41results about How to "Reduce residual tensile stress" patented technology

A glass laminate substrate for electronic substrates, such as flat panel displays, includes a transparent glass core bounded by transparent glass skin layers, wherein the coefficient of thermal expansion of the core is greater than the coefficient of thermal expansion of the skin layers thereby forming a residual compressive stress in the skin layers and a residual tensile stress in the core. The relative thickness of the skin layers can be selected to enhance the strength of the glass laminate substrate while maintaining a sufficiently low residual tensile stress in the core to allow scribing and separating of the substrate to size. Interlayers can be located between the core and the skin layers, wherein the interlayers include a residual compressive stress, and produce a reduced residual tensile stress in the core.

The invention provides a method for preparing a tungsten coating by using a cold air dynamic spraying technology, belonging to metal surface engineering. The method specifically comprises: preparing the tungsten coating on a copper alloy or stainless steel substrate from fine tungsten powder used as a raw material by using the cold air dynamic spraying technology. During the preparation of the tungsten coating by cold air dynamic spraying, the particle size of the tungsten powder is controlled at 0.4-10 mu m, nitrogen gas or helium gas can be used as a carrier gas and accelerating gas, and the spraying distance is controlled at 10-50 mm. When nitrogen as is used as the carrier gas and accelerating gas, the temperature of cold air dynamic spraying is controlled at 500-800 DEG C, the air flow pressure is controlled at 20-50bar, and the powder feeding amount is controlled at 10-50 g / min. When helium gas is used as the carrier gas and accelerating gas, the temperature of cold air dynamic spraying is controlled at 200-500 DEG C, the air flow pressure is controlled at 10-30bar, and the powder feeding amount is controlled at 10-20 g / min. The method provided by the invention has the advantages that: the tungsten coating can be prepared on a copper alloy and stainless steel; the prepared tungsten coating is dense, has no oxidation phenomenon existence, intact coating interface bonding and no pores, cracks and other defects; and the tungsten coating with the thickness less than 10 microns can be prepared.

The invention relates to a preparation method of a boron carbide ceramic composite material. The method includes the steps of S1, performing wet mixing on boron carbide powder, a carbon source and a mixing medium to obtain a mixed material, drying, grinding, and sieving to obtain a material for mould pressing; S2, performing compression molding on the material for mould pressing, and drying to obtain a ceramic green body; S3, placing a silicon block on the ceramic green body to perform vacuum infiltration reaction sintering so as to obtain a boron carbide ceramic composite material precursor;S4, removing the residual silicon on the surface of the boron carbide ceramic composite material precursor, performing thermal treatment on the precursor in heating equipment, and cooling to room temperature to obtain the boron carbide ceramic composite material. The preparation method can lower sintering temperature, increase the compactness of the boron carbide ceramic composite material and increase the mechanical performance of the boron carbide ceramic composite material.