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8008 |
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Wednesday, May 01, 2024, Yellow 1 9:40 AM Powders, Wires, Suspensions |
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Chromium carbide and tungsten carbide containing powders for thermal spraying |
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Guido Reisel* / Oerlikon Metco WOKA GmbH, Germany Annett Dorner-Reisel / Hochschule Schmalkalden, Ville Eronen/ Oerlikon Metco Europe GmbH, |
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Thermal sprayed coatings of tungsten carbide (WC) in a cobalt or nickel base matrix are often used in applications which require wear and corrosion protection. Feedstock powders produced by agglomeration and sintering exhibit a spherical shape with a certain inherent intra-particle porosity. The cobalt matrix is often alloyed by chromium to increase hardness, corrosion and wear resistance, which is necessary in many applications, e.g. in paper or hydroelectric industry. The most common chemical composition in nowadays is WC10Co4Cr. Unfortunately, tungsten and cobalt are both listed from European Union as critical raw materials. Therefore, it would be good to have alternatives available, which at least reduces the amount of tungsten carbide and cobalt, but still shows similar properties as thermally sprayed coatings. Powders, which contains in addition to tungsten carbide chromium carbide and uses nickel-based metal matrices, are of high interest as they reduce the amount of WC and Co. Among the already since the early 1960s developed composition WC20Cr3C27Ni, a new composition with still higher chromium carbide content of 45 weight percent was introduced some years ago. The aim of the presented work is to evaluate the properties of coatings applied by high velocity spray techniques from powders, which contains both chromium carbide and tungsten carbide in comparison to WC based coatings to prove that these materials are an attractive alternative to WC10Co4Cr. |