Low-temperature Sintering And Properties For Aluminoborosilicate Glass/AlN Composite Materials

In this paper,AlN/glass composite materials were prepared by low temperature sintering,using AlN as raw material,CaO-Al₂O₃-B₂O₃-SiO₂-CaF2?CABSF?and CaO-Al₂O₃-B₂O₃-SiO₂?CABS?as sintering additives for having low temperature sintering range of 750-850?.The effects of glass content,AlN particle size,sintering temperature and Al₂O₃ additive on the sintering densification behavior were studied by vacuum sintering method.The dielectric properties and thermal properties of the composites were analyzed.The Sintering mechanism of AlN/glass composites was investigated.The contents and results are as follows:?1?CABSF/AlN composites were prepared by low temperature sintering with CABSF glass as sintering additive.The effects of sintering temperature,CABSF glass addition and AlN particle size on the low temperature sintering of CABSF/AlN composites were studied.AlN/60wt% CABSF composites had high relative density under 800? vacuum sintering condition.When the content of CABSF is less than 60wt%,the open porosity and the Dielectric loss increases with the CABSF content decreasing,the dielectric constant decreases with the CABSF content decreasing.A large number of pores were formed in the vacuum conditions when the 70wt% CABSF glass was added.The particle size of aluminum nitride affects the properties of glass/AlN composites.When the particle size of aluminum nitride is 2um,the obtained AlN/60wt% CABSF composites get the excellent comprehensive properties for the dielectric constant of 5.261,the dielectric loss of7.239×10^-3,thermal conductivity of 2.46W/mK,thermal expansion coefficient of matching silicon.?2?CABS/AlN composites were prepared by low temperature sintering with CABS glass as sintering additive.The effect of CABS glass on the CABSF/AlN composites was studied.The sintered properties and the dielectric loss of the CABS glass/AlN composites increased with the increase of CABS glass content.The dielectric constant decreased with the increase of CABS glass content.Under the 800? vacuum sintering condition,the obtained AlN/60wt% CABS composites get the excellent comprehensive properties for the dielectric constant of 3.95,dielectric loss of 7.026×10^-3,thermal conductivity of 2.1W/m.K.?3?In order to improve the sintered properties of aluminoborosilicate glass/Al N composites,the effect of Al₂O₃ additive on the low temperature sintering of glass/Al N composites was studied.When the content was 5wt%,the optimum sintered property ofAlN?5um?/60wt%CABSF/Al₂O₃ composites were achieved.The sintered properties of AlN?2um?/60wt%CABSF/Al₂O₃ composites increased first and then decreased with Al₂O₃ content increasing.When the Al₂O₃ content was 2wt%,the sintered property improved.AlN?2um?/60wt% CABS/Al₂O₃ composites increased first and then decreased with Al₂O₃ content increasing.When the Al₂O₃ content was 2wt%,the sintered property improved.In addition,the addition of Al₂O₃ is contributed to improve the dielectric properties of glass/AlN composites.With the increase of Al₂O₃ addition,the porosity of AlN/60wt%aluminoborosilicate glass/Al₂O₃ composites is increased,and the dielectric loss is gradually reduced.?4?In this paper,non-reactive liquid phase sintering was considered to be the dominant mechanism in aluminoborosilicate glass/AlN system.The thermal conductivity of aluminoborosilicate glass/AlN composites is influenced by AlN content and densification.The thermal conductivity of the composites mainly shows the thermal property of amorphous materials.However,the thermal conductivity of AlN is also reflected in the composites.