Corrosion of Copper Alloys in Consumer Electronics Environments
C Results of corrosion testing on eight alloys from five copper alloy families common in the consumer electronics industry—copper nickel tin (CuNiSn), copper beryllium (CuBe), copper titanium (CuTi), phosphor bronze (CuSnP), and Corson alloys (CuNiSiX)—are presented. Short-term exposures were conducted in simulated consumer environments such as a salted carbonated cola beverage, artificial human perspiration, and phosphate-buffered saline. Longer-term, conventional salt fog testing, up to 1,000 h, was also conducted. In all of these tests, CuNiSn showed the lowest corrosion rate followed closely by CuBe alloys. Corrosion rates of CuTi alloys were consistently the highest after shortterm testing, while CuSnP showed the highest corrosion rate after salt fog testing.
Corrosion Behaviors of Supersaturated and Peak-Aged CuNiSiCr Alloys under Salt Spray Environment
As promising substitutes for Cu-Be alloys, Cu-Ni-Si series alloys have been investigated intensively concerning their mechanical and electrical properties but without much attention on their corrosion performance. Herein corrosion behaviors and mechanisms of the supersaturated and peak-aged CuNiSiCr alloys are investigated using salt spray test, x-ray diffraction, scanning and transmission electron microscopes. The corrosion rate of the aged sample is lower than that of the supersaturated one due to forming a denser protective corrosion product, Cu2O. Theoretical analyses indicate that the Cu2O film grows by oxidization of the matrix and its granular size is greatly influenced by the precipitates. The second corrosion product Cu2(OH)3Cl/CuCl2·3Cu(OH)2 forms by consuming the oxide Cu2O, which will induce pitting and deteriorate the corrosion resistance. Based on the obtained results, guidance concerning the composition and treatment optimization is provided for enhancing the anti-corrosion capability of the CuNiSiCr alloys.
Recycling of silicon powder waste cut by a diamond-wire saw through laser-assisted vacuum smelting
Abstract This paper proposes laser granulating technology for recycling harmful silicon powder waste cut by a diamond-wire saw. The silicon block produced by laser was easily melted in a traditional vacuum smelting furnace to form a silicon ingot with a high yield and filling rate, which could reach up to 94.7% and 65.7%, respectively. The removal efficiency of the carbon contamination was 74.2% during laser melting process and reached 86% after 30 min of vacuum smelting. In addition, laser melting process promoted the removal of most metal impurities, such as Al, Na, Ca, Mg, and so on, in the silicon powder waste without introducing any other impurities. The residual impurities could be further removed by vacuum smelting. The experiment revealed that the out capacity of the silicon block melted by a single laser gun was 1.91 kg/h, the energy consumption of laser melting was 2.63 kWh/kg, and the yield of the silicon block exceeded 97% at a laser power of 2000 W, a laser scanning interval of 5 mm, and a scanning speed of 6 mm/s. Therefore, the proposed approach is one of the most simple and efficient silicon powder waste pretreatment methods.