Corrosion and Corrosion Inhibition of Aluminum Alloys A5052 and A5754 in Sulfuric Acid Solutions by Some Inorganic Inhibitors (2024)

FAQs

What is the corrosion inhibitor for Sulphuric acid? ›

The corrosion of metal surfaces by aqueous sulfuric acid is inhibited by incorporating into the latter a phosphorus compound having a phosphorus atom linked to an unshared oxygen atom.

A few commonly used inorganic inhibitors are chromates, borates, nitrates, nitrites, phosphates, and silicates.

Hydrochloric acid is one of the most widely used agents in the industrial sector and it corrodes metals such as aluminum. As such, there is a need to use inhibitors for retardation of the metal dissolution process [3].

Aluminum Alloys: Corrosion

Intergranular corrosion (Fig. 2) occurs when metal on or adjacent to grain boundaries dissolves, or corrodes preferentially to grain interiors. The grain boundary region acts as an anode with the grain interior being a cathode, forming a galvanic cell (see schematic in Fig.

In general, the process of evaluation and selection of corrosion inhibitors involves three steps: (1) laboratory evaluation, (2) evaluation of compatibility (including cost), and (3) field evaluation.

Corrosion Inhibitors

In general, a weak volatile acid or base that easily hydrolyzes provides the most effective inhibition. Volatile alkaline compounds such as octadecylamine and morphine are introduced in boilers with steam to inhibit corrosion in condenser tubes by neutralizing the acidic carbon dioxide.

Painting, anodizing or any surface treatment that forms a coating on the aluminium surface will protect the surface from pitting attack. In applications when you want to preserve the aluminium look and still have a surface resistant to pitting, a clear coat or thin anodic coating would be suitable surface treatments.

Anodizing tends to be the finishing process of choice for aluminum parts. This coating can keep aluminum strong, durable, and corrosion-resistant for the long term.

Chromate conversion coatings have been extensively used due to their effectiveness in providing corrosion protection, especially for aluminum alloys. This process involves the application of chromate-containing compounds that react with the aluminum surface to form a protective layer [77].

Gallium expands when it freezes, one of the few substances to do so. A small amount of gallium will destroy anything made out of aluminum, including aluminum cans. It also attacks steel, making it very brittle.

What acid destroys aluminum? ›

Sulfuric acid dissolves aluminum metal according to the reaction: 2 Al(s) + 3 H2SO4(aq)¡Al2(SO4)3(aq) + 3 H2( g) Suppose you want to dissolve an aluminum block with a mass of 15.2 g.

Muriatic acid, otherwise known as hydrochloric acid, is a common choice for an acid wash. It is reasonably safe for the aluminum and fairly easy to come by. Keep in mind that this acid is very dangerous and should be kept away from pets and children. It is also toxic to the environment.

And aluminium oxide is impermeable. However, aluminium alloys perform differently in saltwater environments or in a saline atmosphere. In such cases, the best alloys regarding corrosion resistance belong to the 5000-series (5052, 5083, 5383, 5059) and 6000-series (6082, 6005A, 6063).

“The most practical and effective means of protecting against corrosion involves finishing surfaces with an appropriate protective coating. For aluminum alloys, the coating system usually consists of a surface to which a corrosion-inhibiting primer is applied.

Most often, testing is done by immersion in solution. Corrosive immersions may be either acidic or basic, and will last anywhere from 6 to 96 hours. Once the immersion cycle is complete, the sample is analysed by visual inspection or mass loss evaluation.

A substance that slows down / prevents a specific chemical reaction or another process by reducing the activity of a catalyst or enzyme. Inhibitors are also useful as they prevent side reactions. In the preparation of H₂SO₄ in presence of a Pt catalyst or V₂O₅, As₂​O₃​ acts as a catalytic poison/inhibitor.

1 Anodic protection systems. Anodic protection has been most extensively used to protect steel in sulfuric acid. The advantages of anodic protection are low cost, low current requirements, and applicability in aggressive acidic solutions.

An acid inhibitor is typically a modern dry powder inhibitor to thoroughly control the corrosive effects of all solid scale removers and some liquid scale removers. Acid inhibitors incorporate a unique filming agent which provides a protective coating to the metal guarding it against attack by the acid.

The most commonly used mixed inhibitors are silicates and phospates used in domestic water softeners to prevent the formation of rust water. VCI are compounds being transported in a closed environment to the site of corrosion by the process of volatilization from a source.