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<article article-type="research-article" dtd-version="1.3" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:lang="ru"><front><journal-meta><journal-id journal-id-type="publisher-id">vguit</journal-id><journal-title-group><journal-title xml:lang="ru">Вестник Воронежского государственного университета инженерных технологий</journal-title><trans-title-group xml:lang="en"><trans-title>Proceedings of the Voronezh State University of Engineering Technologies</trans-title></trans-title-group></journal-title-group><issn pub-type="ppub">2226-910X</issn><issn pub-type="epub">2310-1202</issn><publisher><publisher-name>VSUET</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.20914/2310-1202-2021-4-261-268</article-id><article-id custom-type="elpub" pub-id-type="custom">vguit-2866</article-id><article-categories><subj-group subj-group-type="heading"><subject>Research Article</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="ru"><subject>Химическая технология</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="en"><subject>Fundamental and Applied chemistry, chemical technology</subject></subj-group></article-categories><title-group><article-title>Исследование критериев качества двухфазных композитных покрытий на основе железа, формируемых методом плазменного напыления</article-title><trans-title-group xml:lang="en"><trans-title>Study of quality criteria for two-phase iron-based composite coatings formed by plasma spraying</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author" corresp="yes"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0002-1844-5011</contrib-id><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Жачкин</surname><given-names>С. Ю.</given-names></name><name name-style="western" xml:lang="en"><surname>Zhachkin</surname><given-names>S. Y.</given-names></name></name-alternatives><bio xml:lang="ru"><p>д.т.н., профессор, кафедра автоматизированного оборудования машиностроительного производства, Московский просп., 14, г. Воронеж, 394000, Россия</p></bio><bio xml:lang="en"><p>Dr. Sci. (Engin.), professor, automated equipment of machine-building production department, Moskovsky Ave., 14, Voronezh, 394000, Russia</p></bio><email xlink:type="simple">zhach@list.ru</email><xref ref-type="aff" rid="aff-1"/></contrib><contrib contrib-type="author" corresp="yes"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0002-7739-5587</contrib-id><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Трифонов</surname><given-names>Г. И.</given-names></name><name name-style="western" xml:lang="en"><surname>Trifonov</surname><given-names>G. I.</given-names></name></name-alternatives><bio xml:lang="ru"><p>младший научный сотрудник, НИЦ (ППО и УА ВВС), ул. Старых Большевиков, 54А, г. Воронеж, 394064, Россия</p></bio><bio xml:lang="en"><p>junior researcher, research center, 54A Starye Bolshevikov str. Voronezh, 394064, Russia</p></bio><email xlink:type="simple">trifonov_gi@yandex.ru</email><xref ref-type="aff" rid="aff-2"/></contrib><contrib contrib-type="author" corresp="yes"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0002-9907-9649</contrib-id><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Егорова</surname><given-names>Г. Н.</given-names></name><name name-style="western" xml:lang="en"><surname>Egorova</surname><given-names>G. N.</given-names></name></name-alternatives><bio xml:lang="ru"><p>к.п.н., доцент, кафедра машин и аппаратов химических производств, пр-т Революции, 19, г. Воронеж, 394036, Россия</p></bio><bio xml:lang="en"><p>Cand. Sci. (Ped.), associate professor, machines and apparatuses of chemical production department, Revolution Av., 19 Voronezh, 394036, Russia</p></bio><email xlink:type="simple">egorovahp@gmail.com</email><xref ref-type="aff" rid="aff-3"/></contrib><contrib contrib-type="author" corresp="yes"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0002-7480-0487</contrib-id><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Белых</surname><given-names>А. Г.</given-names></name><name name-style="western" xml:lang="en"><surname>Belyh</surname><given-names>A. G.</given-names></name></name-alternatives><bio xml:lang="ru"><p>к.т.н., старший научный сотрудник, НИЦ (ППО и УА ВВС), ул. Старых Большевиков, 54А, г. Воронеж, 394064, Россия</p></bio><bio xml:lang="en"><p>Cand. Sci. (Engin.), senior researcher, research center, 54A Starye Bolshevikov str. Voronezh, 394064, Russia</p></bio><email xlink:type="simple">grishakip@yandex.ru</email><xref ref-type="aff" rid="aff-4"/></contrib></contrib-group><aff-alternatives id="aff-1"><aff xml:lang="ru"><institution>Воронежский государственный технический университет</institution><country>Россия</country></aff><aff xml:lang="en"><institution>Voronezh State Technical University</institution><country>Russian Federation</country></aff></aff-alternatives><aff-alternatives id="aff-2"><aff xml:lang="ru"><institution>Военно-воздушная академия имени профессора Н.Е. Жуковского и Ю.А. Гагарина</institution><country>Russian Federation</country></aff><aff xml:lang="en"><institution>The Air Force Academy named after Professor N.E. Zhukovsky and Yu.A. Gagarin</institution><country>Russian Federation</country></aff></aff-alternatives><aff-alternatives id="aff-3"><aff xml:lang="ru"><institution>Воронежский государственный университет инженерных технологий</institution><country>Russian Federation</country></aff><aff xml:lang="en"><institution>Voronezh State University of Engineering Technologies</institution><country>Russian Federation</country></aff></aff-alternatives><aff-alternatives id="aff-4"><aff xml:lang="ru"><institution>Военно-воздушная академия имени профессора Н.Е. Жуковского и Ю.А. Гагарина</institution><country>Russian Federation</country></aff><aff xml:lang="en"><institution>The Air Force Academy named after Professor N.E. Zhukovsky and Yu.A. Gagarin</institution><country>Russian Federation</country></aff></aff-alternatives><pub-date pub-type="collection"><year>2021</year></pub-date><pub-date pub-type="epub"><day>24</day><month>05</month><year>2025</year></pub-date><volume>83</volume><issue>4</issue><fpage>261</fpage><lpage>268</lpage><permissions><copyright-statement>Copyright &amp;#x00A9; Жачкин С.Ю., Трифонов Г.И., Егорова Г.Н., Белых А.Г., 2022</copyright-statement><copyright-year>2022</copyright-year><copyright-holder xml:lang="ru">Жачкин С.Ю., Трифонов Г.И., Егорова Г.Н., Белых А.Г.</copyright-holder><copyright-holder xml:lang="en">Zhachkin S.Y., Trifonov G.I., Egorova G.N., Belyh A.G.</copyright-holder><license xml:lang="ru" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>Данная работа распространяется под лицензией Creative Commons Attribution 4.0.</license-p></license><license xml:lang="en" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>This work is licensed under a Creative Commons Attribution 4.0 License.</license-p></license></permissions><self-uri xlink:href="https://www.vestnik-vsuet.ru/vguit/article/view/2866">https://www.vestnik-vsuet.ru/vguit/article/view/2866</self-uri><abstract><p>Все большую актуальность в области ремонта и восстановления машин и механизмов приобретают газотермические методы нанесения функциональных покрытий на рабочие поверхности деталей машинных узлов. Назначение газотермических методов нанесения покрытий заключается в обеспечении и получении специальных физико-механических свойств поверхности детали, а также в восстановлении изношенных узлов и механизмов после их долгосрочной и интенсивной эксплуатации. Эффективным способом газотермической обработки поверхности детали является плазменное напыление композитных покрытий. В данной работе проведено исследование по вопросу оптимального подбора материала для плазменного напыления детали с учетом её эксплуатационных особенностей и видов износа рабочих поверхностей. В частности, проанализированы условия эксплуатации шнека транспортирующего конвейера. Рассмотрены технологические особенности нанесения композитных материалов технологией плазменного напыления. Произведен теоретический подбор двухфазного дисперсно-наполненного композита для нанесения на рабочие поверхности шнека с целью его восстановления и упрочнения. Проведены исследования и анализ одного из главных показателей качества формируемого покрытия после плазменного напыления – величина образовывающихся остаточных напряжений (растяжения и сжатия). Беря за основу кинематические режимы и особенности геометрии рабочих поверхностей шнека, а также критерии формирования толщины напыляемого слоя, получены расчетные уравнения по определению остаточных напряжений, возникающих на винтовой и цилиндрической поверхностях шнека транспортирующего конвейера. Сделан вывод о том, что для достижения необходимых физико-механических свойств покрытия объемная доля наполнителя в матрице композитного порошка ПГ-СР4 должна находиться в диапазоне 20–25%. Следовательно, возможно применение на практике дисперсно-наполненного композита типа NiСrВSiFе с 20–25% упрочняющих частиц наполнителя ТiС с целью вос-становления деталей машин и механизмов.</p></abstract><trans-abstract xml:lang="en"><p>The increasing relevance in the field of repair and restoration of machines and mechanisms is acquiring gas-thermal methods of applying functional coatings to the working surfaces of parts of machine assemblies. The purpose of gas-thermal coating methods is to provide and obtain special physical and mechanical properties of the surface of the part, as well as to restore worn-out components and mechanisms after their long-term and intensive operation. Plasma spraying of composite coatings is an effective method of gas-thermal treatment of the surface of a part. In this paper, a study was conducted on the optimal selection of material for plasma spraying of a part, taking into account its operational features and types of wear of working surfaces. In particular, the operating conditions of the screw of the conveying conveyor are analyzed. The technological features of the application of composite materials by plasma spraying technology are considered. The theoretical selection of a two-phase dispersed-filled composite for application to the working surfaces of the screw in order to restore and harden it has been carried out. Studies and analysis of one of the main indicators of the quality of the formed coating after plasma spraying – the magnitude of the resulting residual stresses (stretching and compression) have been carried out. Taking as a basis the kinematic modes and geometry features of the working surfaces of the screw, as well as the criteria for the formation of the thickness of the sprayed layer, the calculation equations for determining the residual stresses arising on the screw and cylindrical surfaces of the screw of the conveying conveyor are obtained. It is concluded that in order to achieve the required physical and mechanical properties of the coating, the volume fraction of the filler in the matrix of the PG-SR4 composite powder should be in the range of 20–25%. Therefore, it is possible to use in practice a particulate-filled composite of the NiСrВSiFе type with 20–25% reinforcing TiC filler particles in order to restore parts of machines and mechanisms.</p></trans-abstract><kwd-group xml:lang="ru"><kwd>композитные материалы</kwd><kwd>плазменное напыление</kwd><kwd>покрытие</kwd><kwd>остаточные напряжения</kwd><kwd>качество покрытия</kwd><kwd>рабочие поверхности</kwd></kwd-group><kwd-group xml:lang="en"><kwd>composite materials</kwd><kwd>plasma spraying</kwd><kwd>coating</kwd><kwd>residual stresses</kwd><kwd>coating quality</kwd><kwd>work surfaces</kwd></kwd-group></article-meta></front><back><ref-list><title>References</title><ref id="cit1"><label>1</label><citation-alternatives><mixed-citation xml:lang="ru">Ильющенко А.Ф., Шевцов А.И., Оковитый В.А., Громыко Г.Ф. Процессы формирования газотермических покрытий и их моделирование. Минск: Беларус. Навука, 2011. 357 с.</mixed-citation><mixed-citation xml:lang="en">Ilyushchenko A.F., Shevtsov A.I., Okovity V.A., Gromyko G.F. Processes of formation of gas-thermal coatings and their modeling. Minsk, Belarus. Navuka, 2011. 357 p. (in Russian).</mixed-citation></citation-alternatives></ref><ref id="cit2"><label>2</label><citation-alternatives><mixed-citation xml:lang="ru">Кравченко И.Н., Корнеев В.М., Коломейченко А.А., Пупавцев И.Е. Эффективные технологические методы нанесения покрытий газопламенным напылением // Агроинженерия. 2015. №. 1 (65).</mixed-citation><mixed-citation xml:lang="en">Kravchenko I.N., Korneev V.M., Kolomeichenko A.A., Pupavtsev I.E. Efficient technological methods for applying coatings by flame spraying. Agroengineering. 2015. no. 1 (65). (in Russian).</mixed-citation></citation-alternatives></ref><ref id="cit3"><label>3</label><citation-alternatives><mixed-citation xml:lang="ru">Табаков В.П. Формирование износостойких ионно-плазменных покрытий режущего инструмента. М.: Машиностроение, 2008. 311 с.</mixed-citation><mixed-citation xml:lang="en">Tabakov V.P. Formation of wear-resistant ion-plasma coatings of cutting tools. Moscow, Mashinostroenie, 2008. 311 p. (in Russian).</mixed-citation></citation-alternatives></ref><ref id="cit4"><label>4</label><citation-alternatives><mixed-citation xml:lang="ru">Пузряков А.Ф. Теоретические основы технологии плазменного напыления. М.: Изд-во МГТУ им. Н.Е. Баумана, 2008. 360 с.</mixed-citation><mixed-citation xml:lang="en">Puzryakov A.F. Theoretical foundations of plasma spraying technology. Moscow, Publishing house of MSTU im. NOT. Bauman, 2008. 360 p. (in Russian).</mixed-citation></citation-alternatives></ref><ref id="cit5"><label>5</label><citation-alternatives><mixed-citation xml:lang="ru">Казаков Н. Защитные покрытия // Время. 2014. Т. 10. С. 20.</mixed-citation><mixed-citation xml:lang="en">Kazakov N. Protective coatings. Time. 2014. vol. 10. pp. 20. (in Russian).</mixed-citation></citation-alternatives></ref><ref id="cit6"><label>6</label><citation-alternatives><mixed-citation xml:lang="ru">Ловшенко Ф.Г., Ловшенко Г.Ф. Закономерности формирования гранулометрического состава и структуры механически легированных композиционных порошков для газотермических покрытий // Литьё и металлургия. 2014. №. 2 (75).</mixed-citation><mixed-citation xml:lang="en">Lovshenko F.G., Lovshenko G.F. Patterns of formation of granulometric composition and structure of mechanically alloyed composite powders for gas-thermal coatings. Casting and metallurgy. 2014. no. 2 (75). (in Russian).</mixed-citation></citation-alternatives></ref><ref id="cit7"><label>7</label><citation-alternatives><mixed-citation xml:lang="ru">Жачкин С.Ю., Пухов Е.В., Трифонов Г.И., Комаров Я.В. и др. Анализ износостойкости функционального покрытия в условиях абразивного изнашивания сложнопрофильной детали трения // Вестник воронежского государственного аграрного университета. 2019. Т.12. № 3. С. 32–40.</mixed-citation><mixed-citation xml:lang="en">Zhachkin S.Yu., Pukhov E.V., Trifonov G.I., Komarov Ya.V. et al. Analysis of the wear resistance of a functional coating under conditions of abrasive wear of a complex-profile friction part. Bulletin of the Voronezh State Agrarian University. 2019. vol.12. no. 3. pp. 32–40. (in Russian).</mixed-citation></citation-alternatives></ref><ref id="cit8"><label>8</label><citation-alternatives><mixed-citation xml:lang="ru">Fauchais P., Vardelle M., Vardelle A., Goutier S. What do we know, what are the current limitations of suspension plasma spraying? // Journal of Thermal Spray Technology. 2015. V. 24. №. 7. P. 1120-1129. doi: 10.1007/s11666-015-0286-3</mixed-citation><mixed-citation xml:lang="en">Fauchais P., Vardelle M., Vardelle A., Goutier S. What do we know, what are the current limitations of suspension plasma spraying? Journal of Thermal Spray Technology. 2015. vol. 24. no. 7. pp. 1120-1129. doi: 10.1007/s11666-015-0286-3</mixed-citation></citation-alternatives></ref><ref id="cit9"><label>9</label><citation-alternatives><mixed-citation xml:lang="ru">Fauchais P., Joulia A., Goutier S., Chazelas C. et al. Suspension and solution plasma spraying // Journal of Physics D: Applied Physics. 2013. V. 46. №. 22. P. 224015.</mixed-citation><mixed-citation xml:lang="en">Fauchais P., Joulia A., Goutier S., Chazelas C. et al. Suspension and solution plasma spraying. Journal of Physics D: Applied Physics. 2013. vol. 46. no. 22. pp. 224015.</mixed-citation></citation-alternatives></ref><ref id="cit10"><label>10</label><citation-alternatives><mixed-citation xml:lang="ru">Jabbari F., Jadidi M., Wuthrich R., Dolatabadi A. A numerical study of suspension injection in plasma-spraying process // Journal of Thermal Spray Technology. 2014. V. 23. №. 1-2. P. 3-13. doi: 10.1007/s11666-013-0030-9</mixed-citation><mixed-citation xml:lang="en">Jabbari F., Jadidi M., Wuthrich R., Dolatabadi A. A numerical study of suspension injection in plasma-spraying process. Journal of Thermal Spray Technology. 2014. vol. 23. no. 1-2. pp. 3-13. doi: 10.1007/s11666-013-0030-9</mixed-citation></citation-alternatives></ref><ref id="cit11"><label>11</label><citation-alternatives><mixed-citation xml:lang="ru">Fauchais P., Vardelle M., Goutier S. Latest researches advances of plasma spraying: From splat to coating formation // Journal of Thermal Spray Technology. 2016. V. 25. №. 8. P. 1534-1553. doi: 10.1007/s11666-016-0435-3</mixed-citation><mixed-citation xml:lang="en">Fauchais P., Vardelle M., Goutier S. Latest researches advances of plasma spraying: From splat to coating formation. Journal of Thermal Spray Technology. 2016. vol. 25. no. 8. pp. 1534-1553. doi: 10.1007/s11666-016-0435-3</mixed-citation></citation-alternatives></ref><ref id="cit12"><label>12</label><citation-alternatives><mixed-citation xml:lang="ru">Антибас И.Р., Дьяченко А.Г. Определение характеристик компонентов композитных материалов, предназначенных для производства деталей сельскохозяйственной техники // Advanced Engineering Research. 2018. Т. 17. №. 3. С. 60–69.</mixed-citation><mixed-citation xml:lang="en">Antibas I.R., Dyachenko A.G. Determination of the characteristics of the components of composite materials intended for the production of agricultural machinery parts. Advanced Engineering Research. 2018. vol. 17. no. 3. pp. 60–69. (in Russian).</mixed-citation></citation-alternatives></ref><ref id="cit13"><label>13</label><citation-alternatives><mixed-citation xml:lang="ru">Hospach A., Mauer G., Va?en R., St?ver D. Characteristics of ceramic coatings made by thin film low pressure plasma spraying (LPPS-TF) // Journal of thermal spray technology. 2012. V. 21. №. 3. P. 435-440. doi: 10.1007/s11666-012-9748-z</mixed-citation><mixed-citation xml:lang="en">Hospach A., Mauer G., Va?en R., St?ver D. Characteristics of ceramic coatings made by thin film low pressure plasma spraying (LPPS-TF). Journal of thermal spray technology. 2012. vol. 21. no. 3. pp. 435-440. doi: 10.1007/s11666-012-9748-z</mixed-citation></citation-alternatives></ref><ref id="cit14"><label>14</label><citation-alternatives><mixed-citation xml:lang="ru">Бобров Г.В., Ильин А.А. Нанесение неорганических покрытий (теория, технология, оборудование). М.: Интермет Инжиниринг, 2004. 624 с.</mixed-citation><mixed-citation xml:lang="en">Bobrov G.V., Ilyin A.A. Deposition of inorganic coatings (theory, technology, equipment). Moscow, Intermet Engineering, 2004. 624 p. (in Russian).</mixed-citation></citation-alternatives></ref><ref id="cit15"><label>15</label><citation-alternatives><mixed-citation xml:lang="ru">Trifonov G., Zhachkin S., Penkov N., Krasnova M. Estimation of a Heat Distribution in a Part Plasma Coating Process // DEStech Transactions on Environment, Energy and Earth Sciences. 2018.</mixed-citation><mixed-citation xml:lang="en">Trifonov G., Zhachkin S., Penkov N., Krasnova M. Estimation of a Heat Distribution in a Part Plasma Coating Process. DEStech Transactions on Environment, Energy and Earth Sciences. 2018.</mixed-citation></citation-alternatives></ref><ref id="cit16"><label>16</label><citation-alternatives><mixed-citation xml:lang="ru">Sharifullin S.N., Trifonov G.I., Vyachina I.N. Calculation of parameters of particles in a plasma jet and modeling of kinematic models of spraying of wear resistant material // Journal of Physics: Conf. Series. 2018. V. 1058. (012047). doi: 10.1088/1742-6596/1058/1/012047</mixed-citation><mixed-citation xml:lang="en">Sharifullin S.N., Trifonov G.I., Vyachina I.N. Calculation of parameters of particles in a plasma jet and modeling of kinematic models of spraying of wear resistant material. Journal of Physics: Conf. Series. 2018. vol. 1058. (012047). doi: 10.1088/1742-6596/1058/1/012047</mixed-citation></citation-alternatives></ref><ref id="cit17"><label>17</label><citation-alternatives><mixed-citation xml:lang="ru">Farrokhpanah A., Coyle T.W., Mostaghimi J. Numerical study of suspension plasma spraying // Journal of Thermal Spray Technology. 2017. V. 26. №. 1-2. P. 12-36. doi: 10.1007/s11666-016-0502-9</mixed-citation><mixed-citation xml:lang="en">Farrokhpanah A., Coyle T.W., Mostaghimi J. Numerical study of suspension plasma spraying. Journal of Thermal Spray Technology. 2017. vol. 26. no. 1-2. pp. 12-36. doi: 10.1007/s11666-016-0502-9</mixed-citation></citation-alternatives></ref><ref id="cit18"><label>18</label><citation-alternatives><mixed-citation xml:lang="ru">Буркин С.П., Шимов Г.В., Андрюкова Е.А. Остаточные напряжения в металлопродукции. Екатеринбург: Изд-во Урал. ун-та, 2015. 248 с.</mixed-citation><mixed-citation xml:lang="en">Burkin S.P., Shimov G.V., Andryukova E.A. Residual stresses in metal products. Yekaterinburg, Publishing House Ural. un-ta, 2015. 248 p. (in Russian).</mixed-citation></citation-alternatives></ref><ref id="cit19"><label>19</label><citation-alternatives><mixed-citation xml:lang="ru">Yang G.J., Li C.X., Hao S., Xing Y.Z. et al. Critical bonding temperature for the splat bonding formation during plasma spraying of ceramic materials // Surface and Coatings Technology. 2013. V. 235. P. 841-847. doi: 10.1016/j.surfcoat.2013.09.010</mixed-citation><mixed-citation xml:lang="en">Yang G.J., Li C.X., Hao S., Xing Y.Z. et al. Critical bonding temperature for the splat bonding formation during plasma spraying of ceramic materials. Surface and Coatings Technology. 2013. vol. 235. pp. 841-847. doi: 10.1016/j.surfcoat.2013.09.010</mixed-citation></citation-alternatives></ref><ref id="cit20"><label>20</label><citation-alternatives><mixed-citation xml:lang="ru">Mauer G., Schlegel N., Guignard A., Jarligo M.O. et al. Plasma spraying of ceramics with particular difficulties in processing // Journal of thermal spray technology. 2015. V. 24. №. 1-2. P. 30-37. doi: 10.1007/s11666-014-0149-3</mixed-citation><mixed-citation xml:lang="en">Mauer G., Schlegel N., Guignard A., Jarligo M.O. et al. Plasma spraying of ceramics with particular difficulties in processing. Journal of thermal spray technology. 2015. vol. 24. no. 1-2. pp. 30-37. doi: 10.1007/s11666-014-0149-3</mixed-citation></citation-alternatives></ref></ref-list><fn-group><fn fn-type="conflict"><p>The authors declare that there are no conflicts of interest present.</p></fn></fn-group></back></article>
