Isothermal/isobaric CVI

According to the controlling parameters used in the process, CVI approaches can be classified into five typical categories [9] isothermal/isobaric CVI (I-CVI), forced-flow CVI (F-CVI), thermal gradient/isobaric CVI (TG-CVI), pulsed CVI (P-CVI) and liquid immersion CVI (LI-CVI). There are more than ten CVI techniques if a particular method is coupled with plasma, microwave or a catalyst to enhance the process [10], Some representative techniques are discussed in this chapter as follows. 

For isothermal/isobaric CVI processes there is no forced flow, i.e. the convection term cannot be taken into consideration. Assuming the first-order reaction, Equation (5.2) becomes... 

Isothermal and isobaric CVI (I-CVI), a relatively easy and the oldest hot-wall technique, is still widely used in research and in industry. The key feature of this approach is that both temperature and pressure are kept constant during the infiltration process. Because of this its main advantage is good consistency of the finished product due to strict yet easy thermal and pressure parameter control. In particular a large number of complex preforms can be densified simultaneously, as shown in Figure 5.2. 

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