30results about How to "Reduce thermal mismatch stress" patented technology

The invention discloses a full-silicon MEMS wafer-level vacuum packaging method based on anode bonding; two-time anode bonding is adopted in the MEMS wafer-level vacuum packaging process to realize mechanical and electric signal connection among a cover plate, an MEMS device structure and a substrate and form a pressure controllable MEMS sealing cavity; compared with the existing full-silicon bonding process based on silicon-silicon solder bonding and silicon-silicon fusion bonding, the method in the invention is low in process difficulty and high in rate of finished products; the cover plateglass sheet is thinned to 10-50 microns and the substrate glass sheet is thinned to 10 -50 microns; the thickness of the dielectric layer of the existing full-silicon bonding process is not more than3 microns to the maximum; the thinner dielectric layer is, the larger the introduced parasitic capacitance is; hence, the parasitic capacitance introduced by the method in the invention is small, so that the signal-to-noise ratio output by the MEMS device is improved.

The invention relates to the technical field of composite materials, and specifically discloses a high-temperature ceramic coating YSZ-RETaO 4 The SiC-based composite material and its preparation method, weigh aluminum oxide, aluminum hydroxide, aluminum dihydrogen phosphate and calcium oxide, ball mill with absolute ethanol, mix evenly, dry and then sieve; pass the sieved powder SiC The substrate is embedded in an alumina ceramic boat and calcined at a high temperature to form a transition layer on the surface of the SiC substrate; YSZ and RETaO are coated by atmospheric plasma spraying 4 The powder is sprayed onto the surface of the transition layer to form a SiC composite material sprayed with a ceramic coating on the surface. The thermal conductivity of the silicon carbide-based composite material prepared in this patent is 0.67-0.82W·m ‑1 ·K ‑1 Between, to meet the use environment of ultra-high temperature 2200 ~ 2500 ℃.

The invention provides an YSZ-rare earth zirconate thermal barrier coating of a gradient structure and a preparation method thereof. The coating material comprises an adhesive layer, an 8YSZ-rare earth zirconate gradient layer and a surface layer. The 8YSZ-rare earth zirconate material has relatively low conductivity, high-temperature sintering resistance and excellent resistance to heat shocks, and also can prevent oxygen from entering the adhesive layer on active service to alleviate oxidization of the adhesive layer to form TGO. The heat mismatching stress of the material can be reduced bymeans of an optimized design of the gradient structure, so that the heat stability of the whole material member is improved; the surface layer is a CMAS corrosion layer, so that the problem that an existing YSZ coating is corroded by CMAS can be alleviated. As Pd or a oxide ceramic layer is adopted, CMAS molten at a high temperature is not wet in the surface layer, and the rolling angle is small,and CMAS is hardly attached to the surface of the coating, so that CMAS corrosion is avoided.

A preparation method of a low-expansion zirconium tungstate / aluminum composite material, relating to a low-expansion ZrW 2 O 8 / Al composite material preparation method. In order to solve the problem of excessive γ‑ZrW content in the zirconium tungstate / Al composite prepared by the existing method 2 O 8 This leads to the problem of a large thermal expansion coefficient of the composite material. Method: Weigh ZrW by volume fraction 2 O 8 powder and aluminum matrix; ZrW 2 O 8 The powder is placed in a molding die and pre-compressed, then sintered at high temperature and quenched to obtain ZrW 2 O 8 Preforms, impregnated with liquid aluminium. In the low-expansion zirconium tungstate / Al composite material prepared by the invention, the aluminum matrix and ZrW 2 O 8 The particles all have a continuous structure, which reduces the γ‑ZrW in the as-cast zirconium tungstate / Al composites 2 O 8 content. The internal stress is reduced by stress relief annealing treatment, thereby reducing the thermal expansion coefficient of zirconium tungstate / Al composites. The invention is suitable for preparing zirconium tungstate / aluminum composite material.

The invention belongs to the technical field of manufacturing of group-III nitride thin films and devices and provides an indium gallium nitride thin film on a flexible transparent polyimide substrateand a preparation method of the indium gallium nitride thin film. Polyimide is taken as a substrate and a first In<x>Ga<1-x>N buffer layer, a graphene layer, a one-dimensional nano-conductive material layer, a second In<x>Ga<1-x>N buffer layer and an In<x>Ga<1-x>N epitaxial layer are sequentially prepared on one side surface of the polyimide substrate from inside to outside, wherein the first In<x>Ga<1-x>N buffer layer, the second In<x>Ga<1-x>N buffer layer and the In<x>Ga<1-x>N epitaxial layer all are prepared by using an electron cyclotron resonance-plasma enhanced metal organic chemical vapor deposition method at low temperature; and the graphene layer and the one-dimensional nano-conductive material layer are prepared by using a spin coating method, so that the prepared high-quality In<x>Ga<1-x>N thin film can be used for preparing flexible transparent devices, such as an indium gallium nitride-based solar cell and a thin-film transistor and has a broad application prospect.

The disclosed non-polar composite GaN-based substrate comprises overlays between the substrate and the GaN extension layer reflection / ohm / stress buffer layer. Wherein, the preparation method for the substrate comprises: on the growth substrate, growing middle medium layer (or crystal kernel) and the non-polar first GaN-based extension layer in turn; overlaying the mask layer; etching the mask to form the GaN window and mask layer strip; growing the non-polar second GaN extension layer; overlaying the reflection / ohm / stress buffer layer; bonding substrate; peeling the substrate, medium layer, the first extension layer, mask strip, and the part with hole on the second extension layer; exposing other part of the second extension layer for thermal treatment.

The invention discloses a filling material for manufacturing a layered electromagnetic thin film material swelling sample and a method for preparing the filling material, and provides a method for adopting the filling material to manufacture the layered electromagnetic thin film material swelling sample. The method includes the steps that firstly, a through hole is machined in a silicon dioxide substrate through a precision micromachining method; the through hole is filled with a specially-made mixing material, and metallographic phase polishing processing is conducted on the through hole; the surface of the substrate is plated with an annular bottom electrode through an ion sputtering method, a ferroelectric thin film and a ferromagnetic thin film are sequentially deposited through a sol-gel method, annealing is conducted, and an annular top electrode is deposited on the surfaces of the thin films after being cleaned and dried; acetone analytical reagents and a sodium hydroxide solution are used for corrosion to remove the filling material in the through hole, an independently-supported thin film window is formed, and then the electromagnetic thin film swelling sample suitable for a swelling test is obtained. The method is easy and convenient to operate and high in manufacturing efficiency, and the manufacturing method of the layered electromagnetic thin film material swelling sample is suitable for the swelling test.

The disclosed processing steps for a conductive non-polar composite GaN substrate comprise: on the growth substrate, growing middle medium layer (or crystal kernel) and the non-polar first GaN-based extension layer in turn; overlaying the mask layer to etch and form the GaN window and mask layer strip; growing the non-polar second GaN extension layer; overlaying the conductive reflection / ohm / stress buffer layer; bonding substrate; then, peeling the substrate, medium layer, the first extension layer, mask strip, and the part with hole on the second extension layer for thermal treatment.

The invention discloses a metal workpiece double layer coating suitable for high temperature environment and a manufacturing method thereof. The manufacturing method of the metal workpiece double layer coating suitable for the high temperature environment includes the following steps of 1) pretreatment: degreasing the surface of a metal workpiece, sandblasting roughening and cleaning; 2) spraying:preheating the pretreated metal workpiece, adopting an atmospheric plasma spraying device for spraying, first spraying a ceramic inner layer on the surface of the metal workpiece, then heating and spraying a metal outer layer and then spraying a metal layer on the side of an obtained coating; 3) heat treatment: conducting vacuum heat treatment on the sprayed metal workpiece and conducting gas quenching. According to the manufacturing method, the metal layer is sprayed on the ceramic layer. On one hand, the high cost of ceramic precision machining is reduced; on the other hand, various corrosion-resistant or wear-resistant alloy materials can be applied. In addition, the melting point of metal is lower than that of the ceramic, and the mechanical properties of the coating can be changed bythe heat treatment process.