A New Corrosion-Resistant Ni-Mo-Cr Alloy for the Most Versatile Environments

Corrosion-resistant nickel alloys are vital to the chemical process industries.  They are known to be significantly more resistant than stainless steels to the key chemicals such as hydrochloric and sulfuric acids.  Even though the Ni-Cr-Mo alloys possess an excellent corrosion performance there has always been a need for materials with improved resistance to these two mineral acids without the drawbacks of the Ni-Mo materials.  These drawbacks are mainly related to their intolerance to dissolved oxygen and oxidizing chemicals, and these Ni-Mo alloys are much less stable metallurgically than the Ni-Cr-Mo alloys.  To fill in this gap, a new Ni-Mo-Cr alloy was recently developed and it is known commercially as HYBRID-BC1^® alloy. This paper will provide new comparative corrosion data between the new HYBRID-BC1 alloy and several Ni-Cr-Mo and Ni-Mo materials in a variety of environments, mainly in hydrochloric and sulfuric acids, with a special emphasis on the effects of oxidizing chemicals in the acids.
Key words:  HYBRID-BC1 alloy, Ni-Cr-Mo, Ni-Mo, Ni-Mo-Cr, iso-corrosion diagrams, hydrochloric acid, sulfuric acid, dissolved oxygen, ferric ions, and cupric ions