English to Portuguese Tech/Engineering Metallurgy / Casting coating

The plasma spray process generates enough heat to melt ceramic powder particles, enabling the application of much harder coatings like chrome oxide. But hardness is not the only factor in wear resistance, and ceramics have some shortcomings that limit their usefulness. First of all, they can only be applied up to 0.040" thick. This means they typically cannot be reground when worn, which can be done 3 or 4 times with thicker coatings. Secondly, their high hardness inherently makes them very brittle. High carbon wires, hard stainless wires, and any accidental impact can all cause the ceramic coatings to break up. When not exposed to forces that will cause brittle failure, ceramics last 4-5 times longer than metalizing. They work well on blocks drawing smaller diameter wires (especially welding wire), and they are also useful for coating pulleys, sheaves, and rollers.