Research On Lead-free Solder Sealing Process Of Vacuum Glass-ceramics

Vacuum glass is an excellent transparent thermal insulation material,with excellent thermal insulation and sound insulation performance,but it also has undeniable shortcomings,such as fragile,low toughness,large thermal expansion coefficient and so on.Because the crystal properties are better than the glass,and the glass has the advantages of manufacture easily.So people will combine the two materials,and the combination product is the glass ceramics.Glass ceramics is a new kind of material which is formed by the addition of heat treatment,which makes a large amount of uniform distribution of micro crystals(micron level)in the glass matrix.In other words,glass ceramics is a kind of material which has the property of the ceramics made by glass technology.So it has the advantages of the glass and the ceramics.Glass ceramics is a more ideal sealed glass material in twenty-first century.After sealing products can be made into a better performance of the induction cooker,used for aerospace or for home decoration panel and so on.The finished product will be widely used in civil and military industry.Although vacuum microcrystalline glass has good prospects,but its sealing process and the choice of sealing side solder have always been a difficulty for scientific research workers.Because the leaded solder has huge harm to human body and the environment,and phosphate can be made of glass,called phosphate glass,and the phosphate glass can be used as sealing solder to seal the glass.In this paper,lead-free phosphate solder is used.Microcrystalline glass vacuum furnace with high temperature melting method is adopted to improve the sealing.This method is to put microcrystalline glass and solder in the high frequency heating furnace,the furnace interior environment is steady,the glass and the solder are heated evenly,the thermal stress is relatively small,can achieve good sealing effect.The main content of this paper:(1)This paper discussed the subject background and research significance.The paper expounds the dynamic research about vacuum glass,the advantage of vacuum microcrystalline glass replace the common glass,the significance of the microcrystalline glass sealing process using the lead-free solder.(2)This paper studied and analyzed the condition of vacuum glass ceramic sealing.The thermal expansion coefficient matching between glass and solder,solder wetting effect,vacuum furnace thermal radiation,etc are included.And these are prepared for the following ANSYS and experimental analysis.(3)This paper used simulation analysis with ANSYS software,analyzing microcrystalline glass sealing,thermal stress and strain under different sealing temperature,obtaining the stress and strain distribution,biggest position and maximum stress and strain at the same time.Because the thermal stress and strain is less than glass destruction limit,the sealing process can meet the sealing requirements.(4)In this paper,the lead-free solder is used and the microstructure is analyzed by metallographic experiment,scanning electron microscopy(SEM)test,hardness test,to judge a good sealing effect under different process.Through the above experiment,it is found that the lead-free solder the best sealing temperature is 530?,the best sealing time is 150 min.