Diffusion Coatings as Corrosion Inhibitors

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Corrosion is the cause of irretrievable loss of huge amounts of metals and alloys. The harmful effects of corrosion can be reduced significantly by applying appropriate methods of corrosion protection. One method to protect metals against corrosion is the formation of diffusion coatings on them. High corrosion resistance is typical for the boride diffusion layers. Aluminothermy is one of the main methods for diffusion saturation of the surface of metal products with various elements, including boron, and under certain conditions with aluminum, too. Samples of steel 45 were put to aluminothermic diffusion saturation with boron in a pressurized steel container at a temperature of 1100K, for 6 hours in powdered aluminothermic mixtures. The content of В2О3 in the starting mixtures decreased from the optimum - 20% to 0%, and the content of Al and the activator - (NH4)2.4BF3 is constant, respectively 7% and 0.5%. Al2O3 was used as filler. The borided samples were tested for corrosion resistance in 10% HCl for 72 hours. The results show that their corrosion resistance depends on the composition of the starting saturating mixture (mainly on the content of В2О3), and respectively on the composition, structure, thickness and degree of adhesion of the layer to the metal base.

[1]. Borisenok, G., Chemical-heat processing of metals and alloys, Directory, M., Metallurgy, 1981, 296-312.

[2]. Chchłowski, M.; K. Przybyłowicz, M.; Chochlowska, Aluminotermiczne borowanie stali w proszkach, Metaloznawstwo i obrobka cieplna, 1986, 79, 12-17.

[3]. Dimitrov, R., Inorganic Chemical Technology, Pigmalion, Plovdiv, 1995.

[4]. Ivanov, R., Aluminothermic Diffusive Saturation of Steel 45 with Boron, “Amtech`07”, 2007, 97-101.

[5]. Ivanov, R., Aluminothermic Diffusive Saturation of Steel with Boron and Aluminium, Annual of Shumen University, XVIII B2, Faculty of Natural Sciences, 2008, 156-165.

[6]. Ivanov, R., Influence of the Mode and the Quantity of Alloyng Additions in Aluminothermic Boriding Mixtures on Indexes of the Obtainedd Boriding Layers, “Unitech`08”, 2008, 2, 104-107.

[7]. Ivanov, R., Two-Component Diffusive Steel Saturation, Materials and Manufacturing Processes, 24 (7), 2009, 894-897.

[8]. Ljahovich, L., et al., Multicomponent Diffusion Coating, Naukovaja dumka, Мinsk, 1974, 99-118.

[9]. Matuschka, A.; G. Kunzel, Metall, 1985, 30(4), 336-338.

[10]. Raychev, R.; L. Fachikov; V. Zaprjanova, Corrosion and protection of the materials - Handbook for laboratorial exercises, Sofia, 2002.

[11]. Uzunov, N.; R. Ivanov, Aluminothermic powder boriding of steel, Applied Surface Science, 2004, 225, 72-77.

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