Objectives: The aim of the study was to develop a predictable controlled method for the precipitation of nano-alumina coating as a surface treatment in trial to improve zirconia /resin bonding and to determine the durability of bond between coated samples and commercially available resin cement.Material and methods: A total of 30 disc-shaped zirconia specimens were fabricated from yttrium partially stabilized pre-sintered zirconia blocks and divided into two main groups of 15 discs in each, according to the type of surface precoating. “Group I”: Polished zirconia with the Ceramill polish – lab kit. “Group II”: Zirconia treated with concentrated sulfuric acid solution. These were further subdivided into three subgroups (A, B, C) representing: control uncoated group, Surface coating of the zirconia with nano-structured alumina using aluminum nitride powder {AlN}, and using Aluminum Sulfate powder Al2(SO4)3 respectively. The coated specimens of the different groups and the hydrolyzed powder were characterized for crystalline phase identification using XRD. The coated specimens surfaces were examined using SEM for surface microstructure and AFM for surface roughness. All previously mentioned groups were bonded using the Aplicap adhesive resin cement disks (RelyX Unicem, 3M ESPE, USA) to the 30-zirconia disks. The bondability of the coatings to zirconia were qualitatively evaluated using the scotch tape. To determine the effect of mechanical testing on the strength of the adhesive junction, the shear bond strength was measured & studied for all 6 groups & subgroups. The bonded specimens were water stored for 24hrs at 37oC then tested for its shear bond strength. The mode of failure was evaluated to confirm the results of shear bond strength.Results: Mineralogical analysis of the sintered zirconia specimens from groups I, II and subgroup (A) revealed only tetragonal phase. While the coated zirconia from subgroup (B) exhibited wide peaks of nano-sized, semi-crystalline Boehmite (AlOOH) with peaks of unreacted AlN. After heat treatment of nano-boehmite to 900 oC, the aluminum oxyhydroxide lamellae were transformed to δ nano-alumina. The coated zirconia from subgroup (C) revealed same peaks of nano-boehmite only, which transformed to δ alumina by heat treatment to 900 oC. The SE micrographs confirmed better retentive surface features for (group II, subgroup B, C). The coated specimens surfaces showed that the highest mean surface roughness (136.6 nm) was found with the sulfuric acid treated group then coated with alumina, with AlN used as precursor (group II, subgroup C) and the significantly lowest mean surface roughness (6.4 nm) was found with the uncoated polished group (group I, subgroup A). The scotch tape test results revealed moderate bonding between the substrate and coatings. Group II, subgroup B showed the highest shear bond strength followed by ,(group II, subgroup C) with a cohesive failure then (group I, subgroup B) with prevalence of mixed failure and (group I, subgroup C) with prevalence of adhesive failure. The lowest shear bond strength values were for the uncoated (control) specimens; sulfuric acid treated zirconia and polished zirconia with an adhesive failure.Conclusions1. The deposition method of nano-alumina is a promising, yet complex method to be used on zirconia substrate according to both mechanisms.2. Meticulous selection of alumina precursors, pH, temperature and stirring time as crucial & sensitive parameters in co-precipitation of alumina on zirconia substrates.3. Aluminum nitride is a more suitable precursor for nano-alumina deposition from suspension on zirconia substrate.4. The use of sulfuric acid as an innovative surface pre-coating method to the zirconia indicates its direct beneficial influence on surface roughness and bond strength of zirconia substrates with adhesive cement resin.5. Control polished specimens had a negative influence on strength showing the lowest shear bond strength values to adhesive resin cement of all subgroups.