Cairo University

MTPR Journal

 

CHARACTERISTICS of METAL SURFACES COATED by THERMAL SPRAYING and LASER COATING

2016-12-17
Sameh Akila1, M. A. Hafez1, M. Atta Khedr1, Ali S. Khalil2
1- Department of Laser Sciences and Interaction National Institute of
Laser Sciences, Cairo University, Giza, Egypt.
2- Institute of mineral Education, Tebin, Helwan, Cairo, Egypt

Vol./Issue: 16 , id: 199

Two ways had been used for obtaining coating of Nickel – 5%Aluminum as a bond coat followed by Magnesia-Stabilized Zirconium Oxide(ZrO2-18 to 25%MgO), Calcia-Stabilized Zirconium Oxide(ZrO2 -5%CaO) and mix from them as a top coat on the surfaces of Stainless Steel 304 (S.S. 304) specimens; were Thermal Spraying and Laser coating. The Thermal spraying coating was done by Air/Atmospheric plasma spraying APS using a PLASMA-TECHNIK AG Switzerland and F4-MB (machine-plasma torch), however CW 1.06 μm Nd-YAG diode pumped laser with maximum output power 2200W has been used for laser coating/cladding LC. The microstructure and mechanical properties of both coatings were investigated by scanning electron microscopy, X-ray diffraction, wear resistance and microhardness tests. The measurements showed the preference of the laser coating/cladding over the thermal spraying coating; where the internal microstructure showed more homogeneity of LC than APS coatings, The LC process involved complete melting of the coating powder in the laser generated melt pool followed by rapid solidification. The hardness of the coating layer was approximately 1600 Hv compared with only 400 Hv for the APS coating.