What is the Difference Between Hard Anodised and Cast Iron

The key difference between hard anodised and cast iron is that hard anodized iron offers non-stick surfaces, whereas cast iron offers durable, inexpensive, and evenly heating metal surfaces.

Iron is a very important metal in industries and in manufacturing different metallic objects such as cookware. Hard anodized iron and cast iron are often used as cookware metals due to their useful properties.

CONTENTS

1. Overview and Key Difference
2. What is Hard Anodised Iron
3. What is Cast Iron
4. Hard Anodised vs Cast Iron in Tabular Form
5. Summary – Hard Anodised vs Cast Iron 

What is Hard Anodised Iron?

Hard anodised iron is made with an electrolytic process that is useful in increasing the thickness of the natural oxide layer on the surfaces of metal parts. It is an electrolytic passivation process. We call it an anodizing process because, in this process, we treat the metal part as the anode electrode of an electrolytic cell. This process is very important because it can increase the resistance to corrosion and wear. Also, it provides better adhesion for paint primers and glues. Moreover, we can use anodic films in several cosmetic effects along with thick, porous coatings (which are able to absorb dyes with thin transparent coatings) that can add reflected light wave interference effect.

Typically, the anodizing process can change the texture (microscopic) of the surface of the metal part and the crystal structure of the metal that is near the surface. Normally, the thick coatings obtained from this method are porous. In that case, we need to use a sealing step to get corrosion resistance. E.g. anodized aluminum surfaces are harder than normal aluminum metal surfaces, but we need to use sealing agents to protect them from corrosion.

What is Cast Iron?

Cast iron is an alloy of iron that we can readily cast in a mould. It is hard and relatively brittle. It contains iron, carbon, silicon, and manganese, along with trace amounts of sulfur and phosphorous as well. The amount of carbon in this alloy is very high compared to steel. In addition, it has a considerable amount of silicon (1-3%) so, it is actually an alloy of iron-carbon-silicon. Moreover, it has a relatively low melting temperature than other iron alloys.

This alloy solidifies as a heterogeneous alloy. It is not that ductile; thus, it is not suitable for rolling. Apart from that, it does not react with the moulding material when melted and poured. The major reason for the usefulness of this alloy is its low melting point. This low melting point causes good fluidity, castability, excellent machinability, resistance to deformation, and wear resistance.

There are several types of cast iron according to the microstructure of the alloy. These types are as follows:

• Grey cast iron
• Ductile cast iron
• Malleable cast iron
• White cast iron

We use cast iron for engineering and construction structures because of its stability. Therefore, it is useful in pipes, machines, and automotive industry parts, such as cylinder heads (declining usage), cylinder blocks, and gearbox cases. Moreover, it is resistant to destruction via oxidation.

What is the Difference Between Hard Anodised and Cast Iron?

Iron is a very important metal in industries and in manufacturing different metallic objects such as cookware. Hard anodized iron and cast iron are two important applications of iron metal. The key difference between hard anodised and cast iron is that hard anodized iron offers non-stick surfaces, whereas cast iron offers durable, inexpensive, and evenly heating metal surfaces.

The following figure summarizes the difference between hard anodised and cast iron in tabular form.

Summary – Hard Anodised vs Cast Iron

Hard anodised iron and cast iron are very important in producing cookware. The key difference between hard anodised and cast iron is that hard anodized iron offers non-stick surfaces, whereas cast iron offers durable, inexpensive, and evenly heating metal surfaces.

Reference:

1. “Which Cookware Best Suits You –  Cast Iron or Hard Anodized?” Kitchen Infinity, 3 Oct. 2021.

Image Courtesy:

1. “Cheap carabiners” By User:Polyparadigm – Own work (Public Domain) via Commons Wikimedia
2. “Cast-iron-pan” (CC0) via Pixabay