This study compares high-velocity oxygen fuel spray MJP5000 and MJP 6000 (Patented by Metallizing Equipment Company Pvt Ltd.) using powder WC-Co-Cr. The microstructure and phase composition of powders and coatings will be analyzed by scanning electron microscopy and X-ray diffraction. Coatings were also characterized by their hardness, bond strength, roughness, deposition efficiency. Therefore, coating of high hardness and wear resistance can be produced with all HVOF spray system when the proper spray powder and process parameters are chosen. The results demonstrate that the powder exhibits various phase transformation during the spray process depending on type of powder, spray system and spray parameters.

A new variant of LVOF system was developed to deposit ceramics. For this study Cr 2 O 3 powder was used. To save on time and reduce mathematical iterations optimizing of parameters was carried out by using an online particle diagnosing system. The spray parameters were varied to study their influence on the particle in-flight characteristics. The parameters which gave best particle temperature and velocity was used for coating. The resulted coating was dense and hard.

NiCrBSi spray and fuse types of coatings are routinely applied on various jobs where metallurgical bond of the coating to the substrate is desired. These coatings require a subsequent fusing operation at temperature of about 1050°C. In the present study NiCrBSi coatings were formed by the HVOF process and by the conventional spray and fuse route. The coatings were characterized for their microstructure, hardness and porosity. The aim of this study was to see whether HVOF spraying NiCrBSi spray and fuse powder could cause instant fusing of the coating without the need for additional fusing operation. XRD study of the coatings was also carried out to find out the difference between the spray and fused NiCrBSi coatings and the HVOF sprayed coatings. The HVOF spraying of NiCrBSi was carried under different set of parameters to determine the effect of spraying parameters on the properties of coating.

The high velocity combustion wire (HVCW) sprayed coatings have unique structures and properties which are different from the conventional wire / powder HVOF coatings. This paper studies the coatings of 0.8% C Steel formed by the HVCW system. 0.8% C Steel coatings formed by the HVCW system were studied for their wear resistance (pin on desk wear test) and phase composition. Methods like SEM with Wavelength Dispersion Spectroscopy (WDS) attachment were utilized for determining the composition of the coatings. Microhardness and tensile bond strength of the coatings were also ascertained. A set of conventional oxy-acetylene wire flame spray coatings of 0.8% C Steel were also prepared and these coatings were then compared with the HVCW coatings. Possible applications of the HVCW coatings are discussed based upon the properties of the coatings.

This paper assesses the performance of a supersonic flame spraying gun along with the quality of molybdenum coatings produced with it. The hardness of the wire sprayed molybdenum was compared to coatings made using conventional flame spraying methods. The coatings were also evaluated for porosity, bond strength, and phase distribution by X-ray diffraction. The results indicate that the supersonic gun performs better than conventional flame spray equipment when depositing refractory metals such as molybdenum.