Processing of a glass ceramic surface by selective focused beam laser treatment

The results presented shows that Sr-fresnoïte glass ceramics layers can be processed by applying a two stage process: first the melting of a glass powder to form a dense amorphous layer; then the crystallisation of this layer. However, the microstructures resulting of a crystallisation step performed by mean of a one-scan laser treatment are heterogeneous. IR camera analysis highlights that this heterogeneity is due to thermal profile strongly depending on the position on the scanned surface. Moreover, the high energy scanning conditions required to promote crystallisation make that this later takes place on cooling after surface has been re-melted. Processing by a multi-scan mode (numerous successive rapid scans) seem more suitable. In that case, IR camera analysis shows a homogeneous thermal state of the surface. Additional investigations have to be performed in order to be able to master the relation between the thermal profile and the laser scan parameters.