Titanium di:oxide contg. glass of high mechanical strength - is produced by single or double crystallisation heat treatment process

摘要

Ceramic glassware contg. TiO2 has a compsn. in wt.% 45-70 SiO2, 10-35 Al2O3, 8-25 MgO, 7-15 TiO2. It is converted by a secondary heat treatment into a glass crystalline material with as its main phase enstatite, spinel and t-quartz. The content of TiO2 is pref. 10-15 wt.%. To produce the glass ceramic structure having the high degree of stress resistance the object produced is annealed at 900-1500 (900-1050) degrees C. The temp. is raised to the crystallising point at 1-2 degrees C/min and maintained at pref. 900-1050 degrees C for 1-2 hrs. Alternatively, the glass object is heated to a temp. of 30-90 degrees C above the Tg point of the glass as determined dilatometrically, and maintained in this range for 3/5 hr. Then the temp. is raised at 3-4 degrees C/min. to the crystallising temp. of 900-1400 (900-1050) degrees C and held there for 1-2 hr. The glassware has a high degree of resistance to breaking by bending stresses, a high level of chemical resistance and good resistance to temp. changes. The resistance to breakage reaches as value of 8-9 times that of the starting material. It is used for pipelines in the chemical industry.