Bismuthate low-melting point and lead-free sealing grass and preparation method thereof

Abstract

The present invention discloses a bismuthate low-melting point and lead-free sealing grass and a preparation method thereof. The bismuthate low-melting point and lead-free sealing grass powder comprises, by mass, 75-90% of base glass and 10-25% of a filler, wherein the filler is a zirconium phosphate salt with an expansion coefficient of -5*10<-6>k<-1>-5*10<-6>k<-1>. The bismuthate low-melting point and lead-free sealing grass of the present invention has characteristics of lead-free property and green environmental protection, can replace the lead-containing glass so as to eliminate the pollution due to the lead, and has excellent chemical stability. The production process is simple and the cost is low. Compared to other filler-doped sealing glass powders, the sealing temperature of the present invention is low, the glass transition temperature of the present invention is 330-370 DEG C, the softening temperature of the present invention is 370-410 DEG C, the sealing temperature of the present invention is less than 450 DEG C. With adjusting the proportion of the filler, the adjustable expansion coefficient can be realized at the low sealing temperature, wherein the adjustment range is (70-90)*10<-7>/DEG C, such that different requirements of the sealing device to the expansion coefficient of the sealing material can be met, and the sealing for VFD, PDP, CRT and other glass products can be directly performed.

Description

technical field [0001] The invention belongs to the field of sealing glass powder and its preparation method, in particular to a lead-free low-melting-point glass which can be used for sealing VFD, PDP, CRT and other glass products and its preparation method. Background technique [0002] Sealing glass is an advanced welding material, which can connect and seal the same or different materials. The materials that can be sealed include metal, ceramics and special glass, and are widely used in electric vacuum and microelectronics technology, Laser and infrared technology, high energy physics, energy, aerospace, automobile and many other fields. In recent years, with the development of microelectronic technology, electronic display technology and optoelectronic technology, the performance and process requirements of sealing products are getting higher and higher. [0003] Electronic displays such as vacuum fluorescent displays, plasma displays, and cathode ray tubes all need to...

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Problems solved by technology

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, and the price of thallium is relatively expensive. Therefore, this glass and the glass made of it Glass powder is neither environmentally friendly nor economical, and can only be used on special vacuum glass products

Chinese patent CN1807312A reports a V 2 o 5 -B 2 o 3 -ZnO-based glass powder, the sealing temperature is lower than 530°C, but the glass powder still contains toxic V 2 o 5 , and V 2 o 5 It is a semiconductor material with high electrical conductivity after melting into glass, which has a negative impact on the insulation performance of the sealed device

CN1372532A is SiO 2 -B 2 o 3 -ZnO-Bi 2 o 3 It is a sealing glass, and a large amount of Li is added to the glass component 2 O, Na 2 O, K 2 O and MgO, CaO, SrO, BaO and other alkali metal and alkaline earth metal oxides, the sealing temperature is 450-650°C, and the thermal expansion coefficient is (70-130)×10 -7 / °C, the disadvantages are: (1) the glass of this system is prone to devitrification during the sealing process, (2) the fluidity of the glass is poor, (3) the strength of the glass after sealing is poor, (4) ) Due to the addition of a large amount of alkali metal ions, the conductivity of the glass is high

The glass component of CN1656033A is improved on the basis of CN1372532A. In order to improve the sealing strength of the glass, in addition to all the glass components of the former, Sc 2 o 3 , Y 2 o 3 , La 2 o 3 , CeO 2 、Pr 2 o 3 、Nd 2 o 3 、Sm 2 o 3 、Eu 2 o 3 、Gd 2 o 3 , Tb 2 o 3 、Dy 2 o 3 、Ho 2 o 3 、Er 2 o 3 、Tm 2 o 3 and Lu 2 o 3 At least one of the rare earth oxides; the sealing temperature of the glass system is between 450 and 650 ° C, and the thermal expansion coefficient of the sealing glass can be reduced to (60 ~ 80) × 10 by adding fillers -7 / °C; but due to the addition of a certain amount of rare earth oxides to improve the sealing strength of the glass, the glass-forming performance of the glass is reduced

Korean patent KR20060097667A discloses a Bi 2 o 3 -B 2 o 3 -Sb 2 o 3 It is a bismuth salt sealing glass material, the sealing temperature is 440-460°C, and the thermal expansion coefficient can be reduced to (71.4-80)×10 by adding fillers -7 / °C, but its disadvantage is that the crystallization rate during the sealing process is difficult to control

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