Rational Design of Electrospun Nanofibers for Gas Purification: Principles, Opportunities, and Challenges

In order to meet the sealing demands of SiC heat exchanger, the Ni-Mo filler alloy was designed, prepared and employed to braze SiC ceramics. Wetting behavior of the Ni-Mo filler alloy on SiC ceramics and interfacial microstructure of the brazed joints were systematically characterized using optical observation furnace and XRD, SEM, EDS, TEM, respectively. Flexural strengths of the brazed joints at room temperature and high temperature were measured with four-point flexural strength method. HCl immersion test was performed to evaluate the corrosion resistance of the joints. The Ni-Mo filler alloy exhibited excellent wettability on SiC ceramics. During the process of brazing, SiC reacted with element Ni of the Ni-Mo filler alloy, resulting in the formation of Ni2Si + graphite reaction layer adjacent to the SiC substrate. Ni3Mo3C and Ni2Si compounds were precipitated at the center of brazing seam. When the brazing temperature increased from 1250 ℃ to 1400 ℃, the thickness of Ni2Si + graphite layer increased gradually. The maximum room-temperature flexural strength of 174 ± 33 MPa was obtained when brazed at 1300 ℃ for 40 min. The joints also exhibited stable high-temperature strength and acid corrosion resistance. When the test temperature was 700 ℃, 800 ℃, 900 ℃, the joints gave the strength retention rate of 92.5 %, 79.8 %, 67.2 %, respectively. It was believed that the formation of high melting point phases played an important role. Residual strength of the joints after HCl corrosion exceeded 130 MPa, revealing a good potential for applications in corrosion environment.

Joining of SiC ceramics using the Ni-Mo filler alloy for heat exchanger applications

Atomic simulation of textured silicon carbide surface ultra-precision polishing

Latecomer firms' combination of strategies in a specialized suppliers sector: A comparative case study of the Korean plastic injection molding machine industry

Interaction of Yb2Si2O7 environmental barrier coating material with Calcium-Ferrum-Alumina-Silicate (CFAS) at high temperature

This article is a detailed review of the measures to modify the high-temperature mechanical properties of silicon carbide ceramic matrix composites (SiC CMCs), namely toughness, high-temperature stability and wear resistance Additionally, it briefly describes the common processing methods of the SiC CMCs and their application in the high-temperature field of aerospace The advantages and disadvantages of various existing processing and molding methods for the SiC CMCs are also discussed The high-temperature mechanical properties of the SiC CMCs are mainly affected by the properties of the matrix, added phase and interface It is crucial to reduce the crystal defects of the matrix and select a suitable enhancement phase for an elevated performance Moreover, it is important to improve the bonding at the interface between the enhancement phase and the matrix This review is expected to provide useful information for the subsequent development of complex SiC CMCs for high-temperature applications

Advances in modifications and high-temperature applications of silicon carbide ceramic matrix composites in aerospace: A focused review

Development of internal circulation two-platen IMM for thermoplastic polymer

A differential molding system for micro injection molding of thermoplastics was designed and fabricated. As the core part, a planetary gear pump was integrated into the molding module and used for metering, delivering and supercharging. The molding system was installed in the stationary platen beside which a servo motor was connected to the transmission shaft of the pump through a coupling. A traditional injection molding machine which was equipped with this module could be upgraded to a precise micro injection molding machine and realized the function of multiple micro injection molding machines. A process study was first performed to verify the machine performance and to determine the influence of the main process parameters. It has been proved by experiments that the differential molding system could realize the manufacture of fine and precision parts with micro structures in one step with high efficiency at low cost.

Differential Molding System for Micro Injection Molding of Thermoplastics

The invention provides a coaxial 3D printing process and equipment, which are used for printing different coaxial fuse wires of inner and outer materials through coaxial nozzles According to the process, the outer layer is a main use layer and determines the mechanical performance of a product; the inner layer for extruding wire materials is an assistant forming layer, the section of the extrudedouter layer annular material is prevented from collapsing; the assistant forming layer can be made of a material with relatively small relative volume density or a material which can be removed later; the outer layer is a performance guarantee layer, the section of a coaxial wire material can be similar to an annulus during performance analysis, and the strength of a product with an annular section is better than that of a product with a round section when the section areas are the same according to theoretically mechanic analysis, so that the strength of the product manufactured by the process and equipment under the situation that weight is not changed, and further light weight of 3D printing technology can be realized The process and equipment can be used for optimizing product performance, such as fire-proof products, anticorrosive products and performance enhanced products to meet the requirement of different use conditions, so that the application range of 3D printed products can be expanded

Wang Xiulei

Papers

Advances in modifications and high-temperature applications of silicon carbide ceramic matrix composites in aerospace: A focused review

Development of internal circulation two-platen IMM for thermoplastic polymer

Differential Molding System for Micro Injection Molding of Thermoplastics

Coaxial 3D printing process and equipment

The mechanism of the controlled deposition of electrospun fibers