US Patent,  title: Method of forming an alkali metal-doped calcium-SiA1ON material, inventors:  Abbas Saeed Hakeem, Qasem Ahmed Qasem Drmosh, Natalia Anna Wójcik, Sharafat Ali, Amar Kamal Mohamedkhair, Assignee: KING FAHD UNIVERSITY OF PETROLEUM AND MINERALS (Dhahran), Date of Patent: Nov 22, 2022

A method of forming an alkali metal-doped calcium-SiAlON material is provided. The method includes mixing calcium-SiAlON powder and an alkali metal hydroxide to form a reaction mixture. The mixture further includes spark plasma sintering (SPS) the reaction mixture at 800 to 940 degrees Celsius (° C.) to form the alkali metal-doped calcium-SiAlON material. The alkali metal hydroxide is present in an amount of 0.1 to 10 weight percentage (wt. %), based on a total weight of the reaction mixture.