Effect of Heating Rate on Sintering and Coarsening

Abstract

The sintering of zinc oxide powder compacts has been investigated at constant rates of heating of 0.5° to 15°C/min. For samples with the same initial relative density (0.50), the temperature derivative of the densification strain versus density fits within a single, relatively narrow band. At low temperatures the densification rate as a function of temperature increases almost linearly with the heating rate. The data, covering a wide density range of 0.5 to 0.98, are consistent with an analysis that accounts for the coarsening (defined as an increase in the mean pore separation) in terms of two classes of microstructural coarsening processes: those associated with densifying and with nondensifying mechanisms.

Effect of Green Density on Densification and Creep During Sintering

“…It may be conjectured that this onset of rapid coarsening coincides with reaching closed porosity when lower activation energy processes, such as surface diffusion, can no longer operate. These findings and considerations are in agreement with an earlier study on coarsening and densification in zinc oxide by Chu et al (20). While direct confirmation from extensive microstructural examination are needed to establish fully the validity of the behavior of the interpore spacing during coarsening, the current findings…”

Two‐Step Sintering of Ceramics with Constant Grain‐Size, I. Y2O3

“…15,16 Analysis of sintering data requires a sound physical model. Although theoretical models usually use idealized geometric assumptions which may not hold in real materials, 8,10,11,[17][18][19][20][21][22][23][24][25][26] a general dimensional argument originated by Herring 27,28 states that the normalized rate of densification, via grain boundary diffusion, can be expressed as…”

Investigação da cinética de sinterização para o estágio inicial no sistema SnO2: ZnO

“…As equações de Bannister [13] apresentam também a condição de que no intervalo de aplicação, não deve ocorrer crescimento de grão, que é um mecanismo não densificante, de acordo com o trabalho teórico de Chu [15] sob condições onde não ocorre crescimento de grão a densificação é proporcional a retração linear que por sua vez é proporcional à taxa de aquecimento elevada a potência -1,4.…”

“…Dentre os modelos cinéticos pode-se destacar os de Woolfrey-Bannister [13], Wang-Raj [14] e Chu-Rahaman-De Jonghe [15], Johnson [12], Young-Cutler [16], para sinterização sob taxa constante de aquecimento (TCA).…”