| Purpose: In this experiment, titanium surfaces were etched by variousconcentrations hydrochloric acid and then heating. Titanium porcelainspecimens were prepared. The titanium-ceramic bonding strength wasevaluated by three point bending test. The aim of this experiment was todiscuss the effects of titanium surfaces treated by etching heating ontitanium-ceramic bonding strength and to provide the experimental evidencefor the technical evolution of pure titanium ceramic and the improvement oftitanium-ceramic bonding strength.Method:1Specimens Preparation: Thirty-six prepared titanium with the specificationof (25±1)mm×(3±0.1)mm×(0.5±0.05)mm were randomly divided into fourgroups after the surfaces girded and the thickness controlled among0.5±0.05mm.Each group contains9Specimens. Group A was controlled groupwith no treatment. Group B, C and D were separately etched by5%,15%,25%hydrochloric acid for40minutes in boiling environmental and coolednaturally in room temperature, and ulcer-sonically cleaned in distilled waterand dried fully. And then specimens were heated in600℃lasted for6minutesin air pressure, heated at760℃at the speed of100℃/min with the pressureof50hPa lasted for1minute, and then cooled naturally at room temperature.One titanium specimen was got out of each group, the lateral side polished,and left for electronic-microscope observing for the oxide membrane of thetitanium surfaces. For the rest of32titanium specimens, at the central8mmarea of the surfaces of25mm×3mm titanium side, combination agentTi-Bond was coated uniformly. The surfaces were fully covered, and thethickness were the same, and burned according to the programs provided bythe manufacturer Duceratin Kiss.Ceramic powder (DK ceramic powder for short at below) was coated in conventional way according to the methodsprovided by the direction. Sheltered ceramic was coated by two steps-methodand keep the thickness among0.1±0.01mm, and burned according to theprograms provided by the manufacturer. Dentin ceramic was coated and thethickness were kept among1±0.1mm, and burned according to theprogram. The cuboids profile of general ceramic was polished with siliconcarbide paper of240#,400#,600#,800#,1000#in gradual steps in the samedirection with smaller force, and keep the specification within (8±0.l)mm×(3±0.l)mm×(1.1±0.l)mm. The ridges were clear and the shapes were uniform.Glaze by itself once. All the practices were done by the author himself. Onespecimen was got out in each group in random, and in served for scanningelectron microscopy with energy-dispersive spectrometry after the lateral sidewas polished.2Three points bending test: Universal mechanical testing machine was settled,two fulcrum points were apart from20mm, the radius of curvature of fulcrumpoints and pressure heads were1.0mm. Specimens placed with ceramic bodyside down and titanium metal surface side up. Vertical force were appliedslowly in the center of corresponding titanium part of8mm×3mm ceramicbody load at the speed of1.5mm/min until the titanium matrix and ceramicinterface crazed no matter which end, and the force values were recorded atthe fracturing moments. This test was done in room temperature. Thencalculated the bonding pressure of titanium-ceramic by the equation rb=k· Ffail3Field emission electron microscope scanning: The prepared titaniumspecimen were settled on the sample stage with the testing surfaces upsidefirmly, and sprayed with gold. The structures and forms of the titaniumoxidation layers were observed through field emission electron microscopescanning.4Elements line scan analysis: Prepared titanium specimens were placed on thesample stage with the testing surfaces upside firmly. The types and themigration distances of the elements in the titanium ceramic interface areas were analyzed by line scanning with Inca Energy350Elements line scansmicroscopy.5The statistical treatment: Three point bending experimental results statisticswere analyzed with SPSS13.0statistical analysis software. OneWay-ANOVA and SNK test were chosen if the dates were normally and thevariances were same. Ranking test was chosen if the dates were not normallydismissed or the variances were not neat. Inspecting standard α=0.05.Result:1Macroscopic observation of titanium specimens after etched: The quality oftitanium specimens surfaces changed to rough. Along with the increase of theconcentration of hydrochloric acid, the color of the specimens changed intoash from the shallow to deep (Fig.1),the color of hydrochloric acid liquidshowed deeper purple after etched.2Three point bending mechanical test results: Group A was25.92±3.49MPa,group B was30.25±3.48MPa, group C was41.37±4.48MPa, group D was34.71±4.06MPa(Table1). The experimental dates were normally dismissedand the variances were the same according to SPSS13.0statistical analysis, soOne Way-ANOVA was chosen. ANOVA results indicated that the overallmeans of groups were statistically significant different(P <0.05)(Table2).SNK separate comparing results showed that there exited statisticallysignificant differences between the overall means of every two groups (P <0.05)(Table3).3Field emission electronic microscope observing results: Group A (Fig.2)The surfaces of titanium specimens were clear and smooth, and there were nomicronsized oxidation layers. Group B (Fig.3) There were about the thicknessof1μm of oxidation layer appeared at the surfaces of titanium specimens, andthere was no boundary between titanium matrixes and oxidation layer. GroupC(Fig.4) There were about the thickness of2～3μm of oxidation layerappeared at the surfaces of titanium specimens, and there were no boundarybetween titanium matrixes and oxidation layer, but there were smaller holes.Group D(Fig.5) There were about the thickness of4.5μm of oxidation layer appeared at the surfaces of titanium specimens, and there were boundarybetween titanium matrixes and oxidation layer, there were smaller not goodshapes holes and the fracture of oxidation layer was loose.4Elements line scanning and analyzing results: The general trend of elementsmigration in the four groups: The content of Ti changed to smaller fromtitanium matrixes to boundary areas. The content of Si, O changed to smallerfrom ceramic body to boundary areas. The content of O was smallerrespectively to Si. Elements Al, Na, K, Zr contained lower in ceramic, andthere existed appearance of migration into boundary areas.Group A (Fig.6) The thickness of reaction layer was about1μm, and theangles of elements curves were obtuse and the declines were steep. Ti hadmigrated to the whole reaction layer. Si had migrated about0.7μm into thereaction layer. O had migrated about0.5μm into the reaction layer. Group B(Fig.7) The thickness of reaction layer was about1.5μm, and the angles ofelements curves were relatively pliable. Ti had migrated about1.2μm into thereaction layer. Si had migrated about1μm into the reaction layer. O hadmigrated about0.5μm into the reaction layer. Group C (Fig.8) The thicknessof reaction layer was about2.5μm, and the angles of elements curves werepliable. Ti had migrated about2.5μm into the reaction layer. Si had migratedabout2μm into the reaction layer. O had migrated about1μm into the reactionlayer. Group D (Fig.9) The thickness of reaction layer was about4.5μm,and the angles of elements curves were pliable and flat. Ti had migratedabout3μm into the reaction layer. Si had migrated about4.5μm into thereaction layer. O had migrated about2μm into the reaction layer.Conclusion:1Titanium surfaces treated by etching and heating can improve thetitanium-ceramic bonding strength.2The maximum titanium-ceramic bonding force was the15%hydrochloricacid treatment,that of5%hydrochloric acid treatment and25%hydrochloricacid treatment was smaller, that of no treatment was minimum. |
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