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Porous aluminum alloys produced by the metal-gas eutectic method or GASAR process need to be performed under a certain pressure of hydrogen, and to carry over melt to a tailor-made apparatus that ensures directional solidification. Hydrogen is driven out of the melt, and then the quasi-cylindrical pores normal to the solidification front are usually formed. In the research, the effects of processing parameters (saturation pressure, solidification pressure, temperature, and holding time) on the pore structure and porosity of porous aluminum alloys were analyzed. The mechanical properties of Al-Mg alloys were studied by the compressive tests, and the advantages of the porous structure were indicated. By using the GASAR method, pure aluminum, Al-3wt.%Mg, Al-6wt.%Mg and Al-35wt.%Mg alloys with oriented pores have been successfully produced under processing conditions of varying gas pressure, and the relationship between the final pore structure and the solidification pressure, as well as the influences of Mg quantity on the pore size, porosity and mechanical properties of Al-Mg alloy were investigated. The results show that a higher pressure of solidification tends to yield smaller pores in aluminum and its alloys. In the case of Al-Mg alloys, it was proved that with the increasing of Mg amount, the mechanical properties of the alloys sharply deteriorate. However, since Al-3%Mg and Al-6wt.%Mg alloys are ductile metals, their porous samples have greater compressive strength than that of the dense samples due to the existence of pores. It gives the opportunity to use them in industry at the same conditions as dense alloys with savings in weight and material consumption.

The protective coating system for port machinery is introduced. The industrial standard JT/T 733-2021 Specification of Anticorrosive Coatings for Port Machinery Steel Structureis described in terms of standard development principle and scope. Meanwhile, the items and technical indexes for the standard are interpretated. [ABSTRACT FROM AUTHOR]

In this paper, a high-performance PIN diode single-pole-double-throw (SPDT) switch for W-band application is developed. By employing quasi-monolithic millimeter-wave integrated circuit (Q-MMIC) technology, the cost of the switch is significantly reduced while maintaining performance and size with conventional MMIC counterpart. A 3-D PIN diode model is used to describe the diode characteristic under both forward and reverse biasing states. In order to alleviate parasitic parameters effect on performance of the switch, compensation structures are analyzed and adopted. The measurement results show the insertion loss is less than 2 dB from 82 to 100 GHz and the isolation is greater than 32 dB from 82 to 105 GHz. The total size of the SPDT switch is 2.1 mm × 4.3 mm. [ABSTRACT FROM PUBLISHER]