30results about How to "Reduce growth stress" patented technology

The invention relates to a control method for eliminating a spot defect of a moderately thick plate and belongs to the technical field of metallurgy. The method comprises the following steps of (1) a heating stage: carrying out high pressure water phosphorus removal after heating a continuous cast slab through controlling a heating coefficient; (2) a rolling stage: carrying out multi-pass high pressure water phosphorus removal in a hot rolling process; and (3) a cooling stage: cooling a hot rolled plate in an ultrafast cooling and laminar cooling combined way to prepare the moderately thick plate. Through the control on the temperature and the atmosphere in the heating stage, the matching of the rolling temperature and a phosphorus removal process in the rolling process and the combination of the ultrafast cooling and laminar cooling ways in the cooling stage in the control method disclosed by the invention, the straightness of an iron oxide scale and an interface is obviously increased; and no residual iron oxide scales are remained on the surface of a steel plate through subsequent sand blasting and shot blasting, so that the generation of the spot defect is effectively inhibited, and the surface quality of the moderately thick plate is obviously improved.

The invention relates to the field of diamond manufacturing, in particular to a diamond growth tray and system. A diamond growth tray, comprising a base and a platform mounted on the base; the platform is in the shape of a regular polygonal prism or a circular truncated shape, and has a groove on the upper surface, and the edge of the opening of the groove is inverted corner design. Compared with the existing technology, it has the following effects: through the newly designed seed crystal tray, the plasma distribution and electric field distribution on the surface of the seed crystal can be maintained in the best state, ensuring a stable growth environment for the diamond seed crystal, reducing the number of surface growth defects, Finally, a high-quality single crystal diamond sheet is synthesized; through the newly designed seed tray, the growth rate of impurities such as carbon black on the edge of the seed tray can be significantly reduced, ensuring a longer stable growth time for a single time, and thicker diamonds can be grown at one time products and improve production efficiency.

The invention provides a method and device for growing silicon carbide crystal by PVT method. The method includes: (1) an assembly stage; (2) a heating stage: the assembled crucible is placed in a furnace body, and the crucible is heated, The temperature difference between the temperature at the center of the top of the crucible and the edge of the top of the crucible is controlled to be ΔT1; (3) Crystal growth stage: keep the temperature at the center of the top of the crucible unchanged, control the heat preservation cover to move up along the side wall of the heat preservation cylinder, and control the center of the top of the crucible at the same time. The temperature difference between the temperature of the crucible and the top edge of the crucible is reduced to ΔT2, so that the silicon carbide raw material gas phase is transferred to the seed crystal for crystal growth. By controlling the upward movement of the heat preservation cover, the annular temperature field is more uniform and stable, and the radial temperature gradient gradually decreases to ΔT2, realizing the directional quantitative adjustment of the radial temperature gradient, gradually reducing the radial temperature gradient at the seed crystal, and reducing the size of the silicon carbide. The difference between the minimum thickness of the center and the edge of the crystal increases the effective utilization of the same weight of silicon carbide crystal.

The invention discloses a double-layer thermal barrier / high-temperature low-infrared emissivity integrated coating. The coating is a multi-layer superimposed structure, and the multi-layer superimposed structure sequentially includes a metal bonding layer and a thermal barrier ceramic from the inside to the outside. Inner layer, thermal barrier ceramic outer layer and low infrared emissivity layer, the thermal barrier ceramic inner layer is La 2 Zr 2 o 7 ‑8YSZ mixture layer, where La 2 Zr 2 o 7 The powder accounts for no more than 45% of the mass fraction of the mixture, the outer layer of the thermal barrier ceramic is a rare earth zirconate layer, and the low infrared emissivity layer is a Bi 2 o 3 ‑Al 2 o 3 -ZrO 2 ‑CaO‑SiO 2 Department of glass coating. The invention also provides a coated metal composite material and a preparation method thereof. The integrated coating of the invention has the characteristics of heat insulation performance, low infrared emissivity at high temperature, excellent thermal shock resistance and the like.

The invention discloses a manufacturing method of a light-emitting diode epitaxial wafer and the light-emitting diode epitaxial wafer, and belongs to the field of light-emitting diodes. The method comprises the steps as follows: a substrate is provided; and a low-temperature buffer layer, a high-temperature buffer layer, an N-type layer, an active layer, an electron blocking layer and a P-type layer sequentially grow on the substrate. The manufacturing method is characterized in that the P-type layer grows as follows: a first GaN sub-layer with a first thickness and a first Mg doping concentration grows on the electron blocking layer at a first growth temperature, a first growth pressure and a first growth rate; a second GaN sub-layer with a second thickness and a second Mg doping concentration grows on the first GaN sub-layer at a second growth temperature, a second growth pressure and a second growth rate; and a third GaN sub-layer with a third thickness and a third Mg doping concentration grows on the second GaN sub-layer at a third growth temperature, a third growth pressure and a third growth rate.