Binder burnout oxidative

The effects of oxides on the binder burnout of poly(vinyl butyral) (PVB) was studied by Masia et al. [26]. The binder decomposition kinetics in air was shown to be a strong function of the ceramic oxide present. In all cases, the oxide decreased the temperature necessary for thermal decomposition compared to PVB alone. The order was the following ... 

To discuss binder burnout in detail, let us consider a spherical green body of radius R with a polymer completely filling its pores undergoing an oxidative thermal decomposition. Figure 15.9 is a schematic of this process. We will use the case where the number of moles of oxygen, n, is 1 that is,... 

Accounting for these rate determining steps the kinetics of binder burnout can be established for simple decompositions of polymers, such as depolymerization and the oxidation of carbon. For polymers with... 

The formulation selected is a high-surface-area silicon carbide powder that can be sintered in a reducing atmosphere or a neutral atmosphere. The binder burnout has to be done in an oxidizing atmosphere below the oxidation point for the SiC. The powder had a surface area of > 15 mVg. 

Masla, S., Calvert, P.D., Rhine, W.E. and Bowen, H.K. Effects of Oxides on Binder Burnout During Ceramic Processing. J. Mater. Sci. 1907-1912 (1989). 

The binder as well as the other additives used to aid the forming of the green body must normally be removed as completely as possible (commonly by pyrolysis) prior to sintering. The concentration of the binder is commonly much greater that that of the other additives, so the burnout characteristics is of primary importance in the selection of the binder. As discussed in detail later, the burnout characteristics depend primarily on the binder chemistry and the atmosphere (oxidizing or nonoxidizing). 

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