57results about How to "Controllable coefficient of thermal expansion" patented technology

The invention relates to a silicon carbide and silicon particle reinforced aluminum-copper based composite material and a preparation method thereof, and belongs to the field of the particle reinforced metal based composite material. The composite material is composed of the components by the weight percentage: 15-25 wt.% of silicon carbide, 45-50 wt.% of silicon and 25-40wt.% of an aluminum-copper alloy; the silicon carbide and silicon particles as a reinforcement phase are uniformly distributed in the aluminum-copper alloy matrix, and the aluminum-copper alloy matrix forms a three-dimensional reticular structure. A powder metallurgy method is used for preparation. The obtained aluminum based composite material has uniform structure, is fully dense, has the comprehensive performance of light weight, low expansion, high modulus, high strength, resistance to space radiation environment, easy processing and the like, is suitable for use in space environments, and can be used as related component materials in the aviation and aerospace fields.

The invention relates to a vanadate-system lead-free low temperature sealing glass material and a preparation method thereof. The components of the sealing glass material by mol percentage are as follows: 25 percent to 55 percent of V2O5, 5 percent to 20 percent of B2O3, 5 percent to15 percent of ZnO, 20 percent to 50 percent of TeO2 and 2 percent to 15 percent of an alkali metal oxide R2O. The preparation method of the invention comprises the steps that vanadium pentoxide, boric acid, zinc oxide, tellurium dioxide and alkali metal carbonate are adopted as raw materials; the weight percentages of the raw materials are calculated according to the mol percentage of each component of the sealing glass; the raw materials are then weighted and evenly mixed to be placed in a corundum crucible and fused under the temperature of 800 to 900 DEG C; molten glass is then cast for formation or ground into powder after being treated with water quenching and the powder is then filtered by a 200-meshsieve. The sealing glass material of the invention contains no toxic and harmful substances such as lead, cadmium, thallium, and the like, and has the advantages of low temperature for sealing, the minimum temperature reaching 300 DEG C, and good chemical stability, and is especially applicable to the sealing of electronic components.

The invention discloses a sol soaked glass wrapped layer soft magnetism composite material and a preparation method thereof and relates to a soft magnetic material and a preparation method thereof. By means of the sol soaked glass wrapped layer soft magnetism composite material and the preparation method thereof, the problems that thermal expansion coefficients of inorganic insulating layers and magnetic powder are large in difference, and the thermal expansion coefficients of inorganic insulating layers are invariable are solved. The sol soaked glass wrapped layer soft magnetism composite material is composed of magnetic powder, a silica layer wrapped with magnetic powder, a glass layer wrapped outside the silica layer and a glass sol infiltration layer. The preparation method includes: 1, pretreating the magnetic powder; 2, wrapping the silica layer on the surface of the magnetic powder; 3, wrapping the glass layer outside the silica layer; 4, preparing a blank of soft magnetic composite materials; 5, performing infiltration on the blank of the soft magnetic composite materials through glass sol; and 6, preparing the soft magnetic materials.

The invention discloses an easy-to-clean milky white glaze suitable for low-expansion ceramics. The raw materials are composed of: petalite feldspar 45-55wt%, kaolin 4-7wt%, high-temperature low-expansion frit 25-35wt%, high-temperature transparent frit Block 5-15wt%, silicon micropowder 0-10wt%, glaze stabilizer 3-6wt%. In addition, the preparation method and application of the above-mentioned easy-to-clean milky white glaze suitable for low-expansion ceramics are also disclosed. The formula system of the invention has a relatively large melting temperature range under the condition of an oxidizing atmosphere, effectively solves defects such as holes in the glaze surface, and achieves the purpose of easy cleaning while having good stability. The preparation method of the present invention is based on the general daily-use ceramic glaze and the production process of daily-use ceramics. It is suitable for various low-expansion ceramic bodies, and especially provides prerequisites for low-expansion ceramic pots used in conjunction with electrical appliances. It can promote the technological progress and application development of the low expansion ceramic industry.

The invention belongs to the technical field of composite materials, and specifically relates to a SiC / Al2(WO4)3 / Al composite material with an adjustable thermal expansion. Al is used as a matrix; a low thermal expansion material SiC is used as a reinforcement; meanwhile, a certain amount of Al2(WO4)3 powder is added in for achieving a reduction of the thermal expansion coefficient. Al2(WO4)3 is a negative thermal expansion material that is able to resist a high temperature and is stable in property. On one aspect, Al2(WO4)3 is added in for reducing the thermal expansion coefficient of the original SiC / Al composite material; on the other aspect, Al2(WO4)3 is added in for reducing the content of the highly hard abrasive SiC and increasing the subsequent processing performance of the composite material. The SiC / Al2(WO4)3 / Al composite material with the adjustable thermal expansion is prepared by a powder metallurgy technology. The thermal expansion coefficient of the SiC / Al2(WO4)3 / Al composite material is significantly lower than that of the SiC / Al composite material. Accordingly, the requirement to the thermal expansion coefficient of electronic packaging materials is met better.