Avoid pipe subjected to soil, air and transport medium (oil, natural gas) corrosion protection technology. Most of the pipes conveying oil and gas in the soil environment, the transmission medium is corrosive, and pipe inner wall and the outer walls are likely to corrode. Once the pipe is corrosion, resulting in leakage of oil, gas, not only disrupted transport and pollution of the environment, and may even cause fires, harm. According to the United States pipeline industry statistics in 1975 due to corrosion caused a direct loss of $600 million. Therefore, to prevent pipe corrosion is the important content of the pipeline project.