Recent Research Experience

Multicomponent Equimolar Oxide Ceramics
•    Synthesis and phase stability studies on multicomponent equimolar (aka high entropy) oxide ceramics.

Thermal Barrier Coatings for Gas Turbines
•    New materials for thermal barrier coatings
•    Effect of rare-earth (RE) stabilisers on the thermal stability and fracture toughness of TBC materials;
•    Mechanism of molten salt (sulphate-vanadate) attack on RE-stabilised zirconia TBC materials;

Environmental Barrier Coatings for SiC Based High Temperature Ceramics
•    Development of coatings of yttrium silicates and ytterbium silicates
•    Thermodynamic understanding of phase formation in yttria-silica system

Ceramic Composites for High Temperature Aerospace Aplications
•    Oxidation behaviour of SiCf-SiC composites in high velocity combustion gases.
•    Composites of SiC with MoSi2 and ZrB2 as reinforcements have been developed. Their mechanical properties, electrical conductivity and oxidation behaviour have been studied.

Ceramic Matrices for High Level Waste Immbobilisation
Synthetic rock (synroc) based crystalline matrix for high level waste immobilisation are being studied. 

Nanocrystalline Alumina Coatings
Alumina coatings on stainless steel were deposited by thermal spray and their dry sliding wear resistance was studied.
 

Nanostructured Titania Films for Self-Cleaning Applications
Nanostructured titania films were developed using sol-gel technique. Self-cleaning properties were evaluated.

Glasses and Amorphous Materials

Glass-forming Ability of Metallic Systems: Thermodynamic criteria for glass-forming ability of iron-base and copper-base alloys were developed. Experiments using ball milling and rapid solidification were carried out to check the validity of thermodynamic calculations.

Alumina based glasses stabilised by rare earth oxides:
Alumina with up to three oxide additions for stabilising the amorphous phase (Y2O3, La2O3, TiO2).

Solid Oxide Fuel Cells

Nano-structured SOFC Anodes: Chemical synthesis is used for developing nano-structured NiO-YSZ and NiO-YbSZ materials. The main result is that nanometric precipitates of NiO have been formed in stabilised zirconia through metastable solid solution and precipitation. The powders have high surface area, with potential for making efficient anodes for intermediate temperature SOFC’s.

 

Conducting ceramic coatings on interconnects for prevention of chromium poisoning

Post-Doctoral Research
Processing and Phase Selection in Oxide Ceramics: Ionic conducting phases in TiO2-YO3/2-ZrO2 system were studied in terms of thermodynamics of metastability and kinetics of phase transformations at high temperatures. Ionic conductivity was measured in collaboration with California Institute of Technology.
Chemical precursor synthesis of ZrO2-based thermal barrier coating (TBC) materials, TiO2-YO3/2-ZrO2 based ionic conducting materials, and metastable solid solutions in YAG. A novel plasma spraying technique was developed in collaboration with SUNY - Stony Brook, by combining reverse co-precipitation and liquid precursor plasma spraying.
Thermal Barrier Coatings – Deposition and Basic Studies: Growth of multi-material multi-layered thermal barrier coatings (TBC’s) during EBPVD, using TEM, FIB, SEM and XRD. 
High temperature performance evaluation of TBC’s. Topics include thermochemical compatibility of Gd2Zr2O7 and ZrO2-YO1.5 bi-layered TBC; high temperature phase stability in rare-earth doped zirconia; mechanism of inter-mixed zone formation in TBC systems (collaboration with University of Pittsburgh).
Failure mechanisms of TBC’s, using fracture toughness and high temperature experiments on plasticity of zirconia TBC’s (related to erosion and foreign object damage).
Morphological stability and sintering resistance of high temperature coatings by surface diffusion experiments based on AFM characterisation of grain boundary grooving.
Related Experience: Collaborations with other research groups, writing reports and research proposals, active mentoring of Ph.D. students and interns, assistance in advanced level teaching.

Doctoral Research
High pressure consolidation technique was developed for processing Al2O3 based bulk metastable amorphous ceramics. 
Discovery of large-scale plasticity in amorphous ZrO2-Al2O3.
Vacuum hot press installation, operation and maintenance of a conventional vacuum hot-press.
Advanced ceramic matrix composites processing.
Mentoring of M.E. students and interns; organisation of symposia, student seminar series, and social events.

Masters Research
Contact-less processing of ceramics: Development of an aerodynamic levitation method for up to 2200˚C; 
Rapid solidification studies on Al2O3-BaO system using the levitation apparatus.

Bachelors Research
Strain rate sensitivity of AISI 304 stainless steel in relation to sheet metal formability.