The recovery force of Ti-Nb coated and uncoated TiNi shape memory alloy rods was investigated. The rods were 6.0 mm, 6.5 mm and 7.0 mm in diameter respectively. The mean transition temperature was 33.0 degrees C. The rods were stored at -18 degrees C and pre-bent with a three-point bending fixture, the span was 20. 0 centimeters and the deflections were 5.0 mm, 10.0 mm, 15.0 mm and 20.0 mm, respectively. The rods were then heated in a constant temperature saline solution chamber. The experimental temperature was 37.0 C and 50.0 C respectively. The recovery force was measured in a constant displacement mode on biomaterial test machine. The results showed that the recovery force of the memory alloy rod increased with increasing recovery temperature, rod diameter and deformation of both Ti-Nb coated and uncoated surface. The recovery force of Ti-Nb coated rods of 6.0 and 6.5 millimeter in diameter was lower than the uncoated rods in the same diameter. However, the recovery force of 7.0-mm-diameter rods showed no significant difference between coated and uncoated surface.
Alloys ; chemistry ; Biomechanical Phenomena ; Coated Materials, Biocompatible ; Niobium ; Temperature ; Titanium

The gradient bioceramics coating was prepared on the surface of Ti-6Al-4V alloy by using wide-band laser cladding. And the effect of technological parameters of wide-band laser cladding on microstructure and sinterability of gradient bioceramics composite coating was studied. The experimental results indicated that in the circumstances of size of laser doze D and scanning velocity V being fixed, with the increasement of power P, the density of microstructure in bioceramics coating gradually degraded; with the increasement of power P, the pore rate of bioceramics gradually became high. While P = 2.3 KW, the bioceramics coating with dense structure and lower pore rate (5.11%) was obtained; while P = 2.9 KW, the bioceramics coating with disappointing density was formed and its pore rate was up to 21.32%. The microhardness of bioceramics coating demonstrated that while P = 2.3 KW, the largest value of microhardness of bioceramics coating was 1100 HV. Under the condition of our research work, the optimum technological parameters for preparing gradient bioceramics coating by wide-band laser cladding are: P = 2.3 KW, V = 145 mm/min, D = 16 mm x 2 mm.
Ceramics ; chemistry ; Coated Materials, Biocompatible ; chemistry ; Lasers ; Materials Testing ; Surface Properties ; Titanium ; chemistry ; X-Ray Diffraction

To study the method of anodic oxidation followed by hydrothermal treatment for cp titanium and to know bone response to thin hydroxyapatite layers in vivo, commercially pure titanium plates were anodized at 200 V-400 V with direct electric current density no more than 50 mA/cm2 for 15 minutes in the electrolytic trough. beta-glycerophosphate sodium(0.03-0.04 M) and calcium acetate(0.2-0.3 M) were used as electrolytes. Then, titanium plates were hydrothermal treated in the autoclave for 2 hours at 280 degrees C-300 degrees C. Polishing and grit-blasting surface was used as control to learn bone response to thin layers. Twelve rabbits were evenly divided into 3 groups, each group was implanted with 12 implants into the rabbits femoral bone. After 4, 8 and 16 weeks, implants were taken out and collected respectively and were made grinding slices. The bone-implant interface was observed with light microscope. And the bone-implant interface of polishing and layered implants after 8 weeks implantation was observed with scanning electron microscope. The element contents at the interface of polishing and layered implants before and after 8 weeks implantation were detected with EDAX. Results showed that there was hydroxyapatite(HA) precipitated on the titanium surfaceamellae bone in 8 weeks for thin HA coatings, and no HA debris were found at the interfacial zone. In addition, Ca and P content on the hydrothermal treated implant surface increased much more after implantation than that of polished implants. It was concluded that anodic oxidation followed by hydrothermal treatment could precipitate thin hydroxyapatie layer on the surface of cp titanium, which could improve early formation of woven bone and accelerate woven bone transferring to lamellae bone at the implanted site.
Animals ; Coated Materials, Biocompatible ; chemistry ; Electrodes ; Hydroxyapatites ; chemistry ; Materials Testing ; Oxidation-Reduction ; Rabbits ; Titanium ; chemistry

All samples were divided into three groups and subjected to three different surface treatments, i.e. untreated group, group etched with mixed acid of 1:1 HCl and H2SO4 followed by immersion in 6N NaOH solution at 60 degrees C for 24 h and group etched with mixed acid of 1:1 HCl and H2SO4 followed by immersion in 6N NaOH solution at 60 degrees C for 24 h then heated at 600 degrees C for 1 h. After soaked in simulated body fluid for two weeks, a thin calcium phosphate coatings was precipitated on the surfaces of the two treated samples. Results of SEM and EDX showed that calcium phosphate coatings on the surfaces of the titanium samples etched and heated were more even than the titanium samples etched without heating. The analysis of XRD demonstrated the main component of calcium phosphate coating was hydroxyapatite.
Body Fluids ; chemistry ; Calcium Phosphates ; chemistry ; Coated Materials, Biocompatible ; chemistry ; In Vitro Techniques ; Materials Testing ; Titanium

Ion beam enhanced deposition (IBED) has been applied to prepare titanium oxide layer on titanium alloy (Ti6A14V) in order to improve its biocompatibility. The layer on titanium alloy is even, and the elements Al and V in substrate are not detected. The layer is composed of TiO containing nitrogen oriented along (111) plane. The critical load of the layer in scratch test is 16.8 N. Morphological observation reveals the layer ends in a failure caused by plastic deformation.
Biocompatible Materials ; chemistry ; Coated Materials, Biocompatible ; chemistry ; Ions ; chemistry ; Surface Properties ; radiation effects ; Titanium ; chemistry ; X-Ray Diffraction

HAP-Glass-alpha-Al2O3 gradient coating on alumina ceramics substrate was prepared by multi-layer slurry-dipping and sintering process, effects of the composition of the coating on the microstructure and adhesion strength of the gradient coating were studied. R2O-Al2O3-B2O3-SiO2 system glass with low softening temperature and thermal expansion was used in the gradient coating. The composition of the coating was varied from interface to surface layer, i.e. the HAP concentration increased and glass concentration decreased gradually from the under layer to the surface layer. A suitable amount superfine alpha-Al2O3 was added in the gradient coating to reinforce the bonding strength between the coating and substrate. The results show that the use of R2O-Al2O3-B2O3-SiO2 system glass is propitious to sintering the coating at low temperature and to combination between the coating and substrate. The addition of superfine alpha-Al2O3 can reinforce the bonding strength between the coating and substrate, the highest bonding strength is about 48.2 MPa.
Adhesiveness ; Aluminum Oxide ; chemistry ; Ceramics ; chemistry ; Coated Materials, Biocompatible ; chemistry ; Durapatite ; chemistry ; Glass ; chemistry

This is a report on the research of HA/Ti6Al4V composite implants that were successfully fabricated by radio frequency magnetron sputtering (RF-MS) technique. The mechanism and bioactivity of these implants immersed in simulated body fluid (SBF) were investigated. Changes in surface morphology, interfacial bond state, crystal structure and phase composition of HA coating before and after immersing in SBF were characterized by Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Results indicate that a new substance on the surface of HA implant coatings produces accompanying with the dissolution of coatings. The substance is bone-like apatite containing CO3(2-) and lacking of Ca2+. Its ratio of n(Ca)/n(P) is about 1.56. This substance has very small grain size and similarly amorphous structure. Its structure and composition are similar to those of natural bone. Thus, it has good biocompatibility and bioactivity.
Biocompatible Materials ; Coated Materials, Biocompatible ; chemical synthesis ; Durapatite ; chemical synthesis ; Magnetics ; Materials Testing ; Prosthesis Implantation ; Radio Waves ; Titanium ; chemistry

OBJECTIVEThe aim of this study was to establish sol-gel technique of coating titanium on the surface of Ni-Cr alloy (PFM) in order to enhance corrosion resistance and reduce corrosive rate in oral cavity.

METHODSThe sol-gel technique included four steps: (1) pre-treatment; (2) preparation of sol; (3) coating; (4) heat treatment. Elements on the surface of Ni-Cr alloy were analyzed with X-ray photoelectron spectroscopy.

RESULTSAfter coating Ti, the surface of Ni-Cr alloy looked light golden without particles, blisters and fragments. Besides Ni and Cr, titanium was found on surface of Ni-Cr alloy after coating. With Ar(+) ion carving-corrosion figure, the thickness of titanium was about 20 - 80 microm.

CONCLUSIONWith sol-gel technique, titanium could be coated on the surface of Ni-Cr alloy.

Chromium Alloys ; chemistry ; Coated Materials, Biocompatible ; Dental Alloys ; chemistry ; Dental Materials ; Gels ; Humans ; Materials Testing ; methods ; Nickel ; chemistry ; Titanium ; chemistry

A simple plasma spraying method was employed in coating hydroxyapaptite (HA) on to carbon/carbon composites (C/C composites). The morphology of the coating was examined under scanning electron microscope (SEM). The phase constitutions of the HA coating were determined by X-ray diffractometer (XRD). The shear strength of the HA coating-C/C composite substrates was detected. A hydroxyapatite coating with rough surface was observed. A considerable amount of amorphous phase appeared as a result from the coating process, which could be transformed into the morphous phase crystalline HA after subsequent heat treatment. The shear strength between the HA coating and C/C composite substrates was 7.15 MPa.
Bone Substitutes ; chemistry ; Carbon ; chemistry ; Carbon Compounds, Inorganic ; chemistry ; Coated Materials, Biocompatible ; chemistry ; Durapatite ; pharmacology ; Humans

The surface treatment method for improving the functions of artificial joint metal materials and its properties have been sketched out in this paper. The purpose and the method of ceramic materials for coating and metal surface pre-treatment are explained and we have also discussed the bioactive ceramic coating and its function.
Ceramics ; Coated Materials, Biocompatible ; Joint Prosthesis ; Materials Testing ; Metals ; Prosthesis Design ; methods ; Surface Properties ; Titanium ; chemistry