Nickel-based corrosion-resistant alloy
The main alloying elements are copper, chromium and molybdenum. It has good comprehensive performance and can resist various acid corrosion and stress corrosion. The earliest application (produced in the United States in 1905) was nickel-copper (Ni-Cu) alloy, also known as Monel alloy (Monel alloy Ni 70 Cu30); in addition, there is nickel-chromium (Ni-Cr) alloy (that is, nickel-based heat-resistant alloy , hot corrosion-resistant alloys among corrosion-resistant alloys), nickel-molybdenum (Ni-Mo) alloys (mainly refers to Hastelloy B series, domestic professional corrosion-resistant alloy manufacturers include Beijing Iron and Steel Research Institute, Shanghai Kangsheng Special Alloy Co., Ltd. companies, Beijing Rongpin Technology Co., Ltd., Baoti Group Rare Metal Materials Co., Ltd., etc.), nickel-chromium-molybdenum (Ni-Cr-Mo) alloy (mainly refers to Hastelloy C series, domestic professional corrosion-resistant alloy manufacturers include Beijing Iron and Steel Research Institute, Beijing Rongpin Technology Co., Ltd., Baoti Group Rare Metal Materials Co., Ltd., etc.). At the same time, pure nickel is also a typical representative of nickel-based corrosion-resistant alloys. These nickel-based corrosion-resistant alloys are mainly used to manufacture parts for various corrosion-resistant environments such as petroleum, chemical industry, electric power, etc.
Category Nickel-based corrosion-resistant alloys mostly have an austenitic structure. In the solid solution and aging treatment state, there are intermetallic phases and metal carbonitrides on the austenite matrix and grain boundaries of the alloy. Various corrosion-resistant alloys are classified according to their composition and their characteristics are as follows:
The corrosion resistance of Ni-Cu alloy is better than that of nickel in reducing media, and its corrosion resistance is better than copper in oxidizing media. It is resistant to high temperature fluorine gas, hydrogen fluoride and hydrogen fluoride in the absence of oxygen and oxidant. The best material for acids (see Metal Corrosion).
Ni-Cr alloy is a nickel-based heat-resistant alloy; it is mainly used under oxidizing media conditions. Resistant to high temperature oxidation and corrosion from gases containing sulfur, vanadium and other gases, its corrosion resistance increases with the increase in chromium content. This type of alloy also has good resistance to hydroxide (such as NaOH, KOH) corrosion and stress corrosion resistance.
Ni-Mo alloy is mainly used under conditions of reducing medium corrosion. It is the best alloy to resist hydrochloric acid corrosion, but in the presence of oxygen and oxidants, the corrosion resistance will decrease significantly.
Ni-Cr-Mo(W) alloy has the properties of the above-mentioned Ni-Cr alloy and Ni-Mo alloy. Mainly used under oxidation-reduction mixed media conditions. This type of alloy has good corrosion resistance in high-temperature hydrogen fluoride gas, in hydrochloric acid and hydrofluoric acid solutions containing oxygen and oxidants, and in wet chlorine gas at room temperature.
Ni-Cr-Mo-Cu alloy is resistant to both nitric acid and sulfuric acid corrosion, and also has good corrosion resistance in some oxidation-reduction mixed acids.
