I like heavier razors, so aluminum and titanium are not my metals of choice.
The two metals differ. They are both strong, Titanium has a very high natural resistance to corrosion. On the other hand, aluminum is very reactive.
However, aluminum readily reacts with oxygen to form aluminum oxide on its surface. This mineral is known as corundum. While not as hard as diamond, it is harder than any other natural mineral. It is the substance of which ruby and sapphire gemstones are made. Sapphire crystal is often used for watch faces in expensive watches as it is highly scratch resistant. Once the aluminum develops a coating of aluminum oxide, it is both scratch and chemical resistant.
There is an old story that I heard on Car Talk radio. As the story goes, a driver was caught out in a snow storm and realized that there was no snow scraper in the car. There was an aluminum can of soda in the vehicle. After drinking the soda, the driver flattened the can and used it to scrape the snow from the windshield. In the process of scraping, the windshield got scratched. How did that happen? Aluminum is softer than glass. However, once the surface of the can oxidized to form aluminum oxide, that coating is much harder than the glass windshield and could easily scratch glass. Thus there are two morals to this story: never use a soda can to scrape snow from your windshield and don't worry about the durability of your aluminum razor if you treat is with care.
The two metals differ. They are both strong, Titanium has a very high natural resistance to corrosion. On the other hand, aluminum is very reactive.
However, aluminum readily reacts with oxygen to form aluminum oxide on its surface. This mineral is known as corundum. While not as hard as diamond, it is harder than any other natural mineral. It is the substance of which ruby and sapphire gemstones are made. Sapphire crystal is often used for watch faces in expensive watches as it is highly scratch resistant. Once the aluminum develops a coating of aluminum oxide, it is both scratch and chemical resistant.
There is an old story that I heard on Car Talk radio. As the story goes, a driver was caught out in a snow storm and realized that there was no snow scraper in the car. There was an aluminum can of soda in the vehicle. After drinking the soda, the driver flattened the can and used it to scrape the snow from the windshield. In the process of scraping, the windshield got scratched. How did that happen? Aluminum is softer than glass. However, once the surface of the can oxidized to form aluminum oxide, that coating is much harder than the glass windshield and could easily scratch glass. Thus there are two morals to this story: never use a soda can to scrape snow from your windshield and don't worry about the durability of your aluminum razor if you treat is with care.