Boron Content of Alfalfa as Influenced by Boron Supply1

1952 ◽  
Vol 16 (1) ◽  
pp. 60 ◽  
Author(s):  
W. T. Dible ◽  
K. C. Berger
Keyword(s):  
Boron Content

scholarly journals Pressure effect of the mechanical, electronics and thermodynamic properties of Mg–B compounds A first-principles investigations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
GuoWei Zhang ◽  
Chao Xu ◽  
MingJie Wang ◽  
Ying Dong ◽  
FengEr Sun ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
First Principles ◽  
Boron Content ◽  
Structural Parameters ◽  
Debye Model ◽  
Total Density ◽  
First Principle ◽  
Volume Deformation ◽  
Temperature And Pressure ◽  
Total Density Of States

AbstractFirst principle calculations were performed to investigate the structural, mechanical, electronic properties, and thermodynamic properties of three binary Mg–B compounds under pressure, by using the first principle method. The results implied that the structural parameters and the mechanical properties of the Mg–B compounds without pressure are well matched with the obtainable theoretically simulated values and experimental data. The obtained pressure–volume and energy–volume revealed that the three Mg–B compounds were mechanically stable, and the volume variation decreases with an increase in the boron content. The shear and volume deformation resistance indicated that the elastic constant Cij and bulk modulus B increased when the pressure increased up to 40 GPa, and that MgB7 had the strongest capacity to resist shear and volume deformation at zero pressure, which indicated the highest hardness. Meanwhile, MgB4 exhibited a ductility transformation behaviour at 30 GPa, and MgB2 and MgB7 displayed a brittle nature under all the considered pressure conditions. The anisotropy of the three Mg–B compounds under pressure were arranged as follows: MgB4 > MgB2 > MgB7. Moreover, the total density of states varied slightly and decreased with an increase in the pressure. The Debye temperature ΘD of the Mg–B compounds gradually increased with an increase in the pressure and the boron content. The temperature and pressure dependence of the heat capacity and the thermal expansion coefficient α were both obtained on the basis of Debye model under increased pressure from 0 to 40 GPa and increased temperatures. This paper brings a convenient understanding of the magnesium–boron alloys.

Electroless Plating of Transition Metal Boride with High Boron Content as Superior HER Electrocatalyst

ChemCatChem ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3068-3075 ◽  
Author(s):  
Ruiqi Zhang ◽  
Huixiang Liu ◽  
Chenfeng Wang ◽  
Lincai Wang ◽  
Yanjing Yang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Electroless Plating ◽  
Boron Content ◽  
Metal Boride ◽  
High Boron

EFFECT OF AMMONIA SOLUTION ON COMPOSITION, STRUCTURE AND MAGNETIC PROPERTIES OF CHEMICALLY PREPARED Co-B NANO-PARTICLES

2012 ◽  
Vol 05 ◽  
pp. 134-141
Author(s):  
HOOMAN SABAROU ◽  
ABOLGHASEM ATAIE
Keyword(s):  
Magnetic Properties ◽  
Boron Content ◽  
Fine Particles ◽  
Chemical Reduction ◽  
Amorphous Structure ◽  
Ammonia Solution ◽  
Nano Particles ◽  
Reagent Solution ◽  
Sem Images ◽  
Composition Structure

In this study, the effect of ammonia solution addition as a pH adjusting component on the thermal behavior, phase composition, morphology, and magnetic properties of reduced Co - B nano-particles fabricated by chemical reduction route have been studied using DSC, XRD, SEM, and VSM techniques, respectively. Chemical composition of the samples was measured by ICP. The ICP results showed that basic pH of reagent solution, derived from utilizing ammonia solution, caused the boron content to decrease. XRD results indicated an amorphous structure for both samples synthesized with and without ammonia solution. Analysis of the DSC results showed that crystallization behavior has dramatically altered, owing to utilize ammonia solution. While the sample synthesized without ammonia solution showed three distinctive exothermic peaks at 216,470, and 540°C, the sample synthesized in the presence of ammonia solution exhibited only two exothermic peaks at 235 and 470°C and one endothermic peak at 370°C. SEM images reveal that the samples have a net- like morphology and the net is formed by many interconnected spherical fine particles with sizes less than 100 nm. Saturation magnetization of the sample synthesized in the presence of ammonia solution has improved significantly, probably due to the less amount of boron.

Nd2Fe17 nanograins effect on the coercivity of HDDR NdFeB magnets with low boron content

2012 ◽  
Vol 19 (3) ◽  
pp. 236-239 ◽  
Author(s):  
Ai-zhi Sun ◽  
Shen Wu ◽  
Wen-huan Xu ◽  
Jin Wang ◽  
Qian Zhang ◽  
...  
Keyword(s):  
Boron Content ◽  
Ndfeb Magnets

scholarly journals Tribological Performance of CoCrMo Alloys with Boron Additions in As-Cast and Heat-Treated Conditions

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 355
Author(s):  
Marco A. L. Hernandez-Rodriguez ◽  
Diego E. Lozano ◽  
Gabriela M. Martinez-Cazares ◽  
Yaneth Bedolla-Gil
Keyword(s):  
Boron Content ◽  
Tribological Performance ◽  
Secondary Phases ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
Hardness Tests ◽  
Heat Treated ◽  
Cocrmo Alloys ◽  
Cast Condition ◽  
Ball On Disc

The present study evaluates the effect of boron additions on the tribological performance of CoCrMo alloys. The alloys were prepared with boron ranging from 0.06 to 1 wt%. The materials were characterized using metallographic techniques, scanning electronic microscopy, and roughness and hardness tests. Tribological evaluation was made by means of ball-on-disc tests for sliding distances of 4, 8 and 12 km. The samples were in the as-cast condition and after a heat treatment at 1200 °C for 1 h, finished by water quenching. The results showed that wear resistance was influenced by the microstructure and the number of secondary phases. The volume loss decreased as the boron content increased. Due to hard phases, abrasion wear was observed. Delamination fatigue was also detected after long sliding distances. Both wear mechanisms diminished in higher boron content alloys.

The structure, phase composition, and residual stresses of diffusion boride layers formed by thermal-chemical treatment on the die steel surface

2021 ◽  
Vol 23 (2) ◽  
pp. 147-162
Author(s):  
Undrakh Mishigdorzhiyn ◽  
◽  
Nikolay Ulakhanov ◽  
Aleksandr Tikhonov ◽  
Pavel Gulyashinov ◽  
...  
Keyword(s):  
Phase Composition ◽  
High Temperature ◽  
Low Temperature ◽  
Residual Stresses ◽  
Diffusion Layer ◽  
Chemical Treatment ◽  
Steel Surface ◽  
Boron Content ◽  
Die Steel ◽  
Temperature Mode

Introduction. Control and management of technological residual stresses (TRS) are among the most critical mechanical engineering technology tasks. Boriding can provide high physical and mechanical properties of machine parts and tools with minimal impact on the stress state in the surface layers. The purpose of this work is to determine the temperature modes of diffusion boriding, contributing to a favorable distribution of TRS in the surface layer of die steel 3Kh2V8F. The paper considers the results of studies on the TRS determination by the experimental method on the UDION-2 installation in diffusion layers on the studied steel surface. Boriding was carried out in containers with a powder mixture of boron carbide and sodium fluoride as an activator at a temperature of 950 °C and 1050 °C for 2 hours. The obtained samples of steels with a diffusion layer were examined using an optical microscope and a scanning electron microscope (SEM); determined the layers' microhardness, elemental, and phase composition. The experiments resulted in the following findings: as the boriding temperature rose from 950 °C to 1050 °C, the diffusion layer's thickness increased from 20 to 105 μm. The low-temperature mode of thermal-chemical treatment (TCT) led to the formation of iron boride Fe2B with a maximum boron content of 6 % and a microhardness up to 1250 HV. A high-temperature mode resulted in FeB formation with a top boron content of 11 % and a microhardness up to 1880 HV. Results and Discussions. It is found that boriding at 950 °C led to a more favorable distribution of compression TRS in the diffusion layer. However, significant TRS fluctuations in the diffusion layer and the adjacent (transitional) zone could affect the operational properties after TCT at a given temperature. An increase in the TCT temperature led to tensile TRS's appearance in the layer's upper zone at a depth of up to 50 μm from the surface. Despite tensile stresses on the diffusion layer surface after high-temperature TCT, the distribution of TCT is smoother than low-temperature boriding.

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