POST SINTERING HEAT TREATMENTS AND CREEP OF Si-Y-Al-O-N CERAMICS T. CHARTIER, J.L. BESSON, P. GOURSAT et W. MUSTEL J. Phys. Colloques, 47 C1 (1986) C1-673-C1-678 DOI: 10.1051/jphyscol:19861103