Preparation And Properties Of Metallized Al₂O₃ Ceramics

Ceramic metallization is a combination of high strength,high hardness,acid and alkali resistance,corrosion resistance,insulation and electrical and thermal conductivity of metal materials,and easy soldering and packaging.Ceramic metallization devices are used in aerospace and microelectronics packaging.,Biomedicine,chemical industry,metallurgy,vacuum electronics,new energy fields have been widely used.The density,porosity and glass phase content of the ceramic substrate,and the wettability and thermal expansion coefficient of the substrate and the metallization layer have an important influence on the performance of the ceramic metallization product.This paper discusses the effect of Al2O3 ceramic substrates with different densities,porosity,and glass phase content on the microstructure,mechanical properties,and gas tightness of the metallized samples,and discusses the related mechanisms of ceramic metallization,and then designs and prepares different The thermal expansion coefficient of the ceramic substrate and the metallization layer,combined with the experimental results,initially clarified the matching principle of the thermal expansion coefficient of the ceramic substrate and the metallization layer,and realized the effective adjustment of the thermal expansion coefficient of the ceramic and metallization formula.The main findings are as follows:（1）The effects of different additives on the mechanical prop erties of Al₂O₃ceramics were discussed.Mg O mainly forms a liquid phase with Al ₂O₃ to promote sintering densification;Ti O₂ mainly forms a replacement solid solution with Al ₂O₃ to reduce the sintering temperature;3Y-Zr O₂ mainly improves the strength of Al₂O₃ by phase transformation and toughening,in which 95%with 1%Ti O ₂%Al₂O₃ ceramic has a strength of 331MPa and the best performance.（2）Porosity and glass phase content have a great influence on the mechanical properties of Al₂O₃ ceramic matrix.The 95%Al₂O₃ ceramic with a porosity of 0.77%has the highest bending resistance,reaching 330MPa.When the glass phase of the ceramic is 1.0 vol%,99%Al₂O₃ ceramic has the highest bending resistance,reaching376MPa.（3）The increase in the porosity of the ceramic matrix is beneficial to the diffusion of the manganese-containing glass phase from the metallized layer to the Al ₂O₃ matrix.At the same time,the higher porosity can provide more space to"absorb"the diffused manganese-containing glass phase;When the ceramic matrix has similar porosity and pore size,the diffusion behavior of the manganese-containing glass phase is mainly affected by the glass phase content in the matrix.The higher the glass phase content,the longer the diffusion path of the manganese-containing glass phase,which is beneficial to the sample resistance For the improvement of tensile strength,when the content of the glass phase in the ceramic matrix is 9.5 vol%（G-9.5-M）,the porosity is0.86%,and the tensile strength of the metallized sample reaches 10035N.（4）During the metallization process,the capillary force caused by the pore size of the matrix is the main driving force for the diffusion of the manganese-containing glass phase,and the porosity of the matrix will a ffect the"absorption"of the matrix to the manganese-containing glass phase.The glass phase content will affect the diffusion depth of the manganese-containing glass phase in the matrix.The result of the interaction of these three factors is the evoluti on of the microstructure and mechanical properties of the metallized specimen.（5）The theoretical value of the thermal expansion coefficient of the ceramic substrate and the metallization layer calculated by the modified Turner model formula is close to the experimental value.This formula can provide a reference for predicting the thermal expansion coefficient of the ceramic substrate and designing the metallization layer formula;from the metal According to the results of chemical experiments,when the difference between the thermal expansion coefficients of the ceramic substrate and the metallization layer is（0.01～0.42）×10^-6/℃,the matching between the substrate and the metallization layer is high,and the bending resistance of the ceramic after metallization increases by 66%,from 1200N to In 1990N,the tensile force between ceramic and metal reached 9499N.