Influence of working parameters on the composite electrodeposition

Abstract

Composite materials are extensively studied, especially in recent years, which have a wide application in industry. Among these composite materials, in this paper we studied about electrolyte composites obtained. The matrix is made up of particles of Ni-P on which have been deposited Si-C hard particles. The amount of phosphorus incorporated into the layer increases with increasing the content of phosphorous acid in the electrolyte. The content of phosphorus incorporated into the coating composition evolves as both solid as well as particle-free solutions. When the content of phosphorous acid in the electrolyte is low and where alloys are micro crystallized, the presence of particulates changes a little the phosphorus content. At the increase of phosphorus content included in the coating is observed that the incorporation of phosphorus is higher for increasing the amount of silicon carbide particles. This matrix study was done according to the amount of phosphorus in the deposited layer. The co-deposited phosphorus modifies the crystallization mechanism so the super saturation nickel network by phosphorus allows the inhibition of the growth of nickel crystallites whose size decreases until the complete amorphization of the solid solution. The development of these deposits was aimed at determining the influence of the variation of phosphorous acid in the electrolyte, and therefore the change in the content of phosphorus included in the layer for the SiC particulate, on the one hand, and, on the other hand, it was intended the influence of heat treatment on the deposition hardness. After the measurements, it is noted that the layer thicknesses are higher for the deposition obtained from electrolyte with small containing of phosphorous acid. The structure of the Ni-P alloy and the composite material Ni-P / SiC, depends on the amount of phosphorus contained in the layer and varies from the crystalline state (the low content of phosphorus) to the amorphous state (the high content of phosphorus). Metallographic investigation and X-ray diffraction on the P20S40 sample structure reveals the existence of nano-crystalline state of the layer, and it is noted that the grains of Ni-P alloy is lower than that incorporated SiC particles that are more evident. Following heat treatment, it was found that the microcrystalline structure of the deposits, consisting of a solid nickel solution supersaturated in phosphorus, is maintained up to 463 K, and at higher temperatures it is producing the precipitation of the Ni3P compound into the nickel matrix.