Influence of binder content on physical and mechanical properties of composite materials such as metal powder-waxy substance

Abstract

The scientific basis for the development of working materials from waxy highly filled composites for FDM 3D printing using is not yet sufficiently developed. The need to develop such composites is due to the fact that highly filled waxy composites, on the one hand, have low 3D printing temperatures, and on the other hand, the fact that the waxy substance has a low ash content and is completely removed during annealing and subsequent sintering of the residual framework from the filler. Therefore, in this work, the influence of the binder content on the physical and mechanical properties of composite materials such as metal powder - waxy substance in the ratio of metal to waxy substance, as 50/50, 60/40, 70/30, 80/20 % (by volume), as well as the shape change of composite samples when they are heated at a temperature from 61 to 230 °C. Carbonyl nickel and carbonyl iron were used as metal powder, and beeswax and paraffin were used as a binder. It was found that the developed surface of particles significantly affects the density dependence, the microhardness and compressive strength of composites from the binder content, the actual density of the composite samples after pressing is less than the calculated by the additivity formula with the binder content up to 40 % (by volume) and only with an increase in the binder content to 50 % (by volume) does the actual density approach the calculated additive; the developed surface of nickel particles several times increases the strength of the composite in comparison with iron at the same binder content, at the same time, the dependences of the microhardness differ significantly: on Ni-wax samples, it tends to decrease with an increase in the wax content, and on samples Fe-paraffin - to an increase, which is due to the influence of such phenomena as adhesion and cohesion, mechanical adhesion. The level of strength of composite samples with a binder content of 40-50 % (by volume) is sufficient so that they do not collapse not only in 3D print head The resulting experimental data can be extended to other similar systems when creating working materials for FDM 3D printing based on carbonyl nickel and iron powders.