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单体液压支柱(以下简称单柱)是煤矿高档普采的主要支护设备,它具有安全、可靠、成本低、使用维护方便等优点。自90年代以来全国每年的需求量都在80万套左右。80年代中期之前,单柱活柱筒均采用电镀铜锡合金套硬铬进行防腐。尽管铬层的硬度很高,但在矿井下的潮湿环境中易脱落,使用寿命短。据调查,国产单柱活柱筒使用几个月后镀层即出现局部脱落、基体腐蚀。镀层的寿命一般只有一年左右,其原因是铬本身虽耐腐蚀,但镀层的孔隙率较高,水和其它液体可通过小孔穿过镀层到达基体。由于铬的电极电位比铁高,
Single hydraulic prop (hereinafter referred to as the single column) is the main supporting equipment for high-grade general mining in coal mines. It has the advantages of safety, reliability, low cost and convenient use and maintenance. The annual demand of the country has been around 800,000 since the 1990s. Before the mid-1980s, single-cylinder column are made of electroplated copper-tin alloy hard chromium corrosion. Despite the high hardness of the chromium layer, it is easy to fall off in the wet environment under the mine and has a short service life. According to the survey, after a few months of using a single-column live cylinder made locally, the coating is partially peeled off and the substrate is corroded. The life of the coating is generally only about a year, the reason is that although the corrosion resistance of chromium itself, but the coating porosity is high, water and other liquids through the coating through the coating to reach the substrate. As the chromium electrode potential higher than iron,