Phase transformations on the surface of YAG composite ceramics under the action of directed laser treatment

• Published in: Applied surface science 2016-07, Vol.377, p.416-425
• Main Authors: Vlasova, M., Márquez Aguilar, P.A., Escobar Martinez, A., Kakazey, M., Guardian Tapia, R., Trujillo Estrada, A.
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Ceramics; Crystallites; Fitting of gaussian curves; Irradiation; Lasers; Phase composition; Phase transformation; Surface laser treatment; Surface layer; Texture; Y3Al5O12 ceramics
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2016.03.139

[Display omitted] •During directed laser treatment of the surface of the composite ceramics consisting of predominantly Y3Al5O12 and Al2O3, the oriented crystallization of YAG and Al2O3 takes place.•As a result of high-temperature heating, in the surface layer of tracks, the partial dissociation of Y3Al5O12, Y2Ti2O7, and Al2Y4O9 and enrichment in YAlO3 occur.•The content of YAlO3, the size of YAG crystallites, and their crystallographic texturing depend on the irradiation mode.•After laser treatment, the ceramic material transforms into a three-layer macrostructure consisting of the basic ceramic material, near-surface textured layer, and surface layer. The laser treatment of composite ceramics based on Y3Al5O12 with Y2Ti2O7, Al2Y4O9, and Al2O3 additives is accompanied by the melting of the surface layer and formation of tracks. In the volume of tracks, the partial dissociation of Y3Al5O12, Y2Ti2O7, and Al2Y4O9, and the formation of new phases such as YAlO3 of orthorhombic and hexagonal modifications along with the appearance of additional content of Y3Al5O12 and Al2O3 are observed. The content of all these phases depends on the irradiation mode and the phase composition of the ceramics. With increase in the corundum content in ceramic specimens, in the tracks, the Al2O3 content increases, and the Y3Al5O12 content decreases. In the volume of tracks, Y3Al5O12 crystallites are textured. The size of YAG crystallites and their crystallographic texturing depend on the irradiation mode and Y3Al5O12/Al2O3 phase ratio. On the surface of tracks, a layer enriched in YAlO3 forms. Thus, as a result of laser treatment, on the surface of the ceramics, a two-layer coating with a radically new phase composition and specific texture of Y3Al5O12 crystallites forms.