Concepção e processamento de material compósito para otimização de performance tribológica: abrasão e erosão

Abstract

Wear is a phenomenon that is present in many industrial activities. When it is not a desired effect, production losses, risks to workers' safety and environment pollution are some of its consequences. In order to reduce the wear, the correct selection of coating to protect the work surface, aiming to a life-time increase of the equipment, is one option.In this market, the growth in the use of composite materials is observed, because they provide to the tribosystem adequate properties, which appear to be antagonistic: fracture toughness and hardness, thixotropy and stiffness, high technology and low cost. The main objective of this work is to understand the design of a refractory composite material, identifying through analysis of its process and the characterization of themechanical resistances and fracture toughness the main properties that influence the tribological performance. Three types of different refractory concretes were studied. The raw materials were characterized by chemical composition, crystalline phases, scanning electron microscopy, grain size and apparent density. The resulting properties of the processing were measured: flow, apparent porosity and bulk density. Thematerials were submitted to tests of cold crushing strength and fracture toughness through the elasticity modulus. Finally, they were tested on abrasive wear of rubber wheel and erosive through steam of silicon carbide particles, correlating the results with the properties. Fracture toughness was the most important property for the highest resistance to abrasive and erosive wear. The higher amount of aggregates with highfracture toughness generated the highest resistance to erosive wear because of the shadow effect, while the harder aggregates increased, even in less amount, the resistance to abrasive wear. The marks that each type of wear register on the coating have been identified. The studies and parameters tested allowed a comparison with a practical case in the industry, identifying the type of wear that occurs in the field andcorrelating with the results of the laboratory tests