c-3,t-3-Dimethyl-r-2,c-6-diphenyl­piperidin-4-one

In the title compound, C19H21NO, the piperidine ring adopts a chair conformation. The two phenyl rings attached to the piperidine ring at 2 and 6 positions occupy equatorial orientations and the dihedral angle between them is 57.53 (11)°. In the crystal, the mol­ecules are connected via weak inter­molecular C—H⋯π inter­actions, leading to a zigzag chains

c-3,t-3-Dimethyl-4-oxo-r-2,c-6-diphenyl­piperidine-1-carboxamide

In the title compound, C26H26N2O2, the piperidinone ring adopts a distorted boat conformation. The two phenyl rings substituted at positions 2 and 6 of the piperidinone ring occupy axial and equatorial orientations, which are approximately perpendicular to each other [89.14 (8)°]. The phenyl­carbamoyl group adopts an extended conformation. The crystal structure is stabilized by inter­molecular C—H⋯O inter­actions

Corrosion behavior of commercially pure Mg and ZM21 Mg alloy in Ringer’s solution – Long term evaluation by EIS

Evaluation of the corrosion behavior of commercially pure magnesium (CP-Mg) and ZM21 Mg alloy immersed in Ringer’s solution for 92 h by electrochemical impedance spectroscopy (EIS) is addressed. The formation of a compact layer of well-developed rod-like aragonitic CaCO3 crystals and its subsequent thickening with increase in immersion time offers a higher corrosion protective ability for ZM21 Mg alloy. The formation of a mud-crack pattern and a large number of clusters of needle-like crystals offers a relatively lower corrosion resistance for CP-Mg. The study suggests that ZM21 Mg alloy is a promising candidate material for the development of degradable implants

1-Acetyl-c-3,t-3-dimethyl-r-2,c-6-diphenyl­piperidin-4-one

In the title compound, C21H23NO2, the piperidine ring adopts a distorted boat conformation. The two phenyl rings form dihedral angles of 64.6 (1) and 87.8 (1)° with the best plane through the piperidine ring. The crystal packing is governed by inter­molecular C—H⋯O inter­actions

1-Chloro­acetyl-3,3-dimethyl-2,6-di­phenyl­piperidin-4-one

In the mol­ecule of the title compound, C21H22ClNO2, the piperidine ring adopts a distorted boat conformation. The two phenyl rings are nearly orthogonal to each other with a dihedral angle of 87.1 (1)°. In the crystal structure, the mol­ecules are linked into a three-dimensional network by C—H⋯O and C—H⋯π inter­actions

Effect of Thermal Oxidation on Corrosion Resistance of Commercially Pure Titanium in Acid Medium

This article addresses the characteristics of commercially pure titanium (CP-Ti) subjected to thermal oxidation in air at 650 A degrees C for 48 h and its corrosion behavior in 0.1 and 4 M HCl and HNO3 mediums. Thermal oxidation of CP-Ti leads to the formation of thick oxide scales (similar to 20 mu m) throughout its surface without any spallation. The oxide layer consists of rutile- and oxygen-diffused titanium as predominant phases with a hardness of 679 +/- A 43 HV1.96. Electrochemical studies reveal that the thermally oxidized CP-Ti offers a better corrosion resistance than its untreated counterpart in both HCl and HNO3 mediums. The uniform surface coverage and compactness of the oxide layer provide an effective barrier toward corrosion of CP-Ti. The study concludes that thermal oxidation is an effective approach to engineer the surface of CP-Ti so as to increase its corrosion resistance in HCl and HNO3 mediums

1-Dichloroacetyl-3,3-dimethyl-2,6-diphenylpiperidin-4-one

In the title compound, C21H21Cl2NO2, the piperidine ring adopts a distorted boat conformation. The two phenyl rings are approximately perpendicular to each other, with a dihedral angle of 86.12 (7)°. Molecules are linked into centrosymmetric dimers by pairs of bifurcated C—H...O hydrogen bonds, forming R22(10) and R22(14) ring motifs, and an intramolecular C—H...O link also occurs

Electrodeposition of hydroxyapatite coating on magnesium for biomedical applications

The effectiveness of hydroxyapatite (HA) coating prepared by electrodeposition technique in improving the corrosion resistance of commercially pure magnesium (CP-Mg) in simulated body fluid (SBF) is addressed. The coating formed in as-deposited condition is identified as dicalcium phosphate dehydrate (DCPD) (Brushite), which is converted to HA after immersion in 1 M NaOH at 80A degrees C for 2 h. The XRD patterns and FTIR spectra confirm the formation of DCPD and HA. During electrodeposition, the H2PO4 (-) ion is reduced and the reaction between Ca2+ ions and the reduced phosphate ions leads to the formation of DCPD, which is converted to HA following treatment in NaOH. The deposition of HA coating enables a threefold increase in the corrosion resistance of CP-Mg. The ability to offer a significant improvement in corrosion resistance coupled with the bioactive characteristics of the HA coating establish that electrodeposition of HA is a viable approach to engineer the surface of CP-Mg in the development of Mg-based degradable implant materials

Corrosion resistant Ti alloy for sulphuric acid medium: Suitability of Ti–Mo alloys

The corrosion resistance of Ti–Mo (5, 10, 15 and 25wt% molybdenum) alloys in 5–25% sulphuric acid was evaluated.The Ti–Mo alloys offered a better corrosion resistance than commercially pure titanium (CP-Ti). The higher impedance values, higher phase angle maximum, ability to reach the phase angle maximum at relatively lower frequencies, ability to exhibit a constant phase angle maximum over a wider range of frequencies, higher phase angle values at 0.01 Hz, have confirmed the formation of a stable passive oxide film on Ti–Mo alloys. The study recommends the use of Ti–Mo alloys, particularly Ti–25Mo alloy, as a suitable material of construction for sulphuric acid medium