STUDY ON THE EFFECT OF ALUMINA (Al2O3) ADDITION ON THE COMPOSITE WC-3% Ni SINTERIZED WITH LIQUID PHASE
Composite, hard metal, nickel
The need for materials with high performance has driven the study of new systems as an alternative to existing ones. The composite materials are indicated when there is this necessity, therefore, can unite characteristics of different materials in a single body. A composite well known for its properties is tungsten carbide and cobalt (WC-Co). It is known that the mentioned material presents high hardness being indicated for use in cutting tools, however, as the cutting speed increases, the studies indicate that there is oxidation, thus generating a break in the composite. As an alternative to the WC-Co system, the cobalt substitution is currently studied by nickel, however the WC-Ni composite presents a low hardness when compared to the WC-Co. The present study proposes the study of a new material, which is a mixture of carbide of tungsten, alumina (Al2O3) and nickel. The study aims to establish characteristics of the composite WC-3% Ni when added with 5, 10 and 15% w Al2O3. The process of obtaining it was via powder metallurgy. High energy milling (400 rpm), uniaxial compaction at 400Mpa and vacuum sintering were carried out and in a dilatometric oven at temperatures of 1450 and 1550 ° C with a sintering level of 1h. The samples were characterized by: laser particulometry, XRD, SEM, hardness, density and densification of the samples. The results were promising since there was interaction between WC-Ni in all compositions. The sintering in dilatometric furnace presented better densities and hardnesses being the composition with addition of 5% p of alumina the more dense in the two processing temperatures, with relative density superior to 90%.