What Does Laser Glazing Mean?
Laser glazing is a surface-melting technique in which a continuous high-energy carbon dioxide laser traverses the surface of a metal part, creating a thin layer of melted material.
After the laser-glazing process, the material's surface appears glassy, hence the name laser glazing. This technique is applicable to both ceramics and metals. Laser glazing can produce surfaces that are amorphous, glassy or non-crystalline in structure.
Laser glazing can provide excellent wear resistance and enhanced corrosion resistance.
Corrosionpedia Explains Laser Glazing
Laser glazing involves melting a thin surface layer followed by rapid solidification. The resulting surface is super hard, crack free and has high lubricity, also known as "metallic glass." The thickness of this glazed layer is approximately 100 microns.
Laser glazing can potentially make thermal barrier coatings impermeable, resistant to corrosion on the surface and porous at bulk.
Laser glazing is done by scanning a high-power beam over the material surface, in order to induce melting of a thin surface layer. Because of the high rate of energy delivery, this is a very efficient method of melting material, and very little energy is wasted in heating the substrate. Because the substrate remains cold, the melted material cools very rapidly when the energy input is removed. This rapid quenching infers the desired properties on the material.
This technique produces highly corrosion- and wear-resistant surfaces. For example, laser glazing of gas flame sprayed NiCrAl, FeNiCrAl, and NiCr alloys is used to produce coatings highly resistant to hot corrosion. Laser irradiation makes it possible to glaze thin surface layers of sprayed porous coatings. The laser-modified layer of the coating possesses a new surface composition and morphology.
Similarly, in 304 stainless steel, laser glazing effects carbides at grain boundaries, thus improving resistance to stress corrosion cracking. In 614 Al bronze, it homogenizes the surface, improving its resistance to corrosion in chloride solutions. In high-speed steels it generates a uniform fine distribution of hard carbide particles which improves cutting performance.