| Crystalline glass is also called crystal glass, which has a higher refractive index and transmittance, bright and clean exterior, metal texture. What's more, the chemical stability of it is reliable and can be reused. So it is widely used in making handicraft, catering tea set and as a packaging material. Common crystalline glass refers to the generalized crystalline glass, which is named the lead crystal glass. But with the awareness of environment protection enhancing by people and the controlling of lead by many countries through the related laws, PbO is gradually forbidden. Therefore, it is high time for us to do research on lead-free crystal glass and finding the constituent which can take the place of PbO is the key point at the moment.In this paper, we chose R2O-CaO-SiO2 crystal glass whose preparation techniques were very mature at present to do our research. Based on this kind of system, we mainly added some oxides in it and then analyzed how they made effect on the glass' structure and properties. The basic component were SiO2 61.8～67.8mol%,Na2O 4.3～10.3mol%,K2O 2.7～8.7mol%,CaO 5.3～11.3mol%,BaO 1.66～7.66mol%,ZnO 4.68mol%,TiO2 1.6～7.6mol%. In this essay, we selected five different kinds of oxides:Bi2O3, SnO2, Nb2O5 and the rare earth like CeO2, La2O3. Different kinds of lead-free RCS crystal glass were prepared in our research with each single oxide mixed, the content of which was between 0.01～0.05mol. The effect of additions on the structure, refractive index, transmittance, density and chemical stability were studied in the crystal glass by means of Raman, FT-IR, V-rectangular prism refractometer, spectrophotometer and so on. Through the above research, we draw the following results:When the content of Bi2O3 admixture was between 0.01～0.05mol, it didn't take part in forming the network frame in the glass, but provided the non-bridgingoxygen and made the network broken just as a network modifying oxide. Besides, Bi2O3 could obviously improve the refractive index and density while the transmittance declined in the wave of 308～760nm. And when Bi2O3 is 0.05mol, dmax is 3.6262g/cm3 and nD is 1.5906 which reached the level of lead glass. Bi2O3 was one of the most efficient components in improving nD.However, the water resistance increased after it fell firstly. Adding Bi2O3 made the resistance to acid and alkali went down.When the content of SnO2 was between 0.01～0.03mol, the connection of the network frame became stronger with the increasing of SnO2 while Sn4+ was in the gap of the network. However, when the content was between 0.03～0.05mol, the network became much weaker and the number of non-bridgingoxygen increased. Maybe, more Sn4+ was beyond the gap. Besides, refractive index and the density increased gradually, but its contribution to them was much lower than the same amount of Bi2O3. When the content of SnO2 was 0.05mol, dmax=3.0179g/cm3, nDmax=1.6092. And the transmittance was about 80.8%～91.5% in the wave of 380～2000nm. The water resistance, acid resistance and alkali resistance declined after it increased and the chemical stability was much better at the point of 0.03mol. And the comparison of the mass loss is alkali>acid>water. B3 was the much better glass in this group.When the content of Nb2O5 was between 0.01～0.05mol, with the increasing of Nb2O5, the number of the non-bridgingoxygen declined and the connection of the network frame became stronger as Nb5+ had the ability to gather the network together. While Nb2O5 was increased, refractive index and the density were improved. When the addition of Nb2O5 was 0.05mol, nDmax was 1.6264 and dmax was 3.0179g/cm3. The light almost couldn't pass through the near-ultra violet rays while the transmittance was between 88～91.5% in 380～2000nm. Besides, the alkali resistance was improved obviously. Nb2O5 was a very high-efficiency oxide in promoting the chemical stability. When the addition was 0.05mol, the glass was the better one in group C.CeO2 could make the network become stronger and closer at a certain range, but appeared the reverse effect when it was beyond the range. The radius of Ce4+ was so small that it could easily filled in the gap of the network and played the role of network decoration. The refractive index and the density were promoted as the CeO2 increased and dmax was 3.0258g.cm-3, nDmax was 1.6087. And the transmittance was about 82% in the Wave of 380～2000nm. The water resistance was the best at the point of 0.04mol while the acid and alkali resistance were the best at the point of 0.05mol. CeO2 has a certain ability in improving the chemical stability.When the content of La2O3 was between 0.01～0.05mol, it made the connection of Si-O-Si, Ti-O-Si become weaker and structure of the glass become flabby and it was considered as the network decoration. The density and refractive index were improved as it increased and dmax was 3.1667g.cm-3, nDmax was 1.6164 which achieved the level of lead crystal glass containing 24% PbO. In the area of 380～2000nm, the transmittance was between 88～91% and a higher addition was much better in improving it. The water resistance was increased but fell at the point of 0.03mol while the acid and alkali resistance were promoted. When the addition was 0.05mol, the homologous glass was the much better one in the group adding rare earth. |
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