Study On Structure And Properties Of Al₂O₃-B₂O₃-SiO₂System Glasses Doped With Rare Earth Oxides

Electronic-grade glass fibers as a key raw material in copper clad laminate （CCL）, whichare the core link of the preparation of printed circuit boards. Recently, printed circuit boardsdevelop toward to high density, multi-layer and super multi-layer, which require CCL not onlyact as substrates but also posses the function of accurately control the characteristicimpedance, moreover act as passive components in multilayer boards. The key to achieve theabove functions is the low dielectric glass fiber cloth, which restric the development of CCL.Currently, commercial electronic glass fibers at home because of its high dielectric constant（εr=6.5） have not meet the needs of certain specific areas, glass fibers with low dielectricconstant become a hot research.Aluminumborosilicate system glasses （Al₂O₃-B₂O₃-SiO₂） as the basic system of lowdielectric glass fiber is an important inorganic non-metallic material, which has low dielectricconstant, good chemical stability and other properties. Rare earth oxides have a strongdissolving power in aluminumborosilicate system glasses, also the rare earth ions with highfield strength can improve the chemical stability of glass. Therefore, rare earth oxids dopedaluminumborosilicate become the composition system of low dielectric glasses, and thechanges in structure and properties become a research focus.Rare earth oxides doped aluminum borosilicate glasses were prepared by theconventional melt quenching technique. The major work of this article is to study the effect onstructure and properties of aluminoborosilicate glasses doped with rare earth oxides, andaccording to adjust the glass composition to obtain the glass composition ratio with the bestcomprehensive performance.According to the structure study of aluminumborosilicate glasses doped with differentrare earth oxides （La₂O₃, Ce₂O₃, Nd₂O₃, Sm₂O₃）, it is found that the loosen structure is in theorder La₂O₃<Ce₂O₃<Nd₂O₃<Sm₂O₃. According to the performance test，it is found that theglasses doped with La₂O₃posses the best thermal stability, chemical durability and lowdielectric constant and loss. Compared with glasses doped with different rare earth oxides, theglasses doped with La₂O₃further meet the performance requirements of the printed circuitboard substrate. In order to study the effect on properties of rare earth oxides doped glasses better, wecarry out the study according to adjust the content of La₂O₃as doping substance. It is foundthat the thermal stability and chemical durability of the glasses doped with La₂O₃areimproved, and the network structure is more compact. The dielectric constant and lossincrease in1MHz frequency, also they decreased with the increase of frequency（40Hz-1MHz）.On the basis of determining the glass system （La₂O₃-Al₂O₃-B₂O₃-SiO₂）, by adjustingSiO₂/B₂O₃and B₂O₃/Al₂O₃molar ratio to define glass composition and prepared glasses with amore stable structure, good chemical stability and easy-melting. It is found that the glassstructure first strengthen and then weak with the increase of SiO₂/B₂O₃mole ratio, whichattribute to boron abnormal phenomenon. The density first increases and then decreases.Dielectric constant increase and dielectric loss first decrease and then increase, dielectric loss isminimum when SiO₂/B₂O₃mole ratio is equal to3. Weight loss is minimum （0.442%）whenSiO₂/B₂O₃mole ratio is equal to3. The glass structure gradually weak with increasingAl₂O₃/B₂O₃mole ratio, and the density increase because of the molecular weight （Al₂O₃>B₂O₃）. Dielectric constant and loss gradually increase and acid resistance weak.