Oxy-Acetylene Flame Thermal Spray of Al/SiCp Composites with High Fraction of Reinforcements

Abstract

Aluminum matrix composites reinforced with more that 50 vol.% of SiC particles were fabricated using oxyacetylene thermal spraying. The sprayed material consisted of mixtures of aluminum powder with 60-85 vol.% of SiC particles. To favor the processing of the composite, in some cases, the SiC particles were coated with silica following a sol-gel route. This allowed obtaining as-sprayed samples with thickness above 2 mm and with porosity values below 2%. Post-processing of the samples by hot pressing allowed to reduce further the porosity of the composites and to enhance their microstructural homogeneity. The whole process of spraying and hot pressing has been optimized and the role played by the different spraying parameters and by time length and temperature of hot pressing has been also studied.

Evaluation of the Wear Resistance and Corrosion Behavior of Laser Cladding Al/SiC Metal Matrix Composite Coatings on ZE41 Magnesium Alloy

“…The deposition efficiency of the Al40Si/SiC coating According to this equation, the deposition efficiency of the Al12Si/SiC coating was 19%. This value is similar to the efficiencies obtained by other deposition techniques of composite materials such as [28,29].…”

Effect of flame spray deposition parameters on the microstructure, microhardness and corrosion resistance of FeNbC coatings on AISI 1020 steel

“…A higher magnification of coating cross-section indicated by the dashed line is shown in figure 3(b), where splats are observed parallel to the substrate surface and some porosity regions formed during the cooling process. In several thermal spraying methods the molten or semi-molten particle of the feedstock is accelerated against a substrate, they deform during impact and anchor mechanically on the irregular surface, thereafter on each previously solidified layer, thus giving rise to a multilayer coating with lamellar structure [28,33]. Unmelted particles and interlamellar cracks are also observed, indicating an inefficient metallurgical bond.…”

Corrosion of Magnesium-Aluminum Alloys with Al-11Si/SiC Thermal Spray Composite Coatings in Chloride Solution

“…The substrate/coating interfaces presented some roughness because of the sand blasting pretreatment. Al-11Si/SiCp-(TS) coatings, with an average thickness of 530 ± 45 lm, revealed a very rough surface ( Table 2) and interconnected pores and microchannels distributed in the deposited layer and substrate/coating interface, which are the common features of as-sprayed Al-based coatings ( Ref 11,12,14,15,19,20,24,25). Pores were located between the sprayed Al-11Si particles and at the Al-11Si/SiCp interfaces, being bigger for the latter (Fig.…”

“…Also, at the magnification used, there was no formation of interfacial products, like Al 4 C 3 , at the Al-11Si/SiCp interfaces. Self/inter-diffusion processes and formation of intermetallic compounds are more often observed when post-heat treatments are applied ( 21,25,26). …”