The Structure and Protective Properties of Complex Chromium, Ti-tanium, Aluminum Based Diffusion Coatings on U8A Steel

Тетяна Володимирівна Лоскутова

Abstract


 

Background. Modern materials work under stringent conditions of simultaneous action of high production speeds, high temperatures, aggressive environments, and therefore the materials they are made of must have an integrated protective properties: to combine wear resistance, high crack resistance, chemical stability at elevated           temperatures, high corrosion resistance. Despite the large number of known types of coatings and their methods of obtaining scientific aspects of creation of coatings with a wide range of protective properties is not sufficiently developed.

Objective. Study of phase and chemical compositions, structure and protective properties of coatings on U8A steel, obtained by combining of diffusion chromium plating with the subsequent titanium aluminizing.

Methods. The coating was applied on the surface of the U8A steel. On the first stage, the gas plating at a temperature of 1050 °C for 4 hours was carried out. On the second stage titanium aluminizing of powder coat at a temperature of 1050 °C for 4 hours was carried out. X-ray diffraction, electron-probe, metallographic, durometric studies were conducted using known methods of physical materials science. Corrosion tests by gasometrical method were carried out.

Results. It is shown that as a result of saturation on the steel surface a multilayer coating is formed consisting of carbides of chromium, titanium, intermetallic compounds of titanium, aluminum, chromium. It has been established that the microhardness of multilayer coatings based on chromium carbides, titanium carbides, intermetallic metals is 5.8–34.0 GPA. It is shown that the application of complex coatings based on chromium, titanium, aluminum increases the resistance of U8A steel in many aggressive environments.

Conclusions. Complex chromium, titanium, aluminum saturation of U8A steel allows obtaining coatings with a total width of 27.5–30.5 µm, which ensures high corrosion resistance in various industrially important aqueous corrosive solutions.


Keywords


Steel У8А; Diffusion coating; Plating; Titanium aluminizing; Corrosion resistance; Microhardness

References


A.V. Golovanov et al., “The structure and phase composition of outer zone of steel after aluminizing”, Materyalovedenye i Termycheskaya Obrabotka Metallov, no. 6, pp. 42–45, 2008 (in Russian).

V.G. Khyzhnyak et al., “Titanium aluminizing of technical iron in the closed reactionary space in the chlorine medium”, Naukovi Visti NTUU KPI, no. 4, pp. 92–96, 2009 (in Ukrainian).

L.G. Voroshnyn et al., Theory and Technology of Thermochemical Treatment. Moscow, Russia: Novoe Znaniye, 2010, pp. 220–280 (in Russian).

T.V. Loskutova et al., “Diffusion chrome aluminizing of prechromized steel U8A”, Fizyko-Khimichna Mekhanika Materialiv. Problemy Koroziyi ta Protykoroziynoho Zakhystu Materialiv, no. 8, pp. 250–255, 2012 (in Ukrainian).

T.V. Loskutova et al., “Heat resistance of complex coatings obtained bychrome aluminizing of pre chromized steel U8A”, Visnyk SevNTU. Ser. Mekhanika, Enerhetyka, Ekolohiya, no. 120, pp. 151–155, 2012 (in Ukrainian).

P.A. Choquet et al., “Simultaneous chromizing and aluminizing of iron-base alloys”, J. Mater. Sci., vol. 121, pp. 413–418, 1989.

F.G. Geib and R.A. Rapp, “Simultaneous chromizing-aluminizing coatings of low-alloy steels by halide-activated pacl-cementation process”, Oxidation of Metals, vol. 40, pp. 213–228, 1993.

V.F. Loskutov et al., Carbide Coatings on Steel and Hard Alloys. Ternopil, USSR: Lileya, 1998, pp. 85–130 (in Ukrainian).

G.V. Zemskov and R.L. Kogan, Multicomponent Diffusion Saturation of Metals and Alloys. Moscow, USSR: Metallurgiya, 1978, pp. 55–73 (in Russian).

M.Y. Holdshteyn et al., Special Steel. Moscow, USSR: Metallurgiya, 1985, pp. 120–123 (in Russian).

Phase Equilibrium Diagrams of Binary Metallic Systems, N.P. Lyakisheva, Ed., vol. 2. Moscow, Russia: Mashynostroenie, 1997, pp. 604–607 (in Russian).

I.Ya. Smokovich et al., “Heat resistance and corrosion resistance of complex chromium+aluminum diffusion coatings on titanium alloy VT6”, Naukovi Visti NTUU KPI, no. 1, pp. 84–88, 2013 (in Ukrainian).

Directory Himika, B.P. Nicholas, Ed. Mosсow, USSR: Khimiya, 1968, pp. 880–887 (in Russian).

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GOST Style Citations


  1. Структура и фазовый состав поверхностного слоя на сталях после алитирования / А.В. Голованов, А.Г. Радюк,  В.И. Славов и др. // Материаловедение и термическая обработка металлов. – 2008. – № 6. – С. 42–45.
     
  2. Титаноалітування технічного заліза в закритому реакційному просторі в середовищі хлору / В.Г. Хижняк, М.В. Аршук, Д.В. Лесечко, Т.В. Лоскутова // Наукові вісті НТУУ “КПІ”. – 2009. – № 4. – С. 92–96.
     
  3. Ворошнин Л.Г., Менделеева О.Л., Сметкин В.А. Теория и технология химико-термической обработки. – М.: Новое знание, 2010. – C. 220–280.
     
  4. Дифузійне хромоалітування попередньо хромованої сталі У8А / Т.В. Лоскутова, С.С. Левашов, І.С. Погребова, В.Г. Хижняк // Фізико-хімічна механіка матеріалів. Проблеми корозії та протикорозійного захисту матеріалів. – 2012. – № 8. – С. 250–255.
     
  5. Жаростійкість комплексних покриттів, отриманих хромоалітуванням попередньо хромованої сталі У8А / Т.В. Лоскутова, В.Г. Хижняк, С.С. Левашов, І.С. Погребова // Вісник СевНТУ. Сер. Механіка, енергетика, екологія. – 2012. – № 120. – С. 151–155.
     
  6. Choquet P.A., Naylor E.R., Rapp R.A. Simultaneous chromizing and aluminizing of iron-base alloys // J. Mater. Sci. – 1989. – 121. – P. 413–418.
     
  7. Geib F.G., Rapp R.A. Simultaneous chromizing-aluminizing coatings of low-alloy steels by halide-activated pacl-cementation process // Oxidation of Metals. – 1993. – 40. – P. 213–228.
     
  8. Карбідні покриття на сталях і твердих сплавах / В.Ф. Лоскутов, В.Г. Хижняк, І.С. Погребова та ін. – Тернопіль: Лілея, 1998. – C. 85–130.
     
  9. Земсков Г.В., Коган Р.Л. Многокомпонентное диффузионное насыщение металлов и сплавов. – М.: Металлургия, 1978. – C. 55–73.
     
  10. Гольдштейн М.И., Грачев С.В., Векслер Ю.Г. Специальные стали. – М.: Металлургия, 1985. – C. 120–123.
     
  11. Диаграммы состояния двойных металлических систем / Под ред. Н.П. Лякишева. – М.: Машиностроение, 1997. – T. 2. – C. 604–607.
     
  12. Жаростійкість і корозійна стійкість комплексних хромоалітованих покриттів на титановому сплаві ВТ6 / І.Я. Смокович, І.С. Погребова, Т.В. Лоскутова, В.Г. Хижняк // Наукові вісті НТУУ “КПІ”. – 2013. – № 1. – С. 84–88.
     
  13. Справочник химика / Под ред. Б.П. Никольский. – М.: Химия, 1968. – C. 880–887.




DOI: http://dx.doi.org/10.20535/1810-0546.2015.6.52749

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