable hydrogen production from steam reforming of glycerol (SRG) over ceria-modified γ-alumina supported Ni catalyst

Excess crude glycerol derived as a by-product from biodiesel industry prompts the need to valorise glycerol to value-added chemicals. In this context, catalytic steam reforming of glycerol (SRG) was proposed as a promising and sustainable alternative for producing renewable hydrogen (H₂). Herein, the development of nickel (Ni) supported on ceria-modified mesoporous γ-alumina (γ-Al₂O₃) catalysts and their applications in catalytic SRG (at 550–750 °C, atmospheric pressure and weight hourly space velocity, WHSV, of 44,122 ml·g⁻¹·h⁻¹ (STP)) is presented. Properties of the developed catalysts were characterised using many techniques. The findings show that ceria modification improved Ni dispersion on γ-Al₂O₃ catalyst support with highly active small Ni particles, which led to a remarkable catalytic performance with the total glycerol conversion (ca. 99%), glycerol conversion into gaseous products (ca. 77%) and H₂ yield (ca. 62%). The formation rate for H₂ production (14.4 × 10⁻⁵ mol·s⁻¹·g⁻¹, TOF (H₂) = 3412 s⁻¹) was significantly improved with the Ni@12Ce-Al₂O₃ catalyst, representing nearly a 2-fold increase compared with that of the conventional Ni@Al₂O₃ catalyst. In addition, the developed catalyst also exhibited comparatively high stability (for 12 h) and coke resistance ability.