Lead-free solder glass

Abstract

The invention relates to lead-free solder glass, which comprises the following raw materials in percentage by weight: 35-55% of bismuth oxide, 15-25% of boron trioxide, 15-35% of zinc oxide, 0.1-10% of barium oxide, 0.1-10% of cuprous oxide, 0.1-10% of magnesium oxide, 0.1-10% of silicon dioxide, 0.1-10% of aluminum oxide, 0.1-3% of manganese dioxide, and 0.1-3% of titanium dioxide. The solder glass is lead-free, can realize lead-free electronic products under the condition of keeping a lower glass softening temperature, has the characteristics of low softening temperature, excellent chemical stability, large resistivity, and good mobility, is powerfully competitive in the aspects of lead free and excellent performance, and has high cost performance and wide market development prospect.

Description

【Technical field】 [0001] The invention relates to the field of chemical industry, in particular to a lead-free solder glass, which has the characteristics of low softening temperature, good chemical stability, high resistivity and good fluidity. 【Background technique】 [0002] The existing solder glass for electronic paste contains a large amount of heavy metal lead. Lead is one of the six metals used by humans at the earliest. It is harmful to human health and can accumulate in the body to cause lead poisoning. The effect of lead poisoning is quite Slow and stealthy, it is not easy to detect the toxicity before it appears. Lead is a cumulative poison, which is easily absorbed by the gastrointestinal tract, part of which destroys the blood to decompose red blood cells, and part of it spreads to the organs and tissues of the whole body through the blood and enters the bones. However, lead compounds deposited in internal organs and bone marrow are excreted very slowly from th...

AI Technical Summary

Problems solved by technology

The sintering temperature of the paste made of the glass powder of this patent is 800-900°C, and the time is 5-15 minutes, which shows that this kind of glass powder is suitable for high-temperature sintering, and cannot be used for electronic pastes that are sintered at low or medium temperatures.

[0010] U.S. Patent No. P5153151 discloses a phosphate solder glass whose molar composition is, Li 2 O: 0-15%, Na 2 O: 0~20%, K 2 O: 0-10%, ZnO: 0-45%, Ag 2 O: 0-25%, Tl 2 O: 0-25%, PbO: 0-20%, CuO: 0-5%, CaO: 0-20%, SrO: 0-20%, P 2 o 5 : 24~36%, Al 2 o 3 : 0~5%, CeO 2 : 0~2%, BaO: 0~20%, SnO: 0~5%, Sb 2 o 3 : 0~61%, Bi 2 o 3 : 0~10%, B 2 o 3 : 0 to 10%, the transition temperature of the glass is 300 to 340°C, and the coefficient of thermal expansion is 135 to 180×10 -7 / °C, the disadvantage of this glass is that Tl 2 The toxicity of O is very high. At the same time, the thermal expansion coefficient of glass is relatively large, so it cannot be used for sealing with medium and low expansion coefficients.

[0011] Hitachi Manufacturing Co., Ltd. has announced a vanadium oxide (V 2 o 5 ) is solder glass, the sealing temperature is less than 400°C, and the coefficient of thermal expansion is 90×10 -7 / °C, but in this glass, lead oxide is a necessary component, which cannot meet the requirements of lead-free. At the same time, it also contains highly toxic thallium oxide