Addition Of Germanium Research Articles

The Thermomechanical, Functional and Biocompatibility Properties of a Au–Pt–Ge Alloy for PFM Dental Restorations

A high-noble Au–Pt–Ge porcelain-fused-to-metal (PFM) dental alloy without the known adverse metallic elements and with the addition of germanium (Ge) was produced as a more cost-effective alternative to other precious alloying metals, with investigations for determining the functionality and clinical use of this alloy. The thermomechanical, biocompatibility, durability, workability and economic characteristics of the produced dental alloy were investigated. These properties were investigated with in vitro biocompatibility testing on human gingival fibroblasts (HGFs); static immersion testing for metal ion release; DSC analysis; hardness, tensile testing, density and coefficient of thermal expansion (CTE) measurements; metallographic and SEM/EDX microstructure investigations; and finally with the production of a test PFM dental bridge. The results of the thermomechanical testing showed alloy properties suitable for dental restorations and clinical use, with somewhat lower mechanical properties, making the alloy not suitable for extensive multiunit fixed restorations. The microstructure investigations showed segregations of Ge in the homogeneous alloy matrix, which reduce the alloy’s mechanical properties. The produced PFM dental bridge showed excellent workability of the alloy in a dental laboratory setting, as well as a high standard of the final dental restoration. The ion release was negligible, well below any harmful quantities, while the cell viability examination showed significantly higher viability ratings on polished alloy samples as compared to as-cast samples. The results showed that a dental substructure in direct contact with oral tissue and fluids should be highly polished. The performed investigations showed that the produced PFM dental alloy is suitable for clinical use in producing high-quality dental restorations with high biocompatibility for patients prone to metal allergies.

Investigation on the reaction of sulphur with Ag–Cu–Zn-Ge alloy: Experimental and computational study

Silver and its alloys undergo tarnishing with time, which is a black stain on the surface due to the formation of Ag2S. Developing a tarnish resistant Ag alloy was attempted by alloying Ag with elements that form a passive oxide layer on the surface. Germanium is proven to provide better tarnish resistance to sterling Silver alloy (92.5 wt% pure) which is available under the trade name of Argentium©. The present work investigates the tarnish resistance behavior of sterling silver alloy (92.5 wt% pure) containing various additions of Copper, Zinc, and Germanium. The alloys were prepared by melting and casting route, followed by Passivation Heat Treatment (PHT) to create a stable and continuous oxide layer. The temperature for PHT was optimized using thermogravimetry analysis (TGA) of the alloys prepared. Accelerated tarnish test was carried out to investigate the tarnishing behavior of alloy samples obtained before and after PHT. The samples were characterized using XRD, SEM-EDX, and micro-Raman Spectroscopy. The change in reflectance of the samples after tarnish test is determined using UV–Visible reflectance spectroscopy. The mechanism behind the tarnish resistance was derived using Density Functional Theory (DFT) by comparing sulphur (S2) and Oxygen (O2) adsorption energies (BE) of the alloying elements. The lower value of S2 (BE)/O2 (BE) indicates better oxidation and tarnish resistance. The ratio ranges between 222 % (Pure Ag) and 132 % (for Ag-4.2Cu-2.8Zn-1.4Ge) and the p-p between Ge and O has contributed to the reduction in the ratio.

Influence of germanium concentration on the microstructure and optical transparency of terbium gallium garnet ceramics

AbstractIn recent years, transparent terbium gallium garnet (TGG) ceramics have garnered significant interest for their application in high‐power Faraday isolators. However, challenges in achieving high transparency have led researchers to explore the addition of various sintering aids as a key strategy to enhance the optical quality of TGG ceramics. Through this work, the effect of germanium (Ge) addition on the microstructure and optical transparency of TGG magneto‐optical ceramics was investigated. TGG powders were synthesized by the co‐precipitation method, and the source Ge was Ge ethoxide added through a ball‐milling step. Transparent TGG ceramics were prepared by air pre‐sintering combined with hot isostatic pressing post‐treatment and subsequent annealing. The ceramics containing 200 ppm Ge exhibit optimal transmittance of 81.3% at 1064 nm (a value of theoretical transmittance), the Verdet constant was −133.0 rad·T−1·m−1 at 633 nm. When the addition of Ge reaches 600 ppm, a secondary phase can be observed on the surface of ceramic. Subsequently, TGG ceramics prepared from 1425°C to 1500°C with 200 ppm of Ge were analyzed, which revealed that the optimal pre‐sintering temperature is 1450°C.

The Effect of Germanium Additions on the Mechanical Properties of Zn-Mg-Al Alloys

In this investigation, 0.19 wt.%–1.8 wt.% of Ge was introduced into a ternary Zn-Mg-Al alloy. The introduction of Ge had a significant impact on the microstructure, leading to the formation of Mg2Ge. The area fraction of the eutectic phase diminished with increasing Ge additions. Small-scale test techniques were utilised to evaluate the mechanical properties due to the changes in microstructure. Zn-Mg-Al alloys were found to be inherently harder compared to standard hot-dip Zn-containing 0.2 wt.% Al. The hardness and strength of the Zn-Mg-Al alloys decreased with the increase in Ge additions.

From experimentation to prediction: comprehensive study of dielectric properties through experimental research and theoretical modeling

This study discusses the experimental findings on the frequency & temperature influences on the dielectric (constant (ε1) and loss (ε2)) of some chalcogenide materials based on Se83Bi17 composition performed in the temperature range 303 K–393 K and frequency range (100–1000000 Hz). As the frequency increases, multiple polarization mechanisms contribute to the reduction of the dielectric constant. The addition of germanium (Ge) to a composition increases ε1 more than tellurium (Te). The dielectric loss decreases with frequency while increasing with temperature and AC conductivity. Understanding these behaviors is important for material characterization and applications in fields like electronics and solar cells. The theoretical section introduces adaptive neuro-fuzzy inference systems (ANFIS), which are utilized in the estimation of the dielectric characteristics of Se83Bi17 (SB), Se83Bi17Te5 (SB-T), and Se83Bi17Ge5 (SB-G). Experimentation-related data are a source of input. ANFIS model of the Takagi–Sugeno type has been trained. With MATLAB, the most effective networks are created. The outcomes of the ANFIS modeling are exceptional. The accuracy of the modeling process is due to the error values. This study demonstrates that the ANFIS technique can accurately anticipate the dielectric properties of the compositions under consideration when they are formed into thin films. The ANFIS can describe the experimental data of the dielectric (constant (ε1) and loss (ε2)) of some chalcogenide materials for all the mentioned temperatures and frequencies. This leads to using the ANFIS model to produce the dielectric (constant (ε1) and loss (ε2)) of some chalcogenide materials for various temperatures and frequencies which there are no experimental data yet to compare with.

Pt(II) complexes bearing P,N-donor ligands as catalysts in chemoselective hydrosilylation, hydrogermylation, and hydroboration of terminal alkenes

In this report, we present the synthesis of six novel neutral platinum complexes employing readily available P,N-donor ligands through a straightforward two-step procedure. Subsequently, we investigated their catalytic activity in the hydroelementation of terminal olefins, highlighting their versatile utility in material and natural product chemistry. The efficient addition of silicon, germanium, and boron hydrides to the CC bond at low catalyst loading occurred exclusively in an anti-Markovnikov manner. Furthermore, our substrate scope encompasses a wide range of aliphatic and aromatic alkenes, featuring substituents with varying electronic properties. In contrast to many previous Pt-complexes, our catalytic system displayed exceptional chemoselectivity towards other unsaturated functional groups, such as carbonyl and internal CC bonds. Notably, it also exhibited remarkable tolerance to hydroxyl, alkoxyl, silyl, and thioether moieties. Additionally, we accentuated the prowess of our catalyst, showcasing its capability to sustain consistent activity and selectivity throughout numerous catalytic cycles.

Enhancing performance of Sn–Ag–Cu alloy through germanium additions: Investigating microstructure, thermal characteristics, and mechanical properties

The conflict between strength and ductility has been a longstanding dilemma for metallic alloys. In this study, we introduce an innovative approach to significantly improve the overall performance concerning ultimate tensile strength (UTS) and elongation (EL%). This research explores the effects of adding germanium (Ge) into Sn− 2.0Ag− 0.7Cu (SAC207) solder alloys, delving into its impact on microstructure, thermal properties, ductility, and ultimate tensile strength. The findings revealed that adding Ge substantially reduces the eutectic temperature and undercooling within the solder, concurrently refining the β-Sn phase while expanding the eutectic regions. Furthermore, the formation of Ge phases within the solder matrix noticeably influences its mechanical properties. It is notable that introducing 0.5 wt% Ge into SAC 207 alloy leads to exceptional enhancements in both strength and ductility, with a remarkable tensile strength of 56.5 MPa and an elongation of 58.3%. These notable improvements can be attributed to the creation of a heterogeneous microstructure fortified by grain boundary strengthening, solid solution enhancement, and precipitation strengthening effects in solder alloys. The valuable insights gleaned from this research have significant implications for the advancement of the SAC 207 alloy in various applications and optimizing its manufacturing processes.

Electrochemical corrosion behaviour and corrosion mechanism of Sn-9Zn-xGe solder alloys in NaCl solution

The electrochemical corrosion behaviour and corrosion mechanism of Sn-9Zn-xGe alloy in 3.5 wt.% NaCl solution was investigated using electrochemical techniques combined with surface characterization techniques. The results showed that the alloy corrosion was mainly affected by the rupture of passivation film and Cl- migration along grain boundaries. Trace Germanium (Ge) addition refined the microstructure and improved the corrosion potential of the alloy. Solder alloys containing 0.6 wt.% Ge formed a uniform and dense passivation film on the corrosion surfaces, which reduced the corrosion rate and increased the corrosion resistance.

Saturation limit and p-type thermoelectric properties of RuAs2−xGex

Ruthenium arsenide is made p-type by the addition of germanium, and it exhibits a large substitution range without affecting the stability. A series of RuAs2−xGex with x = 0.02, 0.04, 0.08, 0.16, 0.32, and 0.64 shows the saturation limit of Ge to be between 0.16 and 0.32. The electrical contribution to the thermoelectric performance is greatly improved with a power factor of 1.03 mW/(m K2). However, the substitution does not affect the rigidity of the lattice, as the Debye temperature remains around 420 K, which means that the thermal conductivity remains high resulting in a modest maximum zT of 0.11.

KINETICS OF OXIDATION OF Ca–Ge SYSTEM MELTS BY AIR OXYGEN

With the introduction of complex alloys and metals – reoxidizers into liquid steel, their waste is observed, or more precisely, oxidation by the gas phase of the furnace. To select the optimal composition of complex deoxidizers, it is necessary to know the physicochemical laws of this process, which are little studied. To study the kinetics of oxidation of metal melts, the method of continuous sample weighing is used, which is usually used in the study of high-temperature corrosion of solid metals. The mechanism of interaction of liquid metals with oxygen is similar in nature to high-temperature gas corrosion of solid metals. In both cases, adsorption of gas molecules on the metal surface, nucleation, and then growth of an oxide film take place. In this work, the kinetics of oxidation of Ca-Ge melts with atmospheric oxygen was studied using thermogravimetry, IR spectroscopy, and X-ray phase analysis. It is shown that germanium additions up to 33.3 at % increase the resistance of melts to oxidation. An increase in temperature contributes to an increase in the rate of oxidation of melts of the Ca–Ge system. The process of oxidation of the investigated melts obeys the parabolic law. The true rate of oxidation is on the order of 10–4 kg · m–2 · s–1. The apparent activation energy of oxidation, depending on the composition of the alloys, is 39.8–526.7 kJ/mol. The products of melt oxidation are СaGe4О9 and GeО2. The mechanism of the influence of germanium on the kinetics of oxidation of Ca-Ge melts has been established. The CaGe4O9 oxide plays a dominant role in the formation of a protective oxide film.

Energy and Electronic Properties of Nanostructures Based on the CL-20 Framework with the Replacement of the Carbon Atoms by Silicon and Germanium: A Density Functional Theory Study.

We consider SinCL-20 and GenCL-20 systems with carbon atoms replaced by silicon/germanium atoms and their dimers. The physicochemical properties of the silicon/germanium analogs of the high-energy molecule CL-20 and its dimers were determined and studied using density functional theory with the B3LYP/6-311G(d,p) level of theory. It was found that the structure and geometry of SinCL-20/GenCL-20 molecules change dramatically with the appearance of Si-/Ge-atoms. The main difference between silicon- or germanium-substituted SinCL-20/GenCL-20 molecules and the pure CL-20 molecule is that the NO2 functional groups make a significant rotation relative to the starting position in the classical molecule, and the effective diameter of the frame of the systems increases with the addition of Si-/Ge-atoms. Thus, the effective framework diameter of a pure CL-20 molecule is 3.208 Å, while the effective diameter of a fully silicon-substituted Si6CL-20 molecule is 4.125 Å, and this parameter for a fully germanium-substituted Ge6CL-20 molecule is 4.357 Å. The addition of silicon/germanium atoms to the system leads to a decrease in the binding energy. In detail, the binding energies for CL-20/Si6CL-20/Ge6CL-20 molecules are 4.026, 3.699, 3.426 eV/atom, respectively. However, it has been established that the framework maintains stability, with an increase in the number of substituting silicon or germanium atoms. In addition, we designed homodesmotic reactions for the CL-20 molecule and its substituted derivatives Si6CL-20/Ge6CL-20, and then determined the strain energy to find out in which case more energy would be released when the framework breaks. Further, we also studied the electronic properties of systems based on CL-20 molecules. It was found that the addition of germanium or silicon atoms instead of carbon leads to a decrease in the size of the HOMO–LUMO gap. Thus, the HOMO–LUMO gaps of the CL-20/Si6CL-20/Ge6CL-20 molecules are 5.693, 5.339, and 5.427 eV, respectively. A similar dependence is also observed for CL-20 dimers. So, in this work, we have described in detail the dependence of the physicochemical parameters of CL-20 molecules and their dimers on the types of atoms upon substitution.

Experimental Study of the Electrochemical and Biological Properties of (Nb-1%Zr-xGe) Alloy for Biomedical Applications

Because of its relatively inert and unreactive surface, niobium seems to be especially attractive metal for use as a biomaterial. Mechanical property constraints, on the other hand, have limited the material's usage in this field. In terms of processing, microstructure, and mechanical characteristics, the (Nb-1 percent Zr) alloy is one of the most adaptable materials. Because of their features, such as reduced modulus of elasticity, excellent biocompatibility, and superior corrosion resistant than other alloys, these alloys have been frequently employed in biomedical applications, mostly substituting rigid textiles. This research focuses on recent discoveries in low modulus (Nb-1 percent Zr) based alloys with varied (0.5-6) wt. percent germanium additions for biomedical applications. Alloys were made in a steel mold using a powder metallurgy process, then sintered at 1200 degree centigrade for 6 hours. X-ray diffraction and mechanical characteristics such as wear, elastic modulus, compression, and Brinell hardness were utilized to examine the influence of germanium alloy additions. It has been discovered that increasing the germanium concentration increases porosity. Increased amount of germanium particles, on the other hand, enhances wear resistant, compressive strength, and micro-hardness. With applying additional loads for all alloying components concentration in germanium, the wear resistant reduced. The findings suggest that the alloy containing (0.5-6) wt. percent germanium particles has comparatively good mechanical and wear characteristics when compared to the base alloy, and it might be regarded acceptable for biomaterials applications due to its strong corrosion resistance.

Research on a novel chalcohalide glass and its physical optics properties

Two series of novel chalcohalide glasses varying on different molar percentages of cations and anions were prepared successfully. We experimentally investigated the physical optics properties of the chalcohalide hybrid glass (Ge-As-S-Se-I) system. The results show that the short-wavelength cut-off edge (λvis), linear refractive index (n0), and zero-dispersion-wavelength (ZDW) regularly decrease with the increase of anionic iodine mole percentage. And the addition of cationic germanium enhances the glass transition temperature (Tg), softening temperature (Tp) and crystallization temperature (Tx). Besides, a mono-index optical fiber was drawn successfully using the high temperature polymer as the protective layer, with a minimum loss of 1.91 dB/m at 2.6 μm. Supercontinuum (SC) covering 1.01 ∼ 8.32 μm was generated by pumping the 10-cm-long fiber at a femtosecond laser of 3.78 μm (∼150 fs, 1 kHz, 20 mW). This novel infrared (IR) glass shows great potential in many applications, such as defense military, spectroscopy, long-distanceremote sensing.

The ability of Mg2Ge crystals to behave as ‘smart release’ inhibitors of the aqueous corrosion of Zn-Al-Mg alloys

In-situ scanning vibrating electrode technique and time-lapse microscopy are used to investigate the influence of germanium additions (0.19–1.8 wt.%) on the corrosion performance of zinc-aluminium-magnesium model alloys immersed in 0.17 mol.dm−3 NaCl. The addition of Ge results in the formation of Mg2Ge and a decrease in the fractional area of eutectic phase. A 58 % decrease in SVET derived mass loss is achieved at 1.8 wt.% Ge. It is proposed that Mg2Ge crystals are anodically attacked and behave as reservoirs of Mg2+ ions. Mg(OH)2 is precipitated and local electrolyte pH stabilises to values at which the zinc surface is passive.

The Effect of Germanium Addition on the Lead-free Solder Alloys: A Short Review

The Restriction of Hazardous Substances (RoHS) has been enforced a law to restrict the use of hazardous materials in electronic and electrical industries. Hence, it leads to the development of lead-free solder among the electronic industry. SnAg, SnCu, SnAgCu, and SnZnBi solders are found to be alternatives to replace SnPb solder alloys. However, they still have many problems, such as large undercooling and large intermetallic compounds are still present in the solder alloys. Later, researchers come up with the idea of adding alloying elements to lead-free solders to further enhance the properties of lead-free solders. This review paper is aimed to analyze and summaries the effects of germanium (Ge) addition to lead-free solders focusing on its microstructure and thermal properties. The Ge has an almost similar crystal structure as pure tin (Sn), so it is expected that the properties of the lead-free solder could be enhanced by adding an appropriate amount of Ge. Nevertheless, Ge has a unique characteristic as it could act as an antioxidant agent in the lead-free solders.

Corrosion Behavior of Ternary Zr-25Ti-5Sn Alloy Doped with Ge as Biomaterials Implant in Simulation Body Fluid Solution

<p class="02abstracttext">Corrosion research of metal alloys of Zr-25Ti-5Sn and Zr-25Ti-3Sn-2Geas biomaterials has been carried out in fluid solution. Zr-25Ti-5Snalloy is a ternary metal alloy developed for hard tissue biomaterials. Zr-25Ti-5Sn and Zr-25Ti-3Sn-2Ge alloys is melted in electric arc furnace. After being melted Zr-25Ti-5Sn and Zr-25Ti-3Sn-2Ge were characterized by optical microscopy. Hardness testing was carried out by the hardness microvickers method to determine the effect of germanium addition on Zr-25Ti-5Sn alloys. Corrosion testing of ternary metal alloys Zr-25Ti-5Sn and Zr-25Ti-3Sn-2Ge was carried out by the Tafel polarization method using three electrode systems. From the results of microstructure examination with optical microscope, the microstructure found in the ternary metal alloy Zr-25Ti-5Sn and Zr-25Ti-3Sn-2Ge are parallel plates and dendritic. The hardness test results show that the addition of germanium to the Zr-25Ti-5Sn ternary alloy increased the hardness of the alloy. Corrosion test results on ternary alloy Zr-25Ti-5Sn and Zr-25Ti-3Sn-2Geindicated that corrosion resistance of Zr-25Ti-5Snincreased when no addition of Germanium to Zr-25Ti-5Snalloy.</p>

Role of refractory elements in near-alpha titanium alloys on high temperature mechanical properties

The effect of Tungsten (W), Tantalum (Ta) and simultaneous addition of Germanium (Ge) and Silicon (Si) on the microstructure evolution, tensile and creep properties of the near-alpha alloy Ti-5.7Al-3.9Sn-3.7Zr-0.7Nb-0.5Mo-0.35Si-0.05C have been investigated at high temperatures up to 650°C. Microstructural characterizations following solution treatment at 1050°C for 2 hours with oil quenching and aging treatment at 700°C for 2 hours followed by air cooling, highlighted that the additions of refractory elements such as W and Ta led to a decrease of both the volume fraction of the primary alpha phase (ap) and its average size. Tensile tests performed up to 650°C revealed a significant improvement in tensile strength with additions of W and Ta, even though a decrease of ductility has been also detected. Creep tests carried out at 600°C under a constant stress of 200 MPa pointed out that, refractory elements, Ge and Si have a beneficial effect on both primary and steady-state creep strain rates.

Soluble germanium addition to silicon-starved cultures of the diatom Cyclotella sp. limits β-chitin nanofiber formation

Diatoms are unicellular algae that make nanostructured, porous cell walls called frustules through uptake and biomineralization of soluble silicon (Si) to silica during the cell division process. After cell division, the diatom Cyclotella sp. also synthesizes and extrudes nanofibers composed of poly N-acetyl glucosamine (β-chitin) through conical pore structures called fultoportulae lining the rim of the frustule valve. The nanofibers are 50–60 nm in width and 40–80 μm in length. After cultivation of Cyclotella to the Si-starved state, nominally 80 fibers per cell (approximately 2 fibers per fultoportula) were produced following the final cell division. However, the co-addition of soluble Si and germanium (Ge) to Si-starved cultures Cyclotella sp. limited diatom growth to one cell division cycle and induced aberrations in the nanostructure of daughter frustule, including fusion of pore arrays and closure fortuportulae openings. This process led to a twofold reduction in the number of β-chitin nanofibers extruded per cell, although fiber length was not affected. These observations were consistent with a process where the parent frustule continued to form chitin nanofibers, whereas the aberrant daughter frustule did not. This study also demonstrated how diatom biomineralization processes can be harnessed to create novel biogenic nanostructured materials consisting of both Si-Ge oxide nanocomposites and pendant biopolymer nanofibers.

Influence of Germanium Addition on Optical Properties of As–Se Glasses

Present paper focus on the optical properties of Se62.5As37.5 and Se62.5As22 5Ge15 chalcogenide thin films prepared by vacuum evaporation method. The structural and stoichiometric properties of prepared glassy alloys were investigated by X-ray diffraction and energy dispersive X-ray spectroscopy. Addition of Ge at the cost of As increases the absorption and optical band-gap while the value of extinction coefficient decreases. The transmission spectrum (300–1100 nm) obtained by UV-Vis spectrophotometer were used to find the different optical constants. The increase of optical bandgap is explained based on Mott-Davis model assuming that there is decrease of localized states in prepared samples after addition of Ge in As–Se alloy which results in increase of optical bandgap.

Studies of high field conduction and resistive switching in Se78-xTe20Sn2Gex (0 ≤ x ≤ 6) bulk glasses using current-voltage characteristics

This paper investigates the role of Germanium addition on the electronic transport behavior of the parent Se78Te20Sn2 glass. For this, the multi-component glasses of Se78-xTe20Sn2Gex (0 ≤ x ≤ 6) system have been prepared by the melt-quench route. The samples having almost identical disc-shaped geometry are used for the current-voltage (I–V) characteristics at various temperatures having values less than the glass transition temperature in such pellets. Our investigation of the experimental data indicates the presence of resistive switching in parent glass that maintains for lower concentration (x = 2) of Ge additive. However, the quaternary glasses having higher concentration (x = 4, 6) of Ge show the high field conduction instead of resistive switching. The detailed studies show the signature of compensation effect in thermally activated resistive switching in ternary Se78Te20Sn2 and quaternary Se76Te20Sn2Ge2 glasses, while the Poole-Frenkel conduction is observed as the dominant mechanism of conduction in quaternary Se76Te20Sn2Ge2 and Se76Te20Sn2Ge2 glasses.