| 摘要 |
The present invention relates to glass-ceramic materials,-processes for making the same and articles comprising the same... The glass-ceramic material has a composition, by weight of the total composition, comprising 55-68% SiO 2 ; 18-24% Al 2 O 3 ; 3.3-4.1% Li 2 O; 1.5-4.0 % ZnO; 1.5-5.0% MgO; 2-5% TiO 2 ; 0-2% ZrO 2 ; 0-5% B 2 O 3 ; 0-8% P 2 O 5 ; 0-2% Na 2 O, 0-2% K 2 O; and at least one component resulting from an effective amount of at least one fining agent; wherein: the total of B 2 O 3 and P 2 O 5 is at least 1.5% by weight, the total of MgO and ZnO is at least about 3.5% by weight, the total of Na 2 O and K 2 O is less than about 3.0% by weight, the total of P 2 O 5 , B 2 O 3 , Na 2 O and K 2 O is less than about 11 % by weight, the weight ratio of the sum total of Na 2 O+K 2 O to the sum total of P 2 O 5 +B 2 O 3 Na 2 �¢ O + K 2 �¢ O B 2 �¢ O 3 + P 2 �¢ O 5 is less than about 0.5; advantageously the total of P 2 O 5 , B 2 O 3 , Na 2 O and K 2 O is less than about 9% by weight and the total of Na 2 O ad K 2 O is less than about 2% by weight; and more advantageously the total of P 2 O 5 , B 2 O 3 , Na 2 O and K 2 O is less than about 7% by weight and the total of Na 2 O ad K 2 O is less than about 1% by weight. The glass-ceramic material comprises ²-spodumene solid solution as the predominant crystalline phase. In certain embodiments the glass-ceramic material of the present invention is essentially free of As 2 O 3 and Sb 2 O 3 , and comprises about 0.3-1.2% by weight of SnO 2 and 0-1% of CeO 2 . The precursor glass for the glass-ceramic material of the present invention can be melted at below about 1600°C and cerammed into ²-spodumene glass-ceramic at a relatively low temperature and in a relatively short period of time. The glass-ceramic material is especially advantageous for use in the production of cooktop plates and cooking utensils. |
