A Brief History of Thermal Spray Technology

The Flame Spray Process (defined as the process of melting materials in a heating zone and propelling them in a molten, or heat softened condition, onto a target to form a coating) was first developed in Switzerland by Max Ulrich Schoop around 1910. It was then just referred to as Metallizing. In the first 20 years of its existence, the process was mainly used for spraying Zinc. The more substantial use of the process for spraying hard metals on machine parts began in the United States in the early 1930’s. The development of the Flame Spray Process through the 1950’s was characterized by the extensive development of materials and improvements in the process. Many new metal alloys were developed during this time, particularly for use in Hard Facing and the spraying of ceramics.

A big breakthrough in Flame Spray technology was the development of the Plasma Flame Spray Process. This development allowed the use of materials with a melting point over 5000 deg. F (the limit for oxy-acetylene). The secondary advantage of providing a controlled atmosphere for the flame has proved of equal importance. The plasma flame permits the selection of an inert gas for the flame medium so that chemical reaction such as oxidation, during the heating and application of the spray material, can be controlled.

In the early 1980’s, the term Flame Spray was generally replaced by the term Thermal Spray. This was deemed to better describe all of the available coating systems that had been developed over the years.

Recent advances in technologies have further enhanced both the equipment and materials available. Industrial robots are now commonly used for the application process, allowing for very uniform "as sprayed coatings" on part configurations where this is desirable.

Also a High Velocity Oxy-Fuel material is now available that can replace chrome plating.

It is best to remember that while you can slow down the effects of wear, you can’t stop it forever. Parts will eventually lose dimensionality and must be replaced or resurfaced using thermal spray coatings. The ability to apply coatings across a broad range of thickness, finish and composition requirements makes thermal spray an ideal way to protect components from being discarded prematurely.