In vitro performance of a biodegradable zinc alloy adjustable-loop cortical suspension fixation for anterior cruciate ligament reconstruction

Anterior cruciate ligament(ACL)injuries of the knee are one of the most common and serious athletic injuries.The widely used cortical suspension fixation buttons for ligament reconstruction are permanent implants,particularly those made from conventional steel or titanium alloys.In this study,a biodegradable Zn-0.45Mn-0.2Mg(ZMM42)alloy with the yield strength of 300.4 MPa and tensile strength of 329.8 MPa was prepared through hot extrusion.The use of zinc alloys in the preparation of cortical suspension fixation buttons was proposed for the first time.After 35 d of immersion in simulated body fluids,the ZMM42 alloy fixation buttons were degraded at a rate of 44μm/a,and the fixation strength was retained(379.55 N)in the traction loops.Simultaneously,the ZMM42 alloy fixation buttons exhibited an increase in MC3T3-E1 cell viability and high antibacterial activity against Escherichia coli and Staphylococcus aureus.These results reveal the potential of biodegradable zinc alloys for use as ligament reconstruction materials and for developing diverse zinc alloy cortical suspension fixation devices.

Simultaneous extraction of gold and zinc from refractory carbonaceous gold ore by chlorination roasting process

A novel process based on chlorination roasting was proposed to simultaneously recover gold and zinc from refractory carbonaceous gold ore by using NaCl as chlorination agent.The effects of roasting temperature,roasting time and NaCl content on the volatilization rates of gold and zinc were investigated.The reaction mechanism and the phase transition process were also analyzed by means of SEM,EDS and XRD.The results demonstrated that under the optimal conditions of NaCl content of 10%,roasting temperature of 800℃,roasting time of 4 h and gas flow rate of 1 L/min,the rates of gold and zinc were 92%and 92.56%,respectively.During low-temperature chlorination roasting stage,a certain content of sulfur was beneficial to the chlorination reactions of gold and zinc;and during high-temperature chlorination roasting stage,the crystal structure of vanadium-bearing mica was destroyed,and the vanadium-containing oxides were beneficial to the chlorinating volatilization of gold and zinc.Eventually,the chlorinated volatiles of gold and zinc could be recovered by alkaline solution.

Support effect of zinc tin oxide on gold catalyst for CO oxidation reaction

Nanostructured gold catalyst supported on metal oxide is highly active for the CO oxidation reac‐tion. In this work, a new type of oxide support, zinc tin oxide, has been used to deposit 0.7 wt%Au via a deposition‐precipitation method. The textural properties of Zn2SnO4 support have been tuned by varying the molar ratio between base （N2H4＆#183;H2O） and metal ion （Zn2＋） to be 4/1, 8/1 and 16/1. The catalytic tests for CO oxidation reaction revealed that the reactivity on Au‐Zn2SnO4 with N2H4＆#183;H2O/Zn2＋ = 8/1 was the highest, while the reactivity on Au‐Zn2SnO4 with N2H4＆#183;H2O/Zn2＋ =16/1 was almost identical to that of the pure support. Both fresh and used catalysts have been characterized by multiple techniques including nitrogen adsorption‐desorption, X‐ray diffraction, transmission electron microscopy, high‐angle annular dark‐field scanning transmission electron microscopy, X‐ray photoelectron spectroscopy, X‐ray adsorption fine structure, and tempera‐ture‐programmed reduction by hydrogen. These demonstrated that the textural properties, espe‐cially pore volume and pore size distribution, of Zn2SnO4 play crucial roles in the averaged size of gold nanoparticles, and thus determine the catalytic activity of Au‐Zn2SnO4 for CO oxidation.

Novel zinc alloys for biodegradable surgical staples

BACKGROUND The development of biodegradable surgical staples is desirable as non-biodegradable Ti alloy staples reside in the human body long after wound healing, which can cause allergic/foreign-body reactions, adhesion, or other adverse effects. In order to develop a biodegradable alloy suitable for the fabrication of surgical staples, we hypothesized that Zn, a known biodegradable metal, could be alloyed with various elements to improve the mechanical properties while retaining biodegradability and biocompatibility. Considering their biocompatibility, Mg, Ca, Mn, and Cu were selected as candidate alloying elements, alongside Ti, the main material of clinically available surgical staples.AIM To investigate the in vitro mechanical properties and degradation behavior and in vivo safety and feasibility of biodegradable Zn alloy staples.METHODS Tensile and bending tests were conducted to evaluate the mechanical properties of binary Zn alloys with 0.1–6 wt.% Mg, Ca, Mn, Cu, or Ti. Based on the results,three promising Zn alloy compositions were devised for staple applications(wt.%): Zn-1.0Cu-0.2Mn-0.1Ti(Zn alloy 1), Zn-1.0Mn-0.1Ti(Zn alloy 2), and Zn-1.0Cu-0.1Ti(Zn alloy 3). Immersion tests were performed at 37℃ for 4 wk using fed-state simulated intestinal fluid(Fe SSIF) and Hank’s balanced salt solution(HBSS). The corrosion rate was estimated from the weight loss of staples during immersion. Nine rabbits were subjected to gastric resection using each Zn alloy staple, and a clinically available Ti staple was used for another group of nine rabbits. Three in each group were sacrificed at 1, 4, and 12 wk post-operation.RESULTS Additions of ≤1 wt.% Mn or Cu and 0.1 wt.% Ti improved the yield strength without excessive deterioration of elongation or bendability. Immersion tests revealed no gas evolution or staple fracture in any of the Zn alloy staples. The corrosion rates of Zn alloy staples 1, 2, and 3 were 0.02 mm/year in HBSS and 0.12, 0.11, and 0.13 mm/year, respectively, in Fe SSIF. These degradation times are sufficient for wound healing. The degradation rate is notably increased under low pH conditions. Scanning electron microscopy and energy dispersive spectrometry surface analyses of the staples after immersion indicated that the component elements eluted as ions in Fe SSIF, whereas corrosion products were produced in HBSS, inhibiting Zn dissolution. In the animal study, none of the Zn alloy staples caused technical failure, and all rabbits survived without complications. Histopathological analysis revealed no severe inflammatory reaction around the Zn alloy staples.CONCLUSION Staples made of Zn-1.0Cu-0.2Mn-0.1Ti, Zn-1.0Mn-0.1Ti, and Zn-1.0Cu-0.1Ti exhibit acceptable in vitro mechanical properties, proper degradation behavior,and in vivo safety and feasibility. They are promising candidates for biodegradable staples.

Strength properties examination of high zinc aluminium alloys inoculated with Ti addition

This paper includes studies on the influence of grain refinement treatment with respect to the composition and structure of high zinc aluminium casting alloys on the changes of their tensile properties. The Al-20 wt.%Zn alloy was inoculated with master alloys Al Ti5B1 and Al Ti3C0.15 to determine the impact of a variable titanium addition on the tensile properties of Al Zn20 alloy, and determine on this basis an optimal addition of Ti that would ensure the improvement of elongation of alloys cast in the sand mould, at the same time maintaining high tensile strength. Within the studies, light microscopy(LM) and strength tests were applied. Experimental results showed that the inoculation of high zinc aluminium alloy Al Zn20 with the master alloys Al Ti5B1 and Al Ti3C0.15 causes intensive structure refinement, while the intensity of reaction of both master alloys is comparable. The Al Ti3C0.15 master alloy addition, selected for further studies, introducing about 100 ppm Ti, enhances the tensile properties of the alloy; the elongation increases about 20% and tensile strength increases about 10% against the initial values(uninoculated alloy). Further increase of the Ti addition up to 500–600 ppm leads to the "overinoculation" effect that is accompanied by the decrease of elongation. Therefore,the Ti addition should be reduced to the level of about 100 ppm which ensures obtaining a set of optimal properties.

Slurry wear characteristics of zinc-based alloys： Effects of sand content of slurry, silicon addition to alloy system and traversal distance

这调查处理在泥浆上与标本和泥浆作文以及遍历距离的效果相关的观察穿基于锌的合金的反应。合金的作文被把 4% 硅加到它改变。泥浆作文通过在被推迟在的 060% 的范围改变沙粒子的集中被改变(液体) 电解质。电解质包含了集中的硫的酸在水的 10 L 溶解了的 4 g 钠氯化物和 5 mL。泥浆穿测试在 15500 km 的遍历距离范围上以 7.02 m/s 的速度被进行。wear 率开始与遍历距离增加了，达到了最大值并且不管标本和测试环境，此后减少了。然而， wear 率山峰比液体唯一的媒介在加沙环境的液体是不太突出的。进一步，在液体唯一的媒介的 wear 率山峰在包含泥浆的沙比那座出现在更短的遍历距离。到电解质的沙粒子的增加把样品的 wear 率归结为取决于泥浆的沙集中的 5%15% 。而且，中介(40%) 沙内容导致了最大值穿率什么时候与相比在加沙媒介的液体。然而，这最大值是静止的不到在里面液体唯一的媒介。包含更高受不了的合金的硅比当在液体唯一的媒介测试了时，免费合金取样的硅穿率。相反，而混合回答在包含 60% 沙的泥浆被注意，趋势加 20% 和 40% 沙环境在液体逆行。在后者盒子中，当一个相反的趋势在更长的遍历距离被观察时，硅的存在开始证明有害。样品的 wear 反应在试验性的条件的一个给定的集合以他们象硅和占优势的材料移动机制一样的 microconstituents 的特定的特征被讨论。合金的观察行为也通过他们的影响表面和表面下的区域的特征进一步被证实。

Stable anode-free zinc-ion batteries enabled by alloy network-modulated zinc deposition interface

Newly-proposed anode-free zinc-ion batteries(ZIBs)are promising to remarkably enhance the energy density of ZIBs,but are restricted by the unfavorable zinc deposition interface that causes poor cycling stability.Herein,we report a Cu-Zn alloy network-modulated zinc deposition interface to achieve stable anode-free ZIBs.The alloy network can not only stabilize the zinc deposition interface by suppressing 2D diffusion and corrosion reactions but also enhance zinc plating/stripping kinetics by accelerating zinc desolvation and nucleation processes.Consequently,the alloy network-modulated zinc deposition interface realizes high coulombic efficiency of 99.2%and high stability.As proof,Zn//Zn symmetric cells with the alloy network-modulated zinc deposition interface present long operation lifetimes of 1900 h at 1 m A/cm^(2)and 1200 h at 5 m A/cm^(2),significantly superior to Zn//Zn symmetric cells with unmodified zinc deposition interface(whose operation lifetime is shorter than 50 h),and meanwhile,Zn3V3O8cathodebased ZIBs with the alloy network-modified zinc anodes show notably enhanced rate capability and cycling performance than ZIBs with bare zinc anodes.As expected,the alloy network-modulated zinc deposition interface enables anode-free ZIBs with Zn3V3O8cathodes to deliver superior cycling stability,better than most currently-reported anode-free ZIBs.This work provides new thinking in constructing high-performance anode-free ZIBs and promotes the development of ZIBs.

Effect of magnesium on the aluminothermic reduction rate of zinc oxide obtained from spent alkaline battery anodes for the preparation of Al–Zn–Mg alloys

The aluminothermic reduction of zinc oxide（ZnO） from alkaline battery anodes using molten Al may be a good option for the elaboration of secondary 7000-series alloys. This process is affected by the initial content of Mg within molten Al, which decreases the surface tension of the molten metal and conversely increases the wettability of ZnO particles. The effect of initial Mg concentration on the aluminothermic reduction rate of ZnO was analyzed at the following values： 0.90wt%, 1.20wt%, 4.00t%, 4.25wt%, and 4.40wt%. The ZnO particles were incorporated by mechanical agitation using a graphite paddle inside a bath of molten Al maintained at a constant temperature of 1123 K and at a constant agitation speed of 250 r/min, the treatment time was 240 min and the ZnO particle size was 450？500 mesh. The results show an increase in Zn concentration in the prepared alloys up to 5.43wt% for the highest initial concentration of Mg. The reaction products obtained were characterized by scanning electron microscopy and X-ray diffraction, and the efficiency of the reaction was measured on the basis of the different concentrations of Mg studied.

Microchemical Characterization of Natural Gold and Copper Alloys from the Ancient Um Shashoba Gold Mine, South Egypt

The SEM-EDX technique was applied to investigate Au, and Cu＋Sn alloyed grains in the mineralization of the Um Shashoba mine for achieving further understanding of occurrences, internal structures and microchemistry of Au and Cu alloys and associated minerals, and mineralization type. This study is aiming at the genetic history of ore-bearing fluid events, geochemical evaluation and exploration significance. The results showed that the mineralization could be considered as a single major episode generated by metamorphic mesothermal solution rich in sulfides and unsaturated respect to Au. It was differentiated into many stages; started with formation of auriferous pyrite that was pseudomorphed by secondary hematite, limonite and goethite. Three phases of Au alloy were precipitated, and Cu＋Sn and Ag-rich alloys were produced respectively and followed by deposition of two generations of barren pyrite. Calcite and ankerite were crystalized, surrounded and partially replaced some of early formed minerals. Finally, barren muscovite recrystallized around and inside both later formed carbonate minerals that were free of any sign of Au in their structures. The processes of deformation, recrystallization, annealing, dissolution, remobilization and re-precipitation played the most important roles in the genetic history of the mineralization.

Influence of Gadolinium with Small Content on Recrystallization Behaviour in Silver-Gold Alloys

The influence of small addition of RE element Gd on recrystallization behaviour in isomorphous Ag-Au alloys was studied by differential scanning calorimetry, optical microscopy, transmission electron microscopy and hardness measurement. It is shown that in alloys with 0.2% Gd, disperse second-phase particles are formed, which results in obvious increase in the recrystallization temperature and grain refining. The recrystallization temperature of AgAuGd0.2 alloys also increases with cold working. Small addition of Gd raises the apparent activation energy of recrystallization for Ag-Au alloys.

Effect of heat diffusion on properties of zinc-aluminum coating on AZ91D magnesium alloys

A protecting zinc and aluminum coating on the surface of AZ91D magnesium alloys was obtained by thermal spraying to improve the corrosion and wear resistance performances. In order to enhance the combination between magnesium alloy matrix and zinc and aluminum coating, the sample was heat-treated at 300℃for 2 h, then, the cross-section patterns, XRD pattern, micro-hardness, wear and corrosion resistance abilities were researched. The results indicate that the interface between the coating and substrate is metallurgical bond, and a transitional fusion layer is formed by diffusion. The micro-scale abrasion test and polarization test in 3% NaCl solution show that the diffusion-treated specimen has better wear and corrosion resistance performances in comparison with the undiffusion-treated and substrate magnesium alloys; in addition, it has relatively higher micro-hardness than the undiffusion-treated magnesium alloys.

Electroplating zinc transition layer for electroless nickel plating on AM60 magnesium alloys

Electroplating zinc coating as transition layer of electroless nickel plating on AM60 magnesium alloys was investigated. The zinc film can be deposited in a pyrophosphate bath at 50-60℃under current density of 0.5-1.5 A/dm2. A new fore treatment technology was applied by acid cleaning with a solution containing molybdate and phosphorous acid, by alkaline cleaning in a bath containing molybdate and sodium hydroxide. The subsequent electroless plating was carried out in nickel sulfate bath. The SEM observation shows that the deposition is uniform and compact. The polarization curve measurements show that the corrosion potential of the zinc plating in 3.5% NaCl is about -1.3 V(vs SCE) which is noble than that of magnesium substrate. The zinc electroplating can be applied as the pretreatment process for electroless nickel plating on magnesium alloys.

Effectiveness Evaluation Study of Self-made Zinc Alloy Sacrificial Anode under Chloride Salt Erosion Environment

To investigate the effectiveness of self-made zinc alloy sacrificial anode material for the protection of reinforcement in concrete under chlorine salt erosion environment,salt solution immersion corrosion and electromigration accelerated corrosion tests were used to evaluate the effectiveness of self-made zinc alloy anode with the help of relevant cathodic protection guidelines and evaluation criteria for the corrosion of reinforcement in concrete.The results showed that the protection was effective because the potential of the zinc alloy anode protection steel bar in the salt solution satis?ed the“-780 mV(SCE)”validity criterion.The self-corrosion potential(E_(corr))of the sacri?cial anode protection steel in concrete was greater than-276 mV,and the protective current density of the zinc alloy anode was 1-3μA·cm^(-2),which met the standards of EN12696-2000,further indicating that the self-made zinc alloy sacri?cial anode had a good protection combining with the polarization resistance and the appearance of the corroded surface of the steel in concrete.The microscopic morphology of the corroded surface and the composition of the corrosion products indicates that the mortar of the self-made zinc alloy anode has a lower pH than the imported anodes,so the long-term protection of the selfmade zinc alloy sacri?cial anode needs to be further improved.

METALLOGENIC ANALYSIS OF THE DEXING COPPER-GOLD-LEAD-ZINC POLYMETALLIC DEPOSITS, JIANGXI PROVINCE, CHINA

The paper discusses the tectonic setting of the fortnation of the Dexing giant copper-gold-lead-zinc deposit and its geological features and demonstrates in detail the polygenetic compound mechanism of its formation.

废电解液在湿法炼锌渣中回收金、银、锌的应用研究

锌电解过程产出大量的废电解液,废电解液酸性较强并含有多种金属离子,如直接排放会对环境造成严重污染。以废电解液和浓硫酸作为浸出介质,研究了采用酸浸—浮选工艺综合回收湿法炼锌渣中金、银、锌。以常规浸出工艺产生的浸出渣(老渣)为主要研究对象,考察了矿浆搅拌速度、废电解液用量、硫酸补加量、酸浸温度对金、银浮选指标的影响。结果表明:酸浸—浮选老渣闭路试验最终获得的精矿中金品位为10.16 g/t,金回收率为78.63%,银品位为1039.64 g/t,银回收率为74.72%,锌品位为40.64%,锌回收率为21.86%,酸浸液中锌回收率为60.15%;采用热酸浸出工艺产生的浸出渣(新渣)和现浸出过程产出的新鲜渣浆进行验证试验可获得较好的闭路试验指标。该方法可实现废电解液的循环利用,使渣中有价金属得到高效综合回收。

不同镀层板的电阻点焊腐蚀行为

[目的]研究点焊对不同镀层板腐蚀行为的影响。[方法]对镀锌板和镀锌铝镁板进行电阻点焊,采用扫描电镜和能谱仪分析了点焊部位的微观形貌和元素分布。通过中性盐雾试验和电化学阻抗谱测试研究了两种板材点焊前后在相同环境下的腐蚀行为。[结果]点焊镀锌板的焊点边缘存在大量凸起和凹坑,而点焊镀锌铝镁板的焊点边缘无明显的凸起和凹坑。二者的焊点位置Zn元素挥发明显,均有部分基体裸露。无论点焊与否,镀锌板在中性盐雾试验中的耐腐蚀能力都不如镀锌铝镁板。[结论]电阻点焊容易导致镀层局部破损,影响镀层的耐蚀性。

X射线荧光光谱法测定锌合金中铜和铝的含量

建立了一种通过X射线荧光光谱法测定锌合金中铜、铝含量的方法,并利用整套锌合金标准样品建立了标准曲线,优化了仪器条件,采用经验系数法对基体效应进行了校正。对参与曲线建立的标准品进行测定,测定值的相对标准偏差为铜0.4%、铝0.04%;对未参与曲线建立的标准品进行7次测定,测定结果的平均值与认定值的差值绝对值铝为0%、铜为0.03%,均小于现行国家标准方法的重复性限。

氯化钾滚镀锌关键技术的开发研究

在氯化钾滚镀锌槽中间加隔板将其分成两个滚镀锌槽。第一镀槽中的亚铁杂质视作镀液的有效成分,将镀锌改为镀锌铁合金。第二镀槽切断了亚铁杂质的主要来源,用于制备高质量的镀锌层。钢铁件在第一镀槽中镀锌铁合金制备底镀层,然后在第二镀槽中镀锌得到面镀层,从而消除了铁杂质对氯化钾镀锌的不良影响,克服了传统工艺镀层出现滚桶眼子印和钝化困难等技术缺陷。本工艺无需处理氯化钾镀锌槽中的铁杂质,解决了用双氧水氧化处理法导致镀液性能下降的问题。结果表明:所制备的镀锌铁合金与镀锌组合镀层的耐蚀性高于传统的镀锌层。本工艺镀液维护简单,镀液和镀层性能优于传统工艺,具有良好的应用前景。

不同熔附金属对前牙烤瓷熔附金属全冠修复疗效

目的对比研究镍铬合金与金沉积对前牙烤瓷熔附金属(porcelain-fused-to-metal crown,PFM)全冠修复患者的应用效果以及对龈沟液(gingival crevicular fluid,GCF)炎症因子的影响。方法选入2020年9月-2022年2月在本院接受前牙PFM全冠修复的患者86例(86颗牙),根据修复材料不同分为镍铬合金组和金沉积组,每组43例(43颗牙)。比较两组的治疗效果、GCF炎症因子水平等指标。结果金沉积组修复体颜色、边缘密合度、边缘着色及继发龋均显著优于镍铬合金组(P<0.05),在修复体折裂瓷崩方面,两组无明显差异(P>0.05);修复6个月后,金沉积组GI、PD、GCF和GCF中TNF-α、IL-6、IL-1β和MMP-2水平水平均显著低于镍铬合金组(P<0.05);金沉积组满意度显著高于镍铬合金组(93.02%vs.74.42%,P<0.05)。结论镍铬合金与金沉积均是前牙PFM全冠修复的常用材料,而后者对患者局部牙周组织影响较小,在减轻GCF炎性因子水平、提高修复美观度及患者满意度方面优于前者。

Corrosion resistance of cerium-doped zinc calcium phosphate chemical conversion coatings on AZ31 magnesium alloy

Zinc calcium phosphate （Zn-Ca-P） coating and cerium-doped zinc calcium phosphate （Zn-Ca-Ce-P） coating were prepared on AZ31 magnesium alloy. The chemical compositions, morphologies and corrosion resistance of coatings were investigated through energy-dispersive X-ray spectroscopy （EDS）, X-ray photoelectron spectroscopy （XPS）, X-ray diffraction （XRD）, electron probe micro-analysis （EPMA） and scanning electron microscopy （SEM） together with hydrogen volumetric and electrochemical tests. The results indicate that both coatings predominately contain crystalline hopeite （Zn3（PO4）2·4H2O）, Mg3（PO4）2 and Ca3（PO4）2, and traces of non-crystalline MgF2 and CaF2. The Zn-Ca-Ce-P coating is more compact than the Zn-Ca-P coating due to the formation of CePO4, and displays better corrosion resistance than the Zn-Ca-P coating. Both coatings protect the AZ31 Mg substrate only during an initial immersion period. The micro-galvanic corrosion between the coatings and their substrates leads to an increase of hydrogen evolution rate （HER） with extending the immersion time. The addition of Ce promotes the homogenous distribution of Ca and formation of hopeite. The Zn-Ca-Ce-P coating has the potential for the primer coating on magnesium alloys.