Chromium Carbide Coatings Produced with Various HVOF Spray Systems

Abstract
High velocity oxy-fuel (HVOF) experiments were carried out with Diamond Jet (DJ) 2600 and 2700, P-5000, Jet Kote and Top Gun to investigate the influence of the spray system and of the spray parameters on microstructure and properties of Cr3C2-NiCr coatings. The results show that with all applied HVOF systems Cr3C2-NiCr coatings of high density, high bond strength and high wear resistance can be produced. However, microstructure and properties of the coatings mainly depend on the degree of oxidation and carbon loss of the material during the spray process. Due to the relatively low heating of the spray material the decarburization of CrsCa-NiCr was found to be very low using the HVOF systems DJ 2600, DJ 2700 and JP-5000. Additionally favored by the increased particle velocities coatings sprayed with the Diamond Jet systems and the JP- 5000 exceed coatings produced with the traditional HVOF systems with regard to hardness, wear resistance and bond strength.