Binder burnout

Part II. Ceramic Powder S5mthesis Part III. Ceramic Paste Formation Mise-en Pate Part IV. Green Body Formation Mise-en Forme Part V. Presintering Heat Treatments of Drying and Binder Burnout... 

As a result, a picture of the microstructure is a valuable tool in diagnosing drying problems in green body manufacture and predicting problems during binder burnout and sintering. 

A small amount of polymer can produce an enormous volume of gas, which must be removed from the porous green body. The flow of this gas in the porous network of the ceramic green body can create a pressure build-up which puts stress on the green body. The stress induced by flow and temperature gradients in the green body are also discussed, so that binder burnout conditions can be selected to prevent cracking of the green body. 

A complete picture of polymer thermal degradation is clouded because multiple reaction mechanisms can be operable for a single polymer at a single temperature, leading to a host of volatile products and residues. Therefore, one has to consider the relative rates of these competing reactions to establish an optimized and controlled binder burnout. 

P is the number of polymer molecules of degree of polymerization n, R is the number of radicals found in a volume V, R is the number of polymer radicals with degree of polymerization n found in a volume, V. For other definitions, please use the nomenclature associated with Table 15.2. Noting equation 15.14, the kinetics of polymer degradation are very complex. Only the most simple mechanisms have been thoroughly researched. These simplified reactions presented in Table 15.2 are sometimes zero order, more frequently first order, and infiiequently second order in polymer mass. These simplified rate expressions are typically used to model binder burnout. 

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 ... 

Fundamental studies in the literature of the kinetics of binder burnout are scarce. This material has been developed by synthesis of several articles [3,10,46,47] and the application of principles of gas—solid reac-... 

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