Cobalt-based alloy powders are commonly used in plasma transfer arc welding (PTAW) due to their excellent high-temperature properties and resistance to wear and corrosion. These alloys are typically composed of cobalt as the base metal, with various alloying elements such as chromium, tungsten, nickel, and carbon added to enhance specific properties. Co Powder,Cobalt 6 Powder,Cobalt 12 Powder,Cobalt 21 Powder Luoyang Golden Egret Geotools Co., Ltd , https://www.xtcwelding.com
The use of cobalt-based alloy powders in PTAW offers several advantages, including:
1. High-temperature strength: Cobalt-based alloys exhibit excellent strength and resistance to deformation at elevated temperatures, making them suitable for welding applications that involve high heat.
2. Wear resistance: These alloys have a high hardness and resistance to wear, making them ideal for welding applications where the welded parts are subjected to abrasive or erosive conditions.
3. Corrosion resistance: Cobalt-based alloys offer good resistance to corrosion, making them suitable for welding applications in aggressive environments, such as those involving chemicals or saltwater.
4. Thermal conductivity: Cobalt-based alloys have good thermal conductivity, allowing for efficient heat transfer during welding and reducing the risk of heat-affected zone (HAZ) defects.
5. Compatibility with other materials: Cobalt-based alloys can be easily welded to a wide range of base metals, including stainless steels, nickel alloys, and other cobalt-based alloys, providing versatility in welding applications.
To use cobalt-based alloy powders for PTAW, the powder is typically fed into the plasma arc using a powder feeder. The powder is then melted by the high-temperature plasma arc and deposited onto the workpiece, forming a weld bead. The specific welding parameters, such as arc current, travel speed, and powder feed rate, will depend on the specific alloy and application requirements.
It is important to note that the selection of the cobalt-based alloy powder should be based on the specific welding application and the desired properties of the final weld. Different cobalt-based a
Atmosphere Makes New Breakthrough in Atmospheric Peroxy Radical Measurement Technology
ã€Instrument Development of China Instrument Network】 Recently, the Research Group of Anguang Institute of Researcher Zhang Weijun has made a breakthrough in the measurement of atmospheric peroxy radicals by chemical amplification. Related research results have been achieved by removing the water vapor interference in peroxy radical chemical amplification with a large diameter. The Nafion dryer was published in the Analytical Chemistry (a zone) organized by the American Chemical Society.
Variation of RO2 Concentration in Primary Pollution Process in Actual Atmospheric Observation
Peroxy radicals (RO2) play an important role in the degradation of atmospheric volatile organic compounds (VOCs) and the formation of ozone (O3) and secondary organic aerosols (SOA), with low atmospheric concentrations and strong activity. Measurement is difficult. Chemical amplification is one of the most important methods for measuring RO2 in the atmosphere. It converts low concentrations of RO2 into high concentrations of NO2 through chain-type cyclic reactions to achieve an amplified measurement of RO2, but the actual atmospheric background (such as O3, NO2) The influence of water vapor, etc., limits the sensitivity and accuracy of RO2 measurements. The research team effectively eliminated the influence of O3, NO2, etc. on the measurement through the dual-channel wideband cavity enhanced absorption spectroscopy technology developed in the early stage, and realized the detection limit of peroxy radical 0.9pptv at 60s sampling time. However, the influence of water vapor on the reaction chain length (water effect) has always been an insurmountable problem in chemical amplification, which limits the application of chemical amplification in the actual atmosphere.
Researcher Zhao Weixiong and Yang Chengqiang et al. proposed a dual-channel atmospheric peroxy radical measurement technique based on Nafion tube injection. This not only reduces the RO2 sample loss, but also effectively avoids the high relative humidity that affects the reaction chain length. influences. At present, the instrument has been used in practical observation experiments in laboratories and the PRD field and will play an important role in the study of atmospheric chemistry mechanisms.
The research work was supported by the National Natural Science Foundation of China, the National Key Research and Development Program of the Ministry of Science and Technology, the Chinese Academy of Sciences Green Promotion Association and the Anhui Outstanding Youth Fund. At present, the technology and device have applied for national invention patent protection CN200810053909.1.
(Original Title: Achievers New Breakthrough in Atmospheric Peroxy Radical Measurement Technology)