Mo Content Research Articles

Effect of ultrasonic impact treatment on the microstructure and properties of laser cladded CoCrFeNiMox high entropy alloy coatings

Ultrasonic impact technology was applied to improve the property of laser cladded CoCrFeNiMox (x = 0, 0.25, 0.5, 0.75) high entropy alloy coatings on the surface of low-carbon steel. The phase structures and the microstructural characteristics were studied in detail through X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The microhardness distributions, wear resistance, and corrosion resistance of the samples are illustrated using a microhardness tester, a micro-friction and wear tester, and an electrochemical test system. Single FCC phase solid solution was identified to be the main phase structure, with the interdendritic σ phase precipitating with the increasing Mo content. Although ultrasonic impact treatment did not change the phase composition of the high-entropy alloy (HEA) cladding coatings, evident plastic deformation and broken σ phase appeared near the surface of the impacted layers. Through the combined effects of dislocation, fine-grain, and dispersion strengthening, the microhardness of the CoCrFeNiMox coatings was improved after ultrasonic impact treatment. In addition, ultrasonic impact treatment decreased the surface roughness and increased the wear resistance, and the main wear mechanism of the impacted layers changed from fatigue spalling to abrasive wear. The wear mass of the ultrasonically impacted layers was approximately 92 % of the laser cladded CoCrFeNiMox coatings. Furthermore, ultrasonic impact treatment improved the corrosion resistance of the HEA coatings.

Enhanced Tribological Performance of Micro-Beam Plasma-Cladded Ni60 Coatings with Addition of Mo and Ag Lubricants in a Wide Temperature Range

In recent years, there has been significant attention on the application potential of medium and high-temperature self-lubricating composites as sliding parts in extreme environments. This study examines the effects of different Mo and Ag content on the composition and wear resistance of Ni60-cladded coatings at room temperature, 300 °C and 600 °C, while also analyzing their wear mechanism by studying the tribofilm. The results indicate that with an appropriate weight addition of Mo and Ag, one typical lubricant called Ag2MoO4 emerges. At room temperature, the cladding layer containing 5 wt.% Mo and 5 wt.% Ag exhibits a wear rate of 2.08 × 10−6 mm3/Nm, and an average coefficient of friction (COF) of 0.3410. These two are 85% and 11% lower than those of the Ni60 cladding layer, respectively. At 300 °C, MoO3 and Cr2MoO6 act as solid lubricants. Furthermore, at 600 °C, a MoSi2 and SiO2 film forms on the worn surface to prevent further oxidation of MoSi2 and enhance oxidation resistance. The main wear mechanism is adhesion wear. Under higher temperatures, the newly formed Ag2MoO4 in the composite cladding layer adopts a layered cubic spinel structure where low-energy Ag-O bonds preferentially break during friction processes, demonstrating excellent lubrication performance.

Natural variants of molybdate transporters contribute to yield traits of soybean by affecting auxin synthesis

Soybean (Glycine max) is a crop with high demand for molybdenum (Mo) and typically requires Mo fertilization to achieve maximum yield potential. However, the genetic basis underlying the natural variation of Mo concentration in soybean and its impact on soybean agronomic performance is still poorly understood. Here, we performed a genome-wide association study (GWAS) to identify GmMOT1.1 and GmMOT1.2 that drive the natural variation of soybean Mo concentration and confer agronomic traits by affecting auxin synthesis. The soybean population exhibits five haplotypes of the two genes, with the haplotype 5 demonstrating the highest expression of GmMOT1.1 and GmMOT1.2, as well as the highest transport activities of their proteins. Further studies showed that GmMOT1.1 and GmMOT1.2 improve soybean yield, especially when cultivated in acidic or slightly acidic soil. Surprisingly, these two genes contribute to soybean growth by enhancing the activity of indole-3-acetaldehyde (IAAld) aldehyde oxidase (AO), leading to increased indole-3-acetic acid (IAA) synthesis, rather than being involved in symbiotic nitrogen fixation or nitrogen assimilation. Furthermore, the geographical distribution of five haplotypes in China and their correlation with soil pH suggest the potential significance of GmMOT1.1 and GmMOT1.2 in soybean breeding strategies.

Improved microstructure and strength of Sn-Ag-Cu/Cu solder joint with Mo nanoparticles addition

A new type of lead-free composite solder has been prepared by adding Mo nanoparticles in Sn3.0Ag0.5Cu solder. Tensile strength tests were conducted on Sn3.0Ag0.5Cu/Cu joint and composite solder/Cu joints. The results indicated that the addition of Mo nanoparticles markedly improved the tensile strength of solder joint. when Mo concentration was between 0 and 1%, with the increase of Mo concentration, the tensile strength increased significantly. EBSD (Electron Back Scatter Diffraction) analysis of microstructure was conducted. It was concluded that Mo could significantly increase grain boundary length and dislocation density, reduce the size of the β-Sn phase.

Passivation and localized corrosion resistance of Al0.3Cr0.5Fe2MoxNi1.5Ti0.3 compositionally complex alloys: Effect of Mo content

Al0.3Cr0.5Fe2MoxNi1.5Ti0.3 (x = 0, 0.05, 0.15) FCC+L21 compositionally complex alloys are investigated using electrochemical and surface science methods in 0.1 M Na2SO4 and 0.1 M NaCl at pH 4 and 10. Mo is mainly found in the FCC phase and amplifies Al and Ti partitioning. The passive film is enriched in Cr(III), Ti(IV), Mo(IV)/Mo(VI), and (at pH 4) Al(III) with elemental fates tracked during film formation and dissolution. Mo presence does not enhance Cr or Ni passivation, instead promoting Ti(IV). Pitting and repassivation potentials increase at higher Mo concentrations, suggesting improved resistance to localized corrosion often initiated at FCC-L21 interfaces.

Iron-doped catalyst synthesis in heterogeneous Fenton like process for dye degradation and removal: optimization using response surface methodology

Iron-doped hydrochar can effectively remove the methyl orange dye (MO). In this study, iron-doped hydrochar (5% Fe@BC) was successfully synthesized through a two-step hydrothermal carbonization (HTC) process, using FeSO4.7H2O and sawdust. It was subsequently employed for MO removal. The characterization of the synthesized Fenton-like catalyst (5% Fe@BC) was conducted, using scanning electron microscopy, Fourier-transform infrared and X-ray diffraction techniques to confirm the presence of iron species. The effects of different operating parameters such as catalyst mass, H2O2 concentration, solution pH, organic pollutant concentration, and reaction temperature have been examined. The Box-Behnken design combined with three factors: catalyst mass X1, temperature X2, organic pollutant concentration X3. The response surface methodology coupled with Box-Behnken Design was used to optimize the key variables and response. With this approach, an exhaustive assessment of the variables influencing the optimization process was performed. A significant quadratic model was generated through analysis of variance with a P-value of 0.0001 and an R2 of 0.99. This confirms a strong relationship between the variables and the response, as well as a high level of model predictability. The optimum conditions were achieved with a catalyst mass of 0.5 g/L, a temperature of 35.5 °C, and an MO concentration of 50 mg/L. The result indicates that 93% of the discoloration efficiency was achieved within 60 min under the optimal conditions. Iron doping in the (5% Fe@BC) plays a crucial role in the degradation and removal of MO. Therefore, the 5% Fe@BC prepared from sawdust and iron salts (FeSO4·7H2O) through a two-step HTC process is an inexpensive and effective catalyst for removing organic pollutant from aqueous solutions, using heterogeneous Fenton-like process.

Distribution of molybdenum in soft tissues and blood of rats after intratracheal instillation of molybdenum(IV) sulfide nano- and microparticles

There is still little literature data on the toxicity and safety of the commonly used molybdenum (Mo) disulfide which is present in the working as well as living environments. Thus, an experiment was carried out involving rats, with single and repeated intratracheal exposure (in the latter case, 7 administrations at 2-week intervals with the analysis performed after 90 days) to lower (1.5 mg Mo kg−1 b.w.) and higher (5 mg Mo kg−1 b.w.) doses of molybdenum(IV) sulfide nanoparticles (MoS2-NPs) and microparticles (MoS2-MPs). The analysis of Mo concentrations in the tail and heart blood as well as in soft tissues (lung, liver, spleen, brain), after mineralization and bioimaging, was meant to facilitate an assessment of its accumulation and potential effects on the body following short- and long-term exposure. The multi-compartment model with an exponential curve of Mo concentration over time with different half-lives for the distribution and elimination phases of MoS2-MPs and MoS2-NPs was observed. After 24 h of exposure, a slight increase in Mo concentration in blood was observed. Next, Mo concentration indicated a decrease in blood concentration from 24 h to day 14 (the Mo concentration before the second administration), below the pre-exposure concentration. The next phase was linear, less abrupt and practically flat, but with an increasing trend towards the end of the experiment. Significantly higher Mo concentrations in MoS2-NPs and MoS2-MPs was found in the lungs of repeatedly exposed rats compared to those exposed to a single dose. The analysis of Mo content in the liver and the spleen tissue showed a slightly higher concentration for MoS2-NPs compared to MoS2-MPs. The results for the brain were below the calculated detection limit. Results were consistent with results obtained by bioimaging technique.

Influence of dual Mo and Ru ion implantation on the characteristics of commercial TiN-TiAlN-coated WC-10wt%Co-0.5wt%Cr3C2 face milling inserts

The influence of simultaneous dual Mo + Ru ion implantation into commercial TiN and TiAlN hard metal coated WC-10wt%Co-0.5wt%Cr3C2 face milling inserts were investigated at dosages from 5 × 1015 to 1 × 1017 ions/cm2 at 100 keV acceleration voltage. Various characterisation techniques such as field emission scanning electron microscopy, energy dispersive spectroscopy, atomic force microscopy, glancing incident X-ray diffraction, and X-ray photoelectron spectroscopy were used to characterise the microstructure and topography of the as-received and ion implanted samples. The micro-hardness and residual stresses were also determined. Face milling tests were conducted to determine the effect of ion implantation on the wear rate. It has been observed that the dual Mo + Ru ion implantation with a biased Mo content extended 1000 nm into the dual TiN/TiAlN layer with significantly improved microhardness and increased anisotropy between the σ11 and σ22 stress components of the substrate, indicative of related effects in the coatings. The strengthening effect of Ru was observed at all ion implantation dosages even though wt% of Ru was significantly lower than the wt% of Mo. There were no visible changes to the microstructure of the substrate, but the presence of Mo and MoO2 chemical phase contents were observed through XPS. All the ion implantation dosages improved machining performance as the wear rate of the ion implanted face milling inserts was lower than that of as-received TiN and TiAlN coated WC-10wt%Co-0.5wt%Cr3C2 face milling inserts.

Sigma‐Phase Distribution in 2507 Super Duplex Stainless Steel Continuous Casting Slabs

The sigma‐phase distribution in a 2507 super duplex stainless steel continuous casting slab is analyzed using microstructural analyses and thermodynamic calculations. The sigma phase contains high Cr and Mo contents, and precipitates along the phase boundary between austenite and ferrite and grows toward the interior of the ferrite phase in the continuously cast slab. The sigma‐phase fraction at the center of the width direction is higher than that in the one fourth width. Furthermore, the sigma‐phase fraction at the center of the thickness direction is higher than those at the upper and lower surfaces, which is due to the lower cooling rate at the center. The Brinell hardness (HB) at the center increases to 313 HB with an increasing sigma‐phase fraction. The sigma‐phase fraction at the one fourth thickness near the lower surface is higher than that at the one fourth thickness near the upper surface at the same cooling rate. Additionally, Mo and Ni are severely segregated in this zone. A higher Mo content influences the precipitation and stabilization of the sigma phase. Furthermore, Scheil–Gulliver calculations indicate that compositional segregation results in an increase in the sigma‐phase precipitation temperature range.

THE EFFECT OF BATH TEMPERATURE ON THE STRUCTURE AND TRIBOLOGICAL BEHAVIOR OF ELECTROLESS NI-B–MO COATINGS OBTAINED FROM STABILIZER-FREE BATH

Conventional electroless Ni–B–Mo (ENB–Mo) deposits are formed using hazardous lead or thallium-containing solutions, which must be removed. In this study, ENB–Mo deposits were developed in a bath free of stabilizers and harmful heavy metals. This study estimates the effect of variation of coating bath temperature on tribological performance of ENB–Mo coating developed over AISI 1040 steel. The chosen bath temperatures were [Formula: see text]C, [Formula: see text]C, and [Formula: see text]C to achieve ENB–Mo coating with varying B and Mo content. The 12–15 [Formula: see text]m thick coating was uniform. In comparison to steel substrate, all of the coatings show enhanced corrosion resistance. In the as-deposited state, coatings were mixed amorphous and nanocrystalline with peak of Fe overlapping with Ni. Moreover, TGA results revealed that inclusion of molybdenum enhanced coatings thermal stability. The worn specimens at [Formula: see text]C reveal development of shielding tribo-oxide coatings and existence of microstructural changes. At high working temperatures ([Formula: see text]C), wear debris also has a major impact on tribological mechanisms of coatings. Correlation between microstructure, tribological behavior, and corrosion resistance have also been conducted for ENB–Mo coatings.

Electrodeposition of crack-free and amorphous Ni-Mo alloys with high Mo content from gluconate baths

In this article, electroplated Ni-Mo alloys with high Mo content from gluconate baths are presented. Specifically, the influence of current density on the electrodeposition process, which produced crack-free Ni-Mo alloys with high Mo content, was evaluated. Commonly, Ni-Mo electrodeposition is performed in citrate solutions, as citrate ions promote coordination compounds with greater stability compared to mono and bivalent ligands. However, due to the high internal stress caused by Mo in the coating when its content is very high, microcracks are formed along the surface, causing defects in the deposit. Gluconate baths have been proven to produce crack-free alloys, even when current density is high. The deposits were evaluated for chemical composition by Energy-Dispersive X-ray Specrometry (EDS) and surface morphology by electron microscopy using a Scanning Electron Microscope (SEM). Furthermore, the deposition process was evaluated for current efficiency, and a reaction mechanism was proposed based on observations acquired by other authors. The highest Mo content obtained was 43% by weight. The highest current efficiency was 26%, obtained at 30 mA/cm².

Physical, mechanical, and corrosion properties of Ti–12Mo and Ti–15Mo alloys fabricated by elemental blend and mechanical alloying techniques

Ti–Mo alloys have received increased attention and concern in several applications, especially in biomedical, because of their appropriate properties, non-toxicity, and reasonable cost. This work investigated the different Mo powder content (12 and 15 wt%) fabricated by elemental blended and mechanical alloying. The microstructure, density, microhardness, compressive, wear, and corrosion properties were characterized. It was found that the volume fraction of β-phase increases with increasing Mo content to around 85%, mainly due to the robust β-phase stabilizer effect. Moreover, the microhardness and compressive properties were enhanced with Mo addition and MA fabrication by 11.5 and 27%, respectively, mainly due to solid solution strengthening, plastic deformation, high dislocations, and lattice defects. However, the strain at failure decreased with decreasing sintered density and increasing porosity. From this study, the corrosion rate decreased with decreasing the porosity, reaching 0.226 × 10−3 mm/year for Ti–12Mo alloy fabricated by elemental blend with a minimum porosity of 3.6%. Ti–Mo alloys can also tolerate properties and impurities, making them suitable for biomedical applications.

One-pot synthesis of MoO3-ZrO2 solid acid catalyst for solvent-free solketal production from glycerol

Glycerol acetalization to solketal is a promising method of increasing the additional value of glycerol, which is a by-product in biodiesel industry. In this work, a series of mesoporous x-MoO3-ZrO2 (x = Mo/Zr) solid acid catalysts with controllable Mo contents were designed and synthesized for the acetalization of glycerol. As important influence factors of solid acid catalysts, the mesoporous structure and existential state of Mo species were systematically investigated. Results show that Mo species were introduced as planned and existed in a homogeneously dispersed state in MoO3-ZrO2 materials. The acidic properties of MoO3-ZrO2 were explored through NH3-TPD and pyridine-chemisorbed FT-IR spectroscopy, and the formation of Brønsted and Lewis acid sites was confirmed by density functional theory calculations. Given their excellent acidity, MoO3-ZrO2 catalysts were employed for the acetal reaction of glycerol. Among the tested catalysts, the 20 %-MoO3-ZrO2 catalyst exhibited the optimal catalytic performance and reusability, achieving a conversion of 89 % for glycerol and a selectivity of 97 % for solketal. Consequently, MoO3-ZrO2 is a green solid acid catalyst with promising applications in solvent-free solketal production from glycerol.

Abstract 15121: Bioresorbable Molybdenum Electrodes: Towards a Novel Generation of Temporary Epicardial Pacing Wires

Introduction: Cardiac pacing with temporary epicardial pacing wires (TEPW) is used to treat rhythm disturbances after cardiac surgery. Removal is recommended on day 4-7. Occasionally, TEPW cannot be mechanically extracted, have to stay in the thorax and may rarely cause serious complications like migration and infection. We aim to develop novel, bioresorbable TEPW that will dissolve over time even if postoperative removal is unsuccessful. Methods and Results: We manufactured prototypical braided molybdenum (Mo) leads (16 Mo wires of 40 μM diameter each, length 18 cm for ex-vivo, 7.5 cm for in-vivo trials) coated with the biodegradable polymers poly(lactide-co-glycolic acid) (PLGA, inner coating) and polycaprolactone (PCL, outer coating) for shaping and electrical insulation. Mo electrodes showed similar pacing and sensing properties to conventional steel electrodes (Osypka) in Langendorff-perfused rat hearts, even with somewhat lower stimulation thresholds. In artificial body fluid at 37°C, polymer-coated Mo electrodes dissolved at a rate of 1.6 ± 0.3 μg/cm 2 ·d (n=5) compared to uncoated electrodes with 30.3 ± 0.8 μg/cm 2 ·d (n = 4, p < 0.001). Assessing apoptosis and necrosis in human cardiomyocytes and cardiac fibroblasts, we detected no toxicity at Mo concentrations up to 0.52 mM. To test Mo TEPW in vivo, we sutured them epicardially onto the anterior wall of hearts of female Wistar rats, led them out of the thorax and placed them in a subcutaneous pocket. We tested electrophysiological properties directly after implantation, after two weeks and one month. Mo electrodes showed similar pacing and sensing properties directly upon implantation and after two weeks. After one month, all but one pair of Mo electrodes were mechanically broken at their exit from the thorax, the site of assumedly highest mechanical stress. Conventional steel TEPW had similar electrical properties following implantation, after two weeks and one month with no signs of breakage. Conclusion: We demonstrate that Mo TEPW can feasibly be used for epicardial pacing in vivo for up to two weeks. These findings represent an important step in the development of bioresorbable TEPW as a novel and even safer approach to temporary epicardial pacing.

Evolution in microstructure and tribological behavior of laser cladded MoxNbTiZr high-entropy refractory alloy coatings with varying Mo content

The effect of the Mo element on the Ni-Ti-Zr refractory high-entropy alloy (RHEA) coatings synthesized by laser cladding were explored in terms of microstructural evolution and tribological behavior assessed by material characterization techniques and drying sliding wear tests. The findings reveal that MoxNbTiZr RHEA coatings, comprising of body center cubic (BCC) matrix phase and several hexagonal close packed (HCP) phases, have a dendrite microstructure with Mo, Nb-rich dendritic region (DR) and Zr-rich interdendritic region (IR), affected by Mo-induced thermodynamic instability. The micro-segregation between DR and IR becomes serious by the synergy effect of melting point difference, diffusion rate, and mixing enthalpy. The microhardness of the RHEA coating has a linear relationship with Mo content, with the highest value of 732.67 HV at x = 1.0. Nanotwins induced by residual stress, high cooling rate, solid-solution strengthening, fine-grain strengthening, and second-phase strengthening, cause microhardness improvement. Due to the generation of the destructive oxide layer and rising coating brittleness, the wear rate rises from 1.66 × 10−4 mm3/(N·m) to 3.75 × 10−4 mm3/(N·m). The wear mechanism of the MoxNbTiZr coatings shifts from oxidation wear to abrasive wear and eventually to three-body abrasion and severe brittle micro-peeling. Among these coatings, Mo0.6NbTiZr exhibits the optimal performance with excellent comprehensive characteristics.

High-strength and high-toughness austenitic stainless steels based on type 316LN at 4.2 K

High-strength and high-toughness prototype steel forgings, N2, N3, and N4, were developed based on type 316LN as a cryogenic structural material. By extrapolating the proportional relationship between carbon plus nitrogen content (C + N) and 0.2 % proof stress (σ0.2) in the range of approximately 0.10–0.25 mass% C + N content, the C + N content was successfully designed to achieve the target σ0.2. To suppress the degradation of the plane-strain fracture toughness (KIC(J)) while increasing the nitrogen solid-solution content, the alloying level was designed by considering the stability of the austenite phase and stacking fault energy. The steel forgings showed a good balance of strength and toughness at 4.2 K, i.e., N2 (σ0.2 = 1142 MPa, KIC(J) = 228 MPa√m), N3 (σ0.2 = 1226 MPa, KIC(J) = 219 MPa√m) and N4 (σ0.2 = 1296 MPa, KIC(J) = 215 MPa√m). The σ0.2 and KIC(J) of ITER-grade 316LN (316LNL, 316LNM, and 316LNH) thick plates with low interstitial (C + N) content of 0.13–0.17 mass% were also evaluated at 4.2 K. Then, the effects of nitrogen content on strength and fracture toughness were successfully clarified in the full range of interstitials concentrations. An alloy design with higher Ni, Mn, and Mo contents in the chemical composition range of 316LN would be desirable for improving the fracture toughness by increasing σ0.2 due to the higher nitrogen content.

Effect of Mo addition on the microstructure and high-specific tensile strength of Fe–Mn–Al–Ni–C ferrous medium-entropy alloy

Molybdenum (Mo) is known to play various roles in ferrous materials, including promoting lattice distortion and forming different types of precipitates. In this study, Mo was added to the Fe–Mn–Al–Ni–C lightweight medium-entropy alloy system, and its effects on microstructure and tensile properties were investigated in comparison to the Mo-free counterpart. The addition of Mo retarded the kinetics of recrystallization and led to the precipitation of M6C-type carbides. In terms of tensile properties, the addition of Mo improved the strength of the alloy by enhancing solid solution strengthening and precipitation strengthening. In particular, the Mo-added alloy, annealed at 800 °C for 7.5 min, exhibited a yield strength of 1274 MPa and an ultimate tensile strength of 1550 MPa. This corresponds to a specific ultimate tensile strength of approximately 218 MPa g−1 cm3, along with a uniform elongation of ∼8.5 %. The Mo content in the solid solution and the presence of Mo-rich M6C-type carbides also contributed to high back stress hardening, which enhanced the alloy's ability for strain hardening and resulted in reasonable uniform elongation.

Effects of Mo doping on the phase transformation behaviors and the magnetic properties of rare-earth-free MnBi alloy

The high-performance rare-earth-free low-temperature phase Mn–Bi-based permanent magnet alloys (LTP-MnBi) have gained widespread attention, but it still presents a challenge. Here, the LTP-MnBi alloy with Mo element doping was prepared by using arc-melting and subsequent high-vacuum annealing. The crystalline structure, phase transformation behavior, and magnetic properties were systematically investigated. The result showed that Mo element doping significantly improved the stability of the LTP in MnBi alloy. The investigation revealed that the disparity in atomic radius between Mo and Mn, Bi elements played a pivotal role in the formation and stability of the LTP-MnBi. With the increase of Mo content in the LTP-MnBi alloy, the coercivity value remarkably increased from 8.1 kOe to 11.7 kOe with a decrease of saturation magnetization from 71.6 emu/g to 56.5 emu/g, and the maximum energy product gradually reduced from 10.6 MGOe to 7.9 MGOe. The underlying mechanism revealed that magnetic properties were closely related to the fraction and crystal structure of LTP-MnBi. Therefore, magnetic properties of Mo-doped MnBi alloy make them an attractive candidate among the rare-earth-free permanent magnets.

Effect of Mo Content on Friction and Wear Properties of Fe-Mn-Al-C Alloys Under Different Working Conditions

For this study, Fe-25Mn-9Al-8Cr-1C-xMo alloys (x = 0, 0.1, 0.2, 0.3, 0.4 wt%) were prepared by mechanical alloying combined with vacuum hot-pressing sintering. The corresponding microstructure, mechanical properties, and friction and wear properties under different working conditions (dry friction, oil lubrication and sulfur-containing boundary lubrication) of materials were studied. The results show that the Fe-25Mn-9Al-8Cr-1C alloy is mainly composed of the austenite phase, Cr7C3 phase, and a small amount of a-Al2O3 phase. After adding Mo element, the Fe2MoC phase appears. With the increase of Mo content, the tensile strength and elongation of the alloys increase first and then decrease. In particular, when the Mo content is 0.3 wt%, an excellent combination of strength and toughness is obtained. The product of strength and elongation of the Fe-25Mn-9Al-8Cr-1C-0.3Mo alloy reaches a maximum value of 3.69 GPa·%, which is improved by 158.04% compared with the matrix alloys. With the increase of Mo content, the average friction coefficient and volume wear rate of the alloys show a trend of first decreasing and then increasing under different working conditions. Also, the average friction coefficient and volume wear rate of the alloy with 0.3 wt% Mo reach a minimum value, especially under the condition of sulfur-containing boundary lubrication. The average friction coefficient and volume wear rate of Fe-25Mn-9Al-8Cr-1C-0.3Mo alloy are 0.051 and 0.222 × 10−4 mm3·N−1·m−1, respectively, which are 40.69% and 46.38% lower than those of the matrix alloys.

Nutrient Content in Ylang-Ylang (Cananga odorata (Lam.) Hook.f. & Thoms., Annonaceae) Cultivated in Ecuador

Ylang-ylang (<em>Cananga odorata</em> Hook.f. & Thoms.) is cultivated in many tropical areas of the world for the multiple applications of the essential oil extracted from its flowers. The aim of this work was to determine the concentrations of macro-nutrientes and micro-nutrients in the different ylang-ylang organs in two treatments, without fertilization and with commercial fertilization, based on a nutritional analysis of the soil of a production farm located in Chongón, Guayas, Ecuador. The concentrations of N, P and Mg were significantly higher in the treatment with fertilization (16.82; 2.96; 3.81 vs. 14.63; 2.39; 3.12 g/kg, respectively). Concerning micronutrients, in the treatment with fertilization, Mn, Cu and Mo concentrations were significantly higher (73.00; 13.50; 1.28 vs. 44.96; 9.08; 0.50 mg/kg), while Cl concentration was significantly lower (1692.58 vs. 3488.25 mg/kg). Significant differences were also found in nutrient concentration as a function of organs. The <em>C. odorata</em> N, P, K, Ca, Mg and S extraction is 30.83; 3.46; 12.87; 25.50; 4.85 and 3.35 kg/ha, respectively. Higher concentrations of N, Ca and K are suggested for this crop. These results contribute to the improvement of the quality of fertilization in the ylang-ylang cultivation.