PubMed · 14157446
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R J MORGAN, T O COSTON. 1964. DEMODEX BLEPHARITIS.. https://doi.org/10.1097/00007611-196406000-00016
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The photoelectrochemical response of nanoporous films, obtained by anodization of Ti and W substrates in a variety of corrosive media and at preselected voltages in the range from 10 to 60 V, was studied. The as-deposited films were subjected to thermal anneal and characterized by scanning electron microscopy and X-ray diffraction. Along with the anodization media developed by previous authors, the effect of poly(ethylene glycol) (PEG 400) or D-mannitol as a modifier to the NH4F electrolyte and glycerol addition to the oxalic acid electrolyte was studied for TiO2 and WO3, respectively. In general, intermediate anodization voltages and film growth times yielded excellent-quality photoelectrochemical response for both TiO2 and WO3 as assessed by linear-sweep photovoltammetry and photoaction spectra. The photooxidation of water and formate species was used as reaction probes to assess the photoresponse quality of the nanoporous oxide semiconductor films. In the presence of formate as an electron donor, the incident photon to electron conversion efficiency (IPCE) ranged from approximately 130% to approximately 200% for both TiO2 and WO3 depending on the film preparation protocol. The best photoactive films were obtained from poly(ethylene glycol) (PEG 400) containing NH4F for TiO2 and from aqueous NaF for WO3.
The purpose of the present study was to investigate the efficacy of four different fluoride etchants in titanium bonding. The etchants were aqueous solutions of 5 wt% sodium fluoride (NaF), ammonium fluoride (NH4F), sodium hydrogen fluoride (NaFHF), and ammonium hydrogen fluoride (NH4FHF). Cast specimens of commercially pure titanium were air-abraded with alumina, etched for 30 seconds, and then primed with a phosphate primer. An acrylic rod was bonded to the specimen with a tri-n-butylborane-initiated self-curing luting agent. Shear bond strengths were determined before and after 10,000 thermocycles. Regarding pre-thermocycling bond strength, there were no significant differences among the etchants. After thermocycling, there was a decrease in bond strength for all groups. Nonetheless, the bond strengths of NaFHF and NH4FHF were significantly higher than those of NaF, NH4F, and non-etched control. In terms of bonding durability between resin and titanium, it was significantly improved when the titanium surface was microscopically roughened with alumina blasting and etching using NaFHF or NH4FHF.
The purpose of this study was to investigate the efficacy of an etchant in titanium bonding. The aqueous etchant consisted of 0, 5, or 10 wt% ammonium hydrogen fluoride (AHF) in combination with 0, 0.03, 0.3, or 3 wt% cupric chloride (CC). The two primers used were a phosphate-methacrylate primer and a thiophosphate-methacrylate primer, and two self-curing resins (Super-Bond C&B and MT) were employed as luting agents. Disk specimens were cast with a commercially pure titanium. The surface was air-abraded with 50 microm alumina, etched for 10 s, rinsed with water, and then air-dried. The primer was applied to the bonding area (5 mm in diameter), and an acrylic rod was bonded to the specimen with the luting agent. Shear bond strengths were evaluated after 24 h of water storage and following 10,000 thermocycles (4 degrees C and 60 degrees C). The post-thermocycling bond strength was significantly increased with each of the two primers compared with the unprimed controls. The etchant containing 5 wt% AHF and 0.3 wt% CC further increased their durability, and microscopic observation revealed that innumerable submicron crystals were created on the etched specimen. The present results suggest that the chemical etching improved the resin bonding durability to titanium in combination with the primer used.