Research on the Effect of Density on the Outgassing Characteristics of Ceramics

In order to systematically assess the influence of the internal structure on the outgassing property, alumina ceramics with different porosity were first prepared by four sintering processes, and then their measurements of the outgassing rate and desorption gas components were performed using the throughput method. Experimental results show that when the alumina sample is exposed to vacuum for just a few hours, surface outgassing dominants and the main outgassing component is water vapor. After sufficiently long vacuum extraction, the gas inside the alumina ceramic is gradually released. In this test, the gas released from the internal structure plays a dominant role after 48 h pumping of 600 L/s. Combined with the microstructure analysis, it is further concluded that the denser the alumina structure is, the lower the vacuum outgassing rate is and the lower the partial pressure of the individual gas components is. It can also be observed that the internal structure still has some influence on the outgassing characteristics of the material, although to a slightly lower degree than the surface properties compared to previous studies.