Two types of low carbon MgO - C refractories with 6% graphite were prepared using microporous magnesiarich spinel （5 - 3 and 3 - 1 mm ） and fused magnesia （5 - 3 and 3 - 1 mm ） as coarse aggregates, respectively, ...Two types of low carbon MgO - C refractories with 6% graphite were prepared using microporous magnesiarich spinel （5 - 3 and 3 - 1 mm ） and fused magnesia （5 - 3 and 3 - 1 mm ） as coarse aggregates, respectively, fused magnesia （ ≤1 mm） as fine aggregate, magnesia powder （≤ 0. 088 mm ） , flake graphite powder （ ≤0. 088 mm）, metal Al powder （ 〈0. 074 mm） as matrix, and phenol resin as binder. After curing at 220 ℃ and coke-embedded firing at 1 500 ℃ , the apparent porosity, cold crushing strength, cold modulus of rupture, permanent linear change on heating, thermal shock resistance and slag resistance of the specimens were studied comparatively. The results indicate that： （ 1 ） after curing at 220 ℃ and coke-embedded firing at 1 500 ℃, the specimen with microporous magnesia-rich spinel replacing fused magnesia has lower bulk density and higher apparent porosity than the common low car- bon MgO - C specimen. After curing at 220 ℃, the specimen with microporous aggregate has lower strength than common low carbon MgO - C specimen, but after coke-embedded firing at 1 500℃, it has higher strength and lower permanent linear change on heating; （2） low carbon MgO - C specimen using microporous magnesia-rich spinel to replace fused magnesia aggregate has better thermal shock resistance but worse slag resistance.展开更多
With the increasing integration level of modern electronics,thermal management becomes an urgent issue for guaranteeing the work efficiency and lifespan of electronics.On the basis of intrinsic high thermal conductivi...With the increasing integration level of modern electronics,thermal management becomes an urgent issue for guaranteeing the work efficiency and lifespan of electronics.On the basis of intrinsic high thermal conductivity nature,highly ordered graphite and copper stripes are densely aligned in the silicone gel pads in vertical(VCuGr)and oblique(@15°CuGr)directions to couple the high thermal conductivity and mechanical softness.The wetting nature of liquid metal(LM)on the chemically treated Cu surface is utilized to form a LM layer on the two surfaces of thermal pads.The obtained LM-pad TIMs possessed ultrahigh through-plane thermal conductivity(VCuGr:71.4 W/(m K),@15°CuGr:62.5 W/(m K))under the normal packaging pressure.The thermal resistance decreased from 0.69 cm^(2) K/W to 0.25 cm^(2) K/W with the surface modification with LM.Theoretical simulation and practical thermal dissipation test results further demonstrate the excellent thermal management capability of these composites in high-power electronics.展开更多
文摘Two types of low carbon MgO - C refractories with 6% graphite were prepared using microporous magnesiarich spinel （5 - 3 and 3 - 1 mm ） and fused magnesia （5 - 3 and 3 - 1 mm ） as coarse aggregates, respectively, fused magnesia （ ≤1 mm） as fine aggregate, magnesia powder （≤ 0. 088 mm ） , flake graphite powder （ ≤0. 088 mm）, metal Al powder （ 〈0. 074 mm） as matrix, and phenol resin as binder. After curing at 220 ℃ and coke-embedded firing at 1 500 ℃ , the apparent porosity, cold crushing strength, cold modulus of rupture, permanent linear change on heating, thermal shock resistance and slag resistance of the specimens were studied comparatively. The results indicate that： （ 1 ） after curing at 220 ℃ and coke-embedded firing at 1 500 ℃, the specimen with microporous magnesia-rich spinel replacing fused magnesia has lower bulk density and higher apparent porosity than the common low car- bon MgO - C specimen. After curing at 220 ℃, the specimen with microporous aggregate has lower strength than common low carbon MgO - C specimen, but after coke-embedded firing at 1 500℃, it has higher strength and lower permanent linear change on heating; （2） low carbon MgO - C specimen using microporous magnesia-rich spinel to replace fused magnesia aggregate has better thermal shock resistance but worse slag resistance.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.11204097 and U1530120).
文摘With the increasing integration level of modern electronics,thermal management becomes an urgent issue for guaranteeing the work efficiency and lifespan of electronics.On the basis of intrinsic high thermal conductivity nature,highly ordered graphite and copper stripes are densely aligned in the silicone gel pads in vertical(VCuGr)and oblique(@15°CuGr)directions to couple the high thermal conductivity and mechanical softness.The wetting nature of liquid metal(LM)on the chemically treated Cu surface is utilized to form a LM layer on the two surfaces of thermal pads.The obtained LM-pad TIMs possessed ultrahigh through-plane thermal conductivity(VCuGr:71.4 W/(m K),@15°CuGr:62.5 W/(m K))under the normal packaging pressure.The thermal resistance decreased from 0.69 cm^(2) K/W to 0.25 cm^(2) K/W with the surface modification with LM.Theoretical simulation and practical thermal dissipation test results further demonstrate the excellent thermal management capability of these composites in high-power electronics.
