Which materials have corrosion resistance?

(1) Rubber has a certain corrosion resistance, and the price is cheap. Therefore, in the case of low temperature, it is widely used in the control valves of corrosion-resistant equipment, and rubber-lined diaphragm valves were produced in the 1950s and 1960s. In order to regulate the corrosive medium with large flow rate, a butterfly valve with rubber lining was produced. But rubber is not completely corrosion-resistant, and the use temperature, pressure conditions are limited.
(2) Polytetrafluoroethylene (referred to as F4, PTFE) is the best corrosion-resistant material nowadays, known as the "king of corrosion resistance". It has excellent corrosion resistance and heat resistance, and can be used for a long time at - 250 - 250 C. Apart from the corrosive effect of fluorine and melted alkali metals at high temperature and pressure, and the slight expansion of some halides or aromatic hydrocarbons, other factors such as strong acids (including concentrated nitric acid and aqua regia), strong bases, strong oxidants, greases, ketones, ethers and alcohols do not work even at high temperatures. It can resist almost all chemical media without being corroded.
(3) Polytetrafluoroethylene propylene (PTFE) is a new material with excellent corrosion resistance and temperature resistance. It has high chemical stability and excellent chemical corrosion resistance, such as strong acid, alkali and oxidant. It also has outstanding heat and cold resistance, can be used for a long time in the temperature - 00 - 250 C environment; at the same time, it also has the characteristics of non-adhesion, non-water absorption, non-combustion and so on. In addition, the material has good fluidity and can be lined on the surface of components as corrosion resistant materials.

(4) As early as the 1920s and 1930s, corrosion-resistant alloys such as Harrington alloy and Monel alloy were available abroad, but only in the 1950s and 1960s did they start in China. The use of corrosion-resistant alloys in the field of control valves began in the 1980s, but the price of corrosion-resistant alloys is too expensive to be widely used.