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1

Mechanical properties and quantum mechanical simulations of natural rubber composites with cerium complexes under aging conditions

Li Yilin, Liu Yonggang, Hao Wei, Liu Zhaogang, Zhang Wentao, Hu Yanhong, Wu Jinxiu

Materials Science Poland

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2024

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Vol. 42, No. 1

158--170

EN

Enhancing the service life of natural rubber (NR) products, including antioxidants, is crucial to prevent rubber degradation and enhance its oxidation resistance. Phenolic antioxidant 2246 and cerium complex of p-amino salicylic acid (PAS-Ce) are utilized as NR antioxidants. Numerous studies have qualitatively analyzed the antioxidant mechanisms of these compounds. Building upon this perspective, this study quantitatively assessed the protective mechanisms of these antioxidants by combining experimental data with molecular simulations. Additionally, it compared their impacts on the thermal oxidative aging performance of NR. The findings revealed that the PAS-Ce/NR system exhibited the highest mechanical performance retention following multiple days of thermal-oxidative aging. Analyzing the PAS-Ce/NR system through ATR-FTIR and DTA techniques demonstrated that it had the lowest C=O content after thermal-oxidative aging. Furthermore, calculating the activation energy required for thermal-oxidative aging decomposition using the Kissinger and FWO methods indicated that PAS-Ce/NR had the highest activation energy, suggesting superior inhibitory effects against thermal-oxidative aging. Quantum mechanical simulations also illustrated that the dissociation energy of the O-H bond in antioxidants 2246 and PAS-Ce was lower than that of the C-H bond in NR. However, PAS-Ce exhibited a quicker capture of radical species, effectively delaying the oxidation reaction rate of NR molecular chains and thus more efficiently inhibiting the aging process. These insights contribute significantly to comprehending the antioxidative mechanisms in NR aging.

2

Substitution mechanism of rare earths at fluorapatite characteristic sites : experimental and computational calculations

Xie Jun

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 2

art. no. 163418

EN

Rare earths (REs) containing phosphate rock is a potential REs resource. The unclear occurrence mechanism of REs in phosphorite limits its further development and utilization. Fluorapatite (FAP) is the main REs-bearing target mineral in phosphorite, the microscopic mechanism of REs entering FAP still needs to be further studied from the electronic scale. In this paper, the doping mechanism of REs in FAP was studied by experiment combined with GGA+U calculation. The XRD, SEM, and FT-IR characterization results of hydrothermal synthesis products showed that REs (La, Ce, Nd, and Y) entered FAP crystal, and one of every 20 Ca atoms was replaced by a REs atom. The GGA+U calculation indicated that La-O/F, Ce-O/F, Nd-O/F, and Y-O/F were ionic bonds in general, and the bonding strength of La-O/F, Ce-O/F, Nd-O/F, and Y-O/F increased gradually with atomic number. The substitution difference of La, Ce, Nd, and Y was mainly caused by the gain and loss of electrons in f and d orbitals. The substitution mechanism of REs at the characteristic sites of Fap was studied, which provided a theoretical reference for the selective recovery of REs from phosphorus blocks.

3

Mineralogical characteristic and beneficiation evaluation of rare earth carbonate wall rock

Gao Chunqing, Yan Guoying, Wang Hailiang, Luo Hongzhen, Zhang Lin, Yang Hanxu, Xu Jian

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 1

art. no. 161300

EN

In order to rationalize the development and utilization of the wall rock discarded during rare earth mining, chemical analysis, inductively coupled plasma-atomic emission spectroscopy, X-ray diffraction analysis, artificial panning, optical microscope analysis, mineral liberation analysis and energy-dispersive spectroscopy were used to study the process mineralogy of the wall rock. The results show that the main useful elements in the rare earth wall rock were iron, light rare earth elements, fluorine and niobium. Iron was mainly occurrence as magnetic iron in magnetite, rare earth elements in bastnaesite and monazite, fluorine as a independent mineral in fluorite and niobium in columbite. The main useful minerals were finely disseminated, with magnetite (48.16%), bastnaesite (49.04%), monazite (42.18%), fluorite (39.30%) and columbite (63.26%) distributed in -0.030 mm particle size. The useful minerals were evaluated separately for beneficiation based on the process mineralogical characteristics of the rare earth wall rock, and the results showed that magnetite, rare earth and fluorite resources could be effectively recovered using magnetic separation, flotation, gravity concentration and leaching enrichment methods. The sequential recovery of iron, rare earth, fluorine and niobium elements produces iron concentrate (65.40% TFe at recovery of 38.03%), rare earth concentrate (50.66% REE at recovery of 62.73%), fluorite concentrate (95.23% CaF2 at recovery of 40.34%) and niobium iron ore concentrate (1.63% Nb2O5 at recovery of 5.56%). This study provides recommendations for the rational development and utilization of rare earth wall rock and provides reasonable levels of recovery predictions.

4

Investigate the Metallurgical, Degradation Behavior, and Mechanical Characteristics of a Novel Magnesium Alloy

Al Khaqani Baraa H., Dawood Nawal Mohammed

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 5

302--312

EN

Today, the use of magnesium alloys in medical applications as a decomposing material is extensive, so a new magnesium alloy Mg-2Al-1Nd was prepared by an investment-casting method in a medium protected from atmospheric oxygen. One of the rare elements, Nd, was added to improve the microstructural and mechanical properties and corrosion resistance in simulated blood plasma media. The XRF test determined the chemical characterization elements, the SEM test was used to identify the distribution of phases and their shape inside the base before and after heat treatment, and the XRD test was conducted to determine the type of phases that formed and the effect of these phases on other properties was studied. Also, hardness was measured using Vickers microhardness, in which the improvement rate was 75%, and a compression test to determine the mechanical properties of the prepared alloy found that the modulus of elasticity was 42GPa.To study its corrosive behavior inside the human body, a test was conducted on corrosion by the Tafel method to measure corrosion resistance in simulated blood plasma solution, Where the value of the corrosion rate of the alloy after the heat treatment became 0.089mm/y and Rp equal 4.13KΩ/cm2, These results made the new magnesium alloy a good candidate for use in temporary medical applications.

5

Rare-earth and trace elements of the lower Cambrian–Lower Cretaceous siliciclastic succession of NE Gondwana in Jordan : from provenance to metasomatism

Amireh Belal S., Saffarini Ghazi A., Amaireh Mazen N., Jarrar Chaleb H., Abed Abdulkader A.

Annales Societatis Geologorum Poloniae

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2022

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Vol. 92, No. 2

109--158

EN

The present bulk-rock geochemical study aims to answer some questions concerning the distribution and variability of trace elements (TEs) and rare earth elements (REEs) in the lower Cambrian–Lower Cretaceous sandstones and mudstones of NE Gondwana in Jordan. The study proved that the REE and the TE distribution patterns in both detrital and authigenic, light and heavy minerals are controlled principally by the source-rock provenance, followed by an interplay of many factors: chemical weathering, recycling, hydraulic sorting, locally low-temperature, hydrothermal metasomatism, depositional environment and redox conditions, and diagenesis. On the basis of specific trace elements, trace-element ratios, and petrographic proxies, the provenance is constrained to be mainly felsic-, rarely mafic granitoids of the Arabian-Nubian Shield, and less commonly, recycled Palaeozoic and Mesozoic siliciclastic strata. REEs are hosted mainly in zircon, Ti-bearing minerals, and partly in clay minerals. They were depleted by both chemical weathering and recycling; nevertheless, they were enriched by subsequent hydraulic sorting and low-temperature, hydrothermal metasomatism. Chemical weathering initially depleted zirconium. However, this was counteracted by subsequent enrichment through recycling, hydraulic sorting, and low-temperature, hydrothermal metasomatism. The fractionation of the other TEs, due to these sedimentological factors during the genesis of subarkosic arenites, quartz arenites and mudstones, is discussed and some conclusions are derived. The Eu negative anomaly was enhanced significantly by recycling and low-temperature, hydrothermal metasomatism. Scandium abundance increased with decreasing grain size from coarse sand to the mud fraction. The recorded REE and TE fractionation might also apply to siliciclastics in similar, geological environments.

6

Crystal Lattice Damage and Recovery of Rare-Earth implanted Wide Bandgap Oxides

Sarwar Mahwish, Ratajczak Renata, Ivanov Vitalii, Mishra Sushma, Turek Marcin, Wierzbicka Aleksandra, Woźniak Wojciech, Guziewicz Elżbieta

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no 5

147--154

EN

Rare earth (RE) elements are important for the optical tuning of wide bandgap oxides (WBO) such as β-Ga2O3 or ZnO, because β-Ga2O3:RE or ZnO:RE show narrow emission lines in the visible, ultra-violet and infra-red region. Ion implantation is an attractive method to introduce dopant into the crystal lattice with an extraordinary control of the dopant ion composition and location, but it creates the lattice damage, which may render the dopant optically inactive. In this research work, we investigate the post-implantation crystal lattice damage of two matrices of wide-bandgap oxides, β-Ga2O3 and ZnO, implanted with rare-earth (RE) to a fluence of 5 x 10^14, 1 x 10^15 and 3 x 10^15 atoms/cm^2, and post-growth annealed in Ar and O2 atmosphere, respectively. The effect of implantation and annealing on both crystal lattices was investigated by channeling Rutherford backscattering spectrometry (RBS/C) technique. The level of crystal lattice damage caused by implantation with the same RE fluences in the case of β-Ga2O3 seems to be higher than in the case of ZnO. Low temperature photoluminescence was used to investigate the optical activation of RE in both matrices after performed annealing.

7

Application of chromatographic plate theory on the weathered crust elution-deposited rare earth ore with carboxylate

Zhang Zhenyue, Wang Guangshuai, Li Chunhua, Chi Ruan, Long Fei, Chen Zhuo, Chi Xiao Wang, Liu Defeng

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 4

48--62

EN

To improve the leaching process of rare earth and reduce the impurities in the leachate, the carboxylate ammonium, such as ammonium acetate, ammonium citrate and ammonium tartrate, were selected as lixiviant to compare the effects of concentration, flow rate, pH and temperature on leaching mass process of rare earth and aluminum. Meanwhile, the leaching behaviors of rare earth and aluminum leached by three kinds of carboxylate ammonium were analyzed by chromatographic plate theory. The relationship between the flow rate and height equivalent (HETP) could fit well with the Van Deemter equation and there was an optimal flow rate (uopt) for the leaching of the rare earth and aluminum. Besides, the conditions of carboxylate ammonium lixiviant were optimized. The optimum concentrations of ammonium acetate, ammonium tartrate and ammonium citrate were 15 g/L, 25 g/L and 5 g/L respectively, the leaching flow rate was 0.50 mL/min, the pH value was approximatively 7.00 and the leaching temperature was 293 K to 303 K. At these conditions, the mass transfer efficiencies of three ammonium carboxylates for rare earth and aluminum was in the order of ammonium acetate > ammonium tartrate > ammonium citrate. Moreover, the ammonium acetate could commendably inhibit aluminum ions entering the lixivium.

8

An Overview of Rare Earth Ores Beneficiation in Vietnam

Nhu Thi Kim Dung, Pham Van Luan, Vu Thi Chinh, Tran Van Duoc

Inżynieria Mineralna

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2021

|

no. 2

227--236

EN

Rare earth metals are used in electricity, electronics, nuclear, optics, space, metallurgy, superconducting and super magnetic materials, glass and ceramics, and agriculture. Some rare earth elements are added to fertilizers for crops and some trials for animal feed. Rare earth elements, except for radioactive promethium, are relatively abundant in the earth's crust. Vietnam has a tremendous rare earth potential, distributed mainly in the Northwest, including Nam Xe, Dong Pao, Muong Hum, and Yen Bai. There are many research projects on rare earth ores of different types globally, but the focus is mainly on the essential minerals, including monazite, xenotime, and bastnaesite. This report summarizes research data on rare earth ore intending to produce a general assessment of rare earth ore and its beneficiation technology in Vietnam.

9

Process mineralogy of Bayan Obo rare earth ore by MLA

Xu Caili, Chi Ru’an, Zhang Yantu, Zhong Chengbin, Ruan Yaoyang, Lyu Renliang, Zhou Fang

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 4

737--745

EN

The maximum recovery of rare earth resource from the Bayan Obo ore deposit is a difficult task, especially without the sufficient data of mineralogy. In this paper the mineralogy of Bayan Obo ore deposit by comprehensively research with the application of mineral liberation analyzer (MLA) is reported. The MLA was applied to quantitatively analyze the complicated element/mineral compositions, the REE occurrence, the size distribution and the degree of liberation of the Bayan Obo ore. Mineralogical analysis of the rare earth ore has shown that REEs are present mainly as bastnaesite and monazite-(Ce) to a small extent as parisite-(Ce). 5.85% of the REEs, 34.99% of iron and 0.12% of niobium occur in the ore sample. There are 76.99% of iron occurred in hematite and the remaining iron is mainly distributed in magnetite and goethite. The degree of liberation of bastnaesite and monazite(Ce) was 79.65% and 75.67% respectively when the grinding fineness was 83.57% passing 75 μm sieves. Un-liberated or partly liberated rare earth minerals are associated closely mainly with other rare earth minerals and gangues. These theoretical data could be employed to further comprehensively utilize the rare earth ore.

10

Study on Addition of Surfactants Agents to Improve the Behavior of High Water Content Sediment for Rare Earth Mining in Deep Sea

Sasaoka Takashi, Hamanaka Akihiro, Funatsu Takahiro, Shimada Hideki, Takahashi Keisuke

Inżynieria Mineralna

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2020

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no. 1, vol. 2

183--188

EN

Importance of rare mineral metal resources is increasing currently. Therefore, the rare earth elements rich mud which exist on the deep-sea floor has the potential to be developed to fulfill their demand. As one of the effective mining method, a suction mining method is expected to apply to seabed mining. The seabed sediment containing rare earth element shows the very high water content, more than 100%. And the sediment movement during the suction is greatly affected by the water content (WC) and liquid limit (WL) of the material. Therefore, it is important to modify the liquid limit by adding a chemical agent to control the behavior of sediment. We selected eight different surfactants which can be divided into three types. They are dispersant type, water retention type, and thickener type. We carried out a liquid limit test and viscosity measurement of the sediment mixed with the agents. It is found that the water-absorbing polymer and the hydroxyethyl cellulose increase the liquid limit and viscosity. Whereas, the alkyl ammonium salt surfactant and the alkyl ammonium salt, alkyl aryl sulfonate blend decrease the liquid limit and viscosity. It is possible to control sediment behavior by adding suitable surfactants.

PL

Złoża metali rzadkich są bardzo ważne a ich istotność wzrasta w ostatnich latach. Zatem, dno morskie, które zawiera duże ilości tego typu pierwiastków posiada potencjał do zaspokojenia potrzeb w tym zakresie. Jako jedną z efektywnych metod górniczych w tym aspekcie należy traktować ssanie. Osad denny z dna morskiego, który zawiera pierwiastki ziem rzadkich wykazuje bardzo dużą zawartość wody. Ruch osadu podczas ssania jest uzależniony w dużym stopniu od zawartości wody (WC) oraz krytycznego limitu cieczy (WL) materiału. Zatem, ważnym jest aby zmodyfikować limit cieczy poprzez dodatek odczynnika chemicznego w celu kontrolowania zachowania się osadu. Wybrano osiem różnych odczynników powierzchniowych, które mogą być podzielona na trzy typy. Są to odczynniki typu dyspergującego, typu retencji wody oraz typu zagęszczającego. Przeprowadzono test limitu cieczy i pomiaru lepkości osadu wymieszanego z odczynnikami. Stwierdzono, że polimer absorbujący wodę oraz hydroksyetyloceluloza zwiększają limit cieczy oraz lepkość. Z kolei, sól amoniowo-alkilowa oraz blenda alkiloarylosulfonianowa zmniejszają te wielkości. Możliwa jest kontrola zachowania się osadu poprzez dodatek odpowiednich odczynników powierzchniowych.

11

Effect of Fe Content on the Mechanical Properties and Thermal Conductivity of the Al-RE Alloys

Yoo Hyo-Sang, Kim Yong-Ho, Son Hyeon-Taek

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 3

1029--1033

EN

In this study, we investigated the effect of Fe addition (0, 0.25, 0.50 and 0.75 wt.%) on the microstructure, mechanical properties and electrical conductivity of as-cast and as-extruded Al-RE alloys. As the Fe element increased by 0 and 0.75wt.%, the phase fraction increased to 5.05, 5.76, 7.14 and 7.38 %. The increased intermetallic compound increased the driving force for recrystallization and grain refinement. The electrical conductivity of Al-1.0 wt.%RE alloy with Fe addition decreased to 60.29, 60.15, 59.58 and 59.13 % IACS. With an increase in the Fe content from 0 to 0.75 wt.% the ultimate tensile strength (UTS) of the alloy increased from 74.3 to 77.5 MPa. As the mechanical properties increase compared to the reduction of the electrical conductivity due to Fe element addition, it is considered to be suitable for fields requiring high electrical conductivity and strength.

12

Adsorption of lanthanum(III) and yttrium(III) on kaolinite: kinetics and adsorption isotherms

Zhou Fang, Feng Jian, Xie Xiong, Wu Baihong, Liu Qi, Wu Xiaoyan, Chi Ruan

Physicochemical Problems of Mineral Processing

|

2019

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Vol. 55, iss. 4

928--939

EN

Experimental investigations were carried out using kaolinite to adsorb two rare earth ions, lanthanum ion (La3+) and yttrium ion (Y3+), which will provide some useful information and new insights on the mineralization process and fractionation phenomenon of weathered crust elution-deposited rare earth ores. The results showed that the equilibrium adsorption capacity of Y3+ is greater than La3+ under the same experimental conditions. The adsorption of rare earth ions presents strongly temperature dependent indicating an endothermic adsorption process. The pseudo-first-order kinetic model and the pseudo-second-order kinetic model were applied to discuss the adsorption kinetics. It was found that the adsorption rate of rare earth follows the pseudo-second-order kinetic model among the adsorption temperature range. Furthermore, the adsorption process of rare earth ions on kaolinite followed the Langmuir isotherm model confirmed by the correlation of experimental equilibrium data to standard isotherm model, Langmuir and Freundlich isotherms. The activation energies for the adsorption of La3+ and Y3+ on kaolinite are 28.1903 kJ/mol and 25.4190 kJ/mol, respectively. All kaolinite before and after adsorption were characterized by XRD and SEM-EDX to understand the adsorption mechanism. The obtained results suggested that the adsorption of La3+ and Y3+ on kaolinite is an endothermic and chemisorption process.

13

Tlenkowe przewodniki superjonowe bivox domieszkowane pierwiastkami ziem rzadkich (La, Pr).

Paściak G., Chmielowiec J., Bujło P.

Prace Naukowe Instytutu Podstaw Elektrotechniki i Elektrotechnologii Politechniki Wrocławskiej. Konferencje

|

2006

|

Vol. 44, nr 18

122-127

PL

Materiały z rodziny B1VOX (ang. Bismuth Vanadium Oxide) charakteryzują się dużą przewodnością jonową w stosunkowo niskich temperaturach i dlatego są potencjalnymi kandydatami na materiał elektrolityczny w urządzeniach elektrochemicznych takich jak: ogniwa paliwowe IT-SOFC (Intermediate Temperaturę Solid Oxide Fuel Celi) oraz pompy, separatory i czujniki tlenu. Stosując dodatki podstawiające atomy Bi i V w strukturze Bi4V2O11 można -stabilizować poszczególne odmiany polimorficzne materiału, a także modyfikować jego przewodność. Publikacja przedstawia badania autorów dotyczące wpływu dodatków pierwiastków ziem rzadkich -La i Pr na stabilność termodynamiczną i przewodność elektrolitu Bi4V2O11.

EN

BIVOX (Bismuth Vanadium Oxide) family materials are characterized by high ionic conductivity at relatively low temperature that's why are potential candidates for electrolytic materials used in electrochemical devices as: IT-SOFC (Intermediate Temperature Solid Oxide, Fuel Cell), oxygen pumps, separators and sensors. Applying additives, which substitute Bi and V atoms in the Bi4V2O11structure, one can stabilize individual polymorphic modifications as well as modify theirs conductivity. Present paper presents description of research concerning investigations of the influence of additives - rare-earth elements as La and Pr - on thermodynamic stability and ionic conductivity of Bi4 V2 O11 electrolyte.

14

Soil contamination I a rural site used for rare earth industry by-product disposal

Briquet C., Lauria D.

Prace Naukowe GIG. Górnictwo i Środowisko / Główny Instytut Górnictwa

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2004

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nr 1

44-45

15

Natural radionuclides in rare earth industry and their environmental effects

Hou X., Feng W.

Prace Naukowe GIG. Górnictwo i Środowisko / Główny Instytut Górnictwa

|

2004

|

nr 1

31-31

16

Magnetic and hyperfine interaction in YbFe4Al8 compound

Gaczyński P., Drulis H.

Nukleonika

|

2004

|

Vol. 49,suppl.3

33-36

EN

57Fe Mössbauer spectra of YbFe4Al8 of the tetragonal ThMn12 structure have been investigated. Mössbauer measurements at the lowest temperatures yield information on the iron population in three crystallographic sites 8f, 8j and 8i available for Fe atoms. The obtained results indicate on the coexistence of magnetically ordered and paramagnetic-like Fe moments within antiferromagnetic phase of YbFe4Al8. The MS measurements show that the onset of short range antiferromagnetic interaction in the Fe sublattice takes place at 220 K.

17

Structural and Mössbauer effect studies of Dy(Fe0.4Co0.6-x Alx)2 intermetallics

Stoch P., Pszczoła J., Suwalski J., Pańta A.

Nukleonika

|

2003

|

Vol. 48,suppl.1

75-77

EN

The magnetic hyperfine fields observed at the 57Fe nuclei (77 K) in the Dy(Mn1-xFex)2 and Dy(Fe1-xCox)2 intermetallics form a Slater-Pauling curve. In order to study the effect of cobalt atoms on crystal structure and hyperfine interactions, the new Co/Al substituted series Dy(Fe0.4Co0.6-xAlx)2 was prepared and data of X-ray powder analysis are presented (300 K). From the 57Fe Mössbauer measurements at 77 K the hyperfine parameters were obtained. The magnetic hyperfine fields form a branch of the Slater-Pauling curve.

18

57Fe Mössbauer effect studies of ErFe11Ti and ErFe11TiH compounds

Gaczyński P., Tereshina I., Rusakov V., Nikitin S., Drulis H.

Nukleonika

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2003

|

Vol. 48,suppl.1

25-29

EN

Ferromagnetic compounds ErFe11TiHx (x = 0, 1) have been investigated by 57Fe Mössbauer spectroscopy in the temperature range 20–300 K. Mössbauer spectra were analyzed in terms of a model which takes into account the local environment of Fe atoms on three crystallographic sites (8f, 8j and 8i) and an influence of the random distribution of titanium on the 8i site. The 14 sextets with different intensities have been considered. The temperature dependencies of hyperfine interaction parameters and subspectra contributions were derived from experimental spectra. The hyperfine fields and the isomer shift increasing upon hydrogenation are discussed in terms of the hydrogen-induced Wigner-Seitz unit cell expansion and the s-electrons transfer from Fe atoms to the adjacent hydrogen atoms.

19

Crystal Structure of the New Ternary Th2Ni17-Type Related Compounds in the R-Mn-Al Systems (R=Gd, Tb, Dy, Ho, Er)

Kotur B, Palasyuk A.M.

Polish Journal of Chemistry

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2001

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Vol. 75, nr 5

633--637

EN

New hexagonal ternary phases R2-yMnzMnxAl17-x have been obtained in the Mn-rich regions of the R-Mn-Al (R = Gd, Tb, Dy, Ho, Er) systems: Gd2-yMnxAl17-x (0_y_0.15, 13.0 _x_ 15.1); Tb2-yMnxAl17-x (0_ y_0.23, 13.2_x_15.2); Dy2-yMnxAl17-x (0_y<~0.2, 11.9_x _14.6); Ho2-yMnxAl17-x (0_y<~0.2, 11.5_x_14.2) and Er2-yMnzMnxAl17-x (0_y_0.27, 0_ z_0.54, 11.3_x_14.1). Th2Ni17-type of structure occurs in alloys with the content of R = 10.5 at.% (ideal R2X17 stoichiometry). When R < 10.5 at.%, two ways of structure constitution are possible: i) formation of the Th2Ni17- type structure with defective 2(b) atomic position (solid solution of subtraction); ii) formation of the Th2Ni17-related type structure with the substitution of part of R atoms by the Mn-Mn pairs (solid solution of multiple substitution).

20

Nowe kierunki w technologii borowania stali.

Przybyłowicz K.

Inżynieria Materiałowa

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2000

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R. XXI, nr 6

403-406

PL

Pomimo stosowania borowania już od ponad stu lat ciągle są wprowadzane liczne modyfikacje. Jedną z nich jest stopowanie borkowych warstw metalami rzadkimi (RE), Ni, S i N. RE obniżają temperaturę procesu i zawartość borka FeB oraz poprawiają własności warstw (zwiększają ciągliwość i odporność na korozję, zmęczenie i zużycie ścierne). RE - borowanie było stosowane do stali szybkotnących, narzędziowych, łopatek turbin i kompleksowych powłok (z Al, V, N, C). Wiele eksperymentów wykazało pozytywny wpływ nikloborowania (podobnie jak w przypadku RE-borowania). Siarkoborowanie obniża współczynnik tarcia i zapobiega zacieraniu. Inną modyfikacją jest kombinacja borowania ze zgniotem lub odkształceniem nadplastycznym, które sprzyja przyspieszeniu procesu i poprawia ciągliwość warstw. Interesującą metodą jest borowanie z past wspomagane wyładowaniem jarzeniowym. Obróbka taka może być przeprowadzana przy niskiej temperaturze (500 stopni Celsjusza) i warstwa złożona z Fe2B jest mniej krucha i bardziej odporna na korozję, i zużycie ścierne. Bardzo obiecujące jest borowanie po plazmowym lub ogniowym natrysku niklem, stopem Ni-Cr, stalą nierdzewną. Przede wszystkim poprawia żaroodporność, odporność na korozję i zużycie ścierne oraz zwiększa szybkość nasycania. Zostały także opracowane nowe składy borujących ośrodków. Skład borowanych stali, metoda i parametry borowania oraz obróbka cieplna powinny być wybierane w zależności od wymaganych własności i warunków pracy elementów.

EN

In spite of over 100 years application of boronizing process numerous modifications are constantly introduced. One of it is alloying the borided coatings in rare earths (RE), Ni, S and N. RE decrease the temperature of the process and content of FeB phase and improve properties of the coating (raise toughness, corrosion, fatigue and wear resistance). RE-boronizing has been applied to HSS, tool steels, turbine blades and complex coatings (with Al, V, N, C). A lot of experiments show profitable effect of Ni - boronizing (similar as in the case of RE - boronizing). S - boronizing lowers the friction coefficient and prevents seizure. Another modification is combination of boronizing with cold work or superplastic deformation which affects in accelerating of the process and improving toughness of the coatings. Interesting method is paste - boronizing in glow - discharge chamber. The treatment may be carried out at low temperature (500 degrees centigrade) and coating consisting of Fe2B is less brittle and more wear- and corrosion-resistant. Very prospective is boronizing following the plasma or flame spraying of Ni, Ni-Cr alloy, stainless steel. First of all improves the corrosion, heat and wear resistance, increases rate of the process. New compositions of boronizing media have also been worked out. The composition of boronized steels, saturation method and heat treatment should be chosen according to required properties and condition of work of elements.