Electrospark alloying of titanium and its alloys: The physical, technological, and practical aspects. Part I. The peculiarities of the mass transfer and the structural and phase transformations in the surface layers and their wear and heat resistance

Mikhailov, V. V.; Gitlevich, A. E.; Verkhoturov, A. D.; Mikhailyuk, A. I.; Belyakov, A. V.; Konevtsov, L. A.

doi:10.3103/s1068375513050074

Cited by 35 publications

(26 citation statements)

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“…Такое увеличение привеса катода можно объяснить участием диэлектрического порошка WC в инициировании разрядов. Присутствие частиц WC в межэлектродном промежутке способствует лучшему прерыванию электрического контакта в момент прохождения импульса, что повышает вероятность развития разрядов [13]. Неравномерное увеличение привеса подложки при увеличении содержания порошка в смеси гранул выше 4.1 об.% может быть вызвано охрупчиванием покрытия из-за дефицита связующего и как следствие вызывать повышенную электрическую эрозию катода.…”

Section: результаты и обсуждениеunclassified

“…[8 -12]. Технология ЭИЛ основана на явлении электрической эрозии и переноса материала анода на поверхность катода-детали при протекании импульсных (искровых) разрядов в газовой среде [13]. Преимуществом ЭИЛ является простота и доступность оборудования, высокая адгезия покрытий за счет металлургического сплавления с материалом подложки.…”

Section: Introductionunclassified

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Electrospark deposition of tungsten carbide powder on titanium alloy Ti6Al4V

2021

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Titanium alloys are attracting the attention of researchers and engineers because of their unique combination of high specific strength, corrosion resistance and biocompatibility, but they are characterized by high wear. Therefore, the study of new methods for making protective coatings on titanium alloys is relevant. A mixture of titanium granules with tungsten carbide powder was used to prepare coatings on the titanium alloy Ti6Al4V by the method of electrospark granules deposition. Three mixtures of granules with a tungsten carbide content of 2.1, 4.1 and 6.0 vol.% were prepared. According to the data of X-ray analysis, it was found that the following phases were observed in the composition of the coatings: WC, W 2 C, W, αTi and β-(W, Ti)C 1−x . Carbides W 2 C, (W, Ti)C 1−x and metallic tungsten were formed as a result of the decarburization of WC upon its interaction with molten titanium under the conditions of an electric discharge. Large inclusions of tungsten carbide surrounded by a metallic Ti-W-C binder were observed in the microstructure of the coatings. According to the data of energy dispersive analysis, the concentrations of tungsten and carbon decreased when scanning from the surface layers of the coating to the substrate. The average values of the microhardness of the coatings increased from 7.9 to 9.2 GPa with an increase in the concentration of WC powder in the mixture of granules. The average values of the friction coefficients of the coatings were in the range of 0.33 -0.48, which is 35 ± 3 % lower than that of the Ti6Al4V alloy. Tests for wear in the dry friction mode at loads of 25 and 70 N showed that the wear rate of the coatings ranged from 0.38 ×10 −5 to 1.68 ×10 −5 mm 3 / Nm. The best wear resistance under both loads was demonstrated by the coatings deposited with the addition of 4.1 vol.% WC, which make it possible to increase the wear resistance of the Ti6Al4V alloy up to 18 times. Thus, the prospect of electrospark deposition of cermet coatings with enhanced mechanical properties on a titanium alloy using tungsten carbide powder mixed with titanium granules is shown.

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Section: результаты и обсуждениеunclassified

Section: Introductionunclassified

Electrospark deposition of tungsten carbide powder on titanium alloy Ti6Al4V

2021

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“…В процессе эксплуатации тестоделительной машины изнашиваются рабочие поверхности деталей как всасывающего, так и делительного механизмов [18][19][20][21]. Так как торцевая часть всасывающей камеры со стороны делительного механизма закрыта остатками теста, то на падение вакуума будет влиять увеличение зазоров в соединениях «всасывающий поршень -вертикальная часть камеры», «отрезной нож -вертикальная часть камеры», «отрезной ножверхняя часть камеры всасывания», «поршень -дно камеры» и «поршеньотрезной нож».…”

Section: Introductionunclassified

The Assessment of the Limit State of the Vacuum Piston Type Dough Divider by Oil Consumption

Величко

Martynova

Иванов

2020

Engineering Technologies and Systems

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Introduction. Agriculture includes one of the branches of raw material processing, the final product of which is bread making. At the same time, the most complex operation in the technological chain of bread making is the division of the finished dough into billets of the same mass. This operation is performed by vacuum-piston type dough dividers. Under operating conditions, the service life of dividers is 30-40% lower than the manufacturer’s stated. In the technical documentation there is not point of the limit state of dividers, so they continued to be used with high costs of technological materials that determine the cost of the finished product. The purpose of the work is to determine the criterion for evaluating the performance of dough dividers and the limit value of the criterion. Materials and Methods. Evaluation of the technical condition of vacuum piston type dough dividers was based on the edible oil consumption of food line WP 32 (manufacturer AIMOL). To measure the mass of the consumed oil and the mass of the dough pieces, scales were used with an accuracy of ±0.1 g and ±1 g, respectively. Results. Based on the results of the analysis of the operation principle of dough dividers, the criterion of efficiency is called the oil consumption, which is responsible for the accuracy of weighing the dough through creating a vacuum in the suction chamber when filling gaps in the coupling of parts. When evaluating the technical condition of machines by manufacturing 300 test pieces configured for a mass of 500 g the maximum oil consumption is obtained equal to 218 g. According to the maximum oil consumption, the allowed oil consumption is determined to be 109 g. Discussion and Conclusion. It is established that at bakery enterprises, about 30% of used dough dividers have an over-extreme limit state and the accuracy in weighing the dough cannot be restored by increasing the oil consumption. However, starting from the oil consumption above the allowed value of 109 g, the machines need major repairs. The obtained values of the limit and allowed state of dough dividers are widely used in bakery enterprises to assess their technical condition.

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“…Vacuum electro-spark alloying (VESA) is another promising modification of the process, but has some caveats of its own. On the one hand, coatings deposited in noble gas environments (He, Ar) and in vacuums have lower defect concentrations in comparison with ones deposited in air; on the other hand, pressure decrement leads to the decrease in the coating growth rate [14]. Research [15] shows that coatings made in vacuums are more chemically homogeneous and have higher corrosion resistance.…”

Section: Introductionmentioning

confidence: 99%

Two-Layer Nanocomposite TiC-Based Coatings Produced by a Combination of Pulsed Cathodic Arc Evaporation and Vacuum Electro-Spark Alloying

Kiryukhantsev-Korneev

Сытченко

Sheveyko

et al. 2020

Materials

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A novel two-stage technology combining vacuum electro-spark alloying (VESA) and pulsed cathodic arc evaporation (PCAE) was approbated for the deposition of TiC-based coatings in inert (Ar) and reactive (C2H4) atmospheres. The deposition was carried out using a TiC-NiCr-Eu2O3 electrode and 5140 steel substrates. Structural, elemental, and phase compositions of the deposited coatings were investigated by scanning electron microscopy, energy-dispersive spectrometry, and X-ray diffraction. The mechanical properties of the coatings were measured by nanoindentation using a 4 mN load. The tribological properties of the coatings were measured using the pin-on-disc setup in air and in distilled water at a 5 N load. The experimental data suggest that VESA coatings are characterized by surface defects, a hardness of 12.2 GPa, and a friction coefficient of 0.4. To ensure good adhesion between the VESA coating and the upper layer containing diamond-like carbon (DLC), an intermediate layer was deposited by PCAE in the Ar atmosphere. The intermediate layer had a hardness of up to 31 GPa. The upper layer of the coating ensured a low and stable friction coefficient of 0.2 and high wear resistance due to the formation of an sp2–sp3 bound carbon phase. Multilayer TiC-based coating with the upper DLC layer, in addition to high tribological properties, was characterized by the lowest corrosion current density (12 μA/cm2).

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Electrospark alloying of titanium and its alloys: The physical, technological, and practical aspects. Part I. The peculiarities of the mass transfer and the structural and phase transformations in the surface layers and their wear and heat resistance

Cited by 35 publications

References 0 publications

Electrospark deposition of tungsten carbide powder on titanium alloy Ti6Al4V

Electrospark deposition of tungsten carbide powder on titanium alloy Ti6Al4V

The Assessment of the Limit State of the Vacuum Piston Type Dough Divider by Oil Consumption

Two-Layer Nanocomposite TiC-Based Coatings Produced by a Combination of Pulsed Cathodic Arc Evaporation and Vacuum Electro-Spark Alloying

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