6results about How to "Increase nucleation density" patented technology

According to the silicon carbide / diamond multi-layer composite film and the preparation method thereof, a polycrystalline silicon carbide matrix in the multi-layer composite film is a bottom layer, and the multi-layer composite film has high strength, high rigidity, high heat conductivity and oxidation resistance; the components of the gradient SiC-C transition layer gradually change from pure SiC to rich C-SiC and then to diamond-like carbon, and the gradient SiC-C transition layer is used for slowly releasing thermal stress and enhancing binding force; the nanocrystalline diamond is used as the top layer and has high hardness, low friction coefficient, particle scouring resistance and high infrared transmittance; the silicon carbide / diamond multi-layer composite film is obtained through a chemical vapor deposition method, the process is mature, and the silicon carbide / diamond multi-layer composite film has good heat conduction performance and infrared transmittance and is suitable for infrared guidance systems with extremely severe working environments, such as optical materials of fairings, optical windows and the like.

This invention proposes a Zr-based membrane for separating benzene / cyclohexane and its preparation method. The Zr-based membrane includes Zr-BDC membranes, Zr-BDC-PAA, or Zr-BDC-PVA. A polymer is introduced into the Zr-BDC framework via a secondary growth method to improve the membrane's selectivity for separating benzene / cyclohexane. The Zr-based membrane is directly synthesized using an in-situ growth method, which is simple in process. By adjusting the membrane growth time, good benzene / cyclohexane separation performance is achieved. Zr-BDC-PAA or Zr-BDC-PVA membranes are organic-inorganic hybrid membranes. The addition of polymers can adjust the membrane's pore structure, enhance its polarity, improve the size selectivity for separating benzene / cyclohexane, promote the intercalation of the Zr-BDC membrane, and influence the membrane thickness to some extent. The Zr-BDC membrane, by adjusting the growth time, grows more densely and continuously, thus exhibiting good benzene / cyclohexane separation performance.

The application discloses a preparation process of a lead zirconate titanate (PZT) film layer, a film layer structure and application thereof, and relates to the technical field of piezoelectric material film layer preparation. The preparation process comprises the following steps: S1, forming a low tensile stress silicon nitride layer on the surface of a substrate, which is used for homogenizing the in-plane stress gradient of a wafer; and S2, forming a piezoelectric functional layer on the surface of the silicon nitride layer in a sputtering mode, wherein the piezoelectric thin film material of the piezoelectric functional layer is lead zirconate titanate (PZT). The film layer structure and the preparation process thereof adopt the silicon nitride layer to relieve the thermal mismatch stress of the piezoelectric functional layer system, can improve the piezoelectric constant e31 of the central region of the wafer, and improve the uniformity of the whole wafer.

The application relates to the field of high polymer foaming materials, and particularly discloses a preparation method of elastic polypropylene composite foaming beads, the foaming beads and a molded product thereof, and the preparation method of the elastic polypropylene composite foaming beads comprises the following steps: uniformly mixing polypropylene resin, alpha-olefin elastomer and an additive, melt plasticizing, the ratio of the melt mass flow rate of the polypropylene resin to that of the alpha-olefin elastomer being 1:1-3, to obtain a composite; injecting a supercritical fluid, the supercritical fluid accounting for 0.5-3.0 wt% of the total mass of the composite, mixing and melting to obtain a mixed melt; gradiently cooling the mixed melt, then extruding, cutting and drying, then adding a dispersion medium and a foaming agent, impregnating through pressurization and heating, then releasing pressure to foam, washing, drying and curing, to obtain the foaming beads; the molded product is obtained by water vapor heating molding of the foaming beads; and the foaming beads have the advantages of good compatibility and dispersibility, good heat resistance, high expansion ratio, high elasticity and dimensional stability.

This invention relates to the field of N-type crystalline silicon solar cell manufacturing technology, specifically to a graded deposition LPCVD process for N-type cell passivation layers. The main steps include depositing a silicon-oxygen tunneling layer of 1.5–2.5 nm and graded deposition of the film layers. The graded deposition steps include: a first-stage deposition to obtain a polycrystalline silicon film of 90–150 nm with a crystallinity of 80–95%; a second-stage deposition to obtain a polycrystalline silicon film of 50–100 nm with a crystallinity of 60–80%; and a third-stage deposition to obtain a polycrystalline silicon film of 30–80 nm with a crystallinity ≤50%. This invention achieves polycrystalline silicon films with crystallization gradient characteristics by changing process parameters, such as pressure, temperature, and gas flow rate ratio, within the same deposition process. The crystallinity of polycrystalline silicon significantly affects the diffusion behavior of impurity atoms subsequently doped using methods such as boron diffusion and phosphorus diffusion. This technology can optimize film performance, meet specific process application requirements, and further improve cell performance.

The application discloses a method for preparing a GaN thin film on a diamond substrate, and comprises the following steps: growing a GaN nanocolumn on a conventional substrate, growing a polycrystalline diamond thin film on the GaN nanocolumn, removing the conventional substrate, taking the polycrystalline diamond thin film as a substrate, taking the GaN nanocolumn on the polycrystalline diamond thin film as a nucleation layer, and growing a GaN thin film on the nucleation layer. The application utilizes the GaN nanocolumn based on the diamond substrate to form the nucleation layer, takes the grown diamond thin film as the substrate, removes the silicon, integrates the GaN nanocolumn on the diamond thin film, takes the GaN nanocolumn as an intermediate layer to grow the GaN thin film, and can greatly relieve the stress generated by the lattice mismatch between the GaN and the diamond substrate, can avoid the stress and the lattice orientation problem of the diamond substrate directly epitaxial GaN thin film, is favorable to the uniformity of the diamond thin film, and improves the nucleation density. Therefore, the high-quality GaN thin film is obtained.