The invention relates to a
rare earth-mixing high strength
lithium bisilicate sitall material and a preparation method thereof. Parent glass of the invention includes the following components according to
molar percentage: 61.2 to 66.0 percent of SiO2, 0 to 2.5 percent of B2O3, 0 to 1.6 percent of Al2O3, 1.0 to 3.7 percent of P2O5, 0 to 2.3 percent of ZrO2, 1.0 to 1.8 percent of K2O, 24.2 to 31.8 percent of Li2O, 0 to 2.0 percent of MgO, 0 to 2.0 percent of CaO, and 0.5 to 4.2 percent of La2O3+Y2O3. A corresponding
raw material prepared from the oxidates is processed by the steps of ball milling, 80 mesh
sieve sieving and uniform mixing to obtain a batch; the batch is led into a copple to be melted after the temperature from 1480 to 1520 DEG C is maintained for 2 to 3 hours, and the melted batch is cast into a stainless steel mould to be molded and then is annealed at 500 DEG C for 0.5 hour; and the step of
coring is carried out in a resistance furnace at the temperature from 500 to 550 DEG C for 1 hour, and the step of
crystallization is carried out at the temperature from 600 to 850 DEG C for 2 hours. The
crystallization degree of the sitall is as high as 60 to 70 percent, the
flexural strength is 100 MPa or more higher than the sitall to which the
rare earth oxides are not added, the highest
flexural strength reaches 334 MPa, the maximum
elastic modulus reaches 143 GPa, and the highest
fracture toughness reaches 3.34 MPa-m. The sitall of the invention has favorable stability, and the heat treatment temperature is lower and is easy to control.