Theory 155/Ceramic sintering/Threshold lens
Densification Needs a Grain Threshold
The claim
Full densification requires grains to stay below a threshold size, because grain boundaries are the diffusion path.
01Mechanism
Grain growth removes boundary area; once grains exceed the threshold, diffusion cannot close the remaining pores.
02Prediction
Final density should track grain size.
03Refutation
Density tracking sintering time would remove grain growth.