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Titanium is a highly operational alloy for use in dental implants. Surface inertness of the titanium alloy surfaces reduces osseointegrate, raising concerns about implant loosening. Hydroxyapatite (HA)-rich porous titanium surfaces with moderated surface roughness have better osteoconductivity. This study focused on the surface alteration of Ti6Al4V via hydroxyapatite mixed electric discharge-assisted centerless turning (HA-mixed-EDCLT) to find the optimum surface. The experiments were planned based on a four-factor, three-level Box-Behnken design. HA-powder concentration (Cp), revolutions per minute (RPM), duty factor and impulse current (IP) were the input parameters. The Ra value of machined surfaces ranged from 1.12μm to 1.63μm, which is in the bone growth supportive implants range. The average hardness reached 415.8–962.7HV, where untreated surfaces’ hardness was 340±6HV. Porous, hydrophilic coating with a high Ca, P, and O content deposited on the implant surfaces supports the biocompatibility of implants. Analysis of the elements and compounds shows that the machined surface layer is rich with Ca3(PO4)2 and TiO2,which improves the bioactivity of the alloy. [ABSTRACT FROM AUTHOR]

Diamond grinding-assisted electro-discharge (DGAED) machining is a hybrid machining process which can be used to improve the material removal rate (MRR) for the difficulty to machine materials like superalloys, ceramics, and composites. The main aim of this paper is to develop a model for DGAED machining of titanium nitride-aluminum oxide (TiN-Al2O3) ceramic composite for predicting MRR. TiN-Al2O3 ceramic composite finds industrial application due to its properties like high resistance to abrasion wear, chemical stability, hardness, and low friction coefficient. The characteristic features of DGAED machining of the TiN-Al2O3 ceramic composite are explored through response surface methodology (RSM) for face-centered central composite rotatable design (CCRD) with seven-center-point scheme. Wheel speed (S), peak current (I), pulse on time (ton), and duty factor (DF) are taken as control factors while MRR is taken as the performance parameter. The experimental results for MRR are analyzed and regression equation for material removal rate is obtained. The surface topography shows that melting and thermal spalling are primary material removal mechanisms. Microcracks and micropores are found diminished on the machined surface and MRR is improved as the wheel rotation speed increased. [ABSTRACT FROM AUTHOR]

Abrasion resistance is a property of a marble which gives an indication of the marble wearing quality when it is exposed to foot traffic. This property is tested according to ASTM C241 standards. Abrasion further helps in determining whether a marble is economically desirable and practical for floors, stairs, etc. For this, 48 samples were selected from different processing units of Rajasthan and were tested. Regression analysis was carried out to investigate the relation between the abrasion resistance and the mechanical properties of marbles determined according to ASTM standards. Although, it is believed that abrasion resistance of many materials are greatly affected by its hardness and it increases with the increase in the hardness. The correlations of abrasion resistance was found to be highly related with mechanical properties like modulus of rupture (R² = 0.96), compressive strength (R² = 0.94), flexural strength (R² = 0.96) along with hardness (R² = 0.84) while the water absorption (R² = 0.08) and density (R² = 0.44) were found to be less correlated. [ABSTRACT FROM AUTHOR]